Dietary Sources

Beta glucans are naturally occurring polysaccharides that serve as energy stores and structural components of plant walls found in a variety of foods including oats, barley, seaweed, as well as many types of microorganisms (bacteria, yeast and fungi).  While they all share a “common” beta chemical bond between the individual glucose units, there are many subtle, but important, differences in structure within the beta glucan family that lead to large differences in function and potential health benefits.  When choosing a beta glucan, it is key to focus on what clinical research is available to support the specific ingredient’s mechanism of action, demonstrate effectiveness for the desired benefit, and show the safety of the ingredient.

Mushroom Beta-Glucans

As the chemical composition of each type of mushroom varies, so does the biological activities of their beta glucans.  Although are associated with immune health benefits, their molecular structure is varied and inconsistent, making it difficult to characterize their efficacy ².  The most studied strain of mushroom beta glucan is lentinan, a substance derived from Lentinus edodes (Shiitake) with a beta-1,3-D-glucan backbone comprising very short beta-1,6 side chains.

Further clinical research is needed to fully understand how each type of mushroom beta glucan works ².

Yeast Beta-Glucans

Yeast beta-glucan are  one of the most extensively studies of the beta-glucans.  A recent review recommends that future research should define the origin, molecular weight, and structure of yeast beta-glucans by using standardised tools (e.g. structural analysis, chemical degradation, nuclear magnetic resonance) to accurately characterise and clarify structure–function relationships ³.  For this reason, choosing a generic yeast beta-glucan may not deliver the targeted health benefit which should be demonstrated using a well characterised ingredient in clinical trials.

Yeast-derived beta glucans usually originate from either baker’s yeast or brewer’s yeast.  Even though both are structured as beta 1,3/1,6 glucan from Saccharomyces cerevisiae, differences in the source (or strain) of yeast and the method used to isolate and purify the yeast beta-glucan are important factors affecting the final structure of the yeast beta-glucan ⁴ and may ultimately influence biological activity ⁴.

Yeast Beta-Glucans Impact on Immune Health

The immune system has the ability to recognise and eliminate pathogens by first activating the innate (general) immune response, which acts in a fast and un-targeted manner to phagocytose and eliminate the invader.  Innate immune cells can also adapt to challenge and alter subsequent responses, which is referred to as trained immunity.

The current paradigm for the immunomodulating action of yeast beta-glucans is through improving the innate immune system by making key white blood cells better able to find and kill potential pathogens ^{1, 5}.  Studies into the cellular and molecular mechanisms of action show that beta-1,3/1,6-glucans are engulfed and processed by macrophages and dendritic cells that later travel to the different immune organs releasing fragmented soluble beta-1,3-glucan particles.  This results in the priming of leukocytes via certain receptors including Dectin-1 and leads to enhanced immuno-surveillance and improved antimicrobial and inflammatory responses ¹.  In theory this should translate into enhanced resistance to infection.

Upper respiratory tract infections (URTIs) are the leading cause of acute disease in humans and poses a substantial burden to the healthcare system ⁶.   A specific baker’s yeast beta-glucan containing a highly purified natural beta-1,3/1,6-glucan has been shown to reduce either the incidence and/or duration or severity of URTIs in clinical trials with children ⁷, athletes ⁸ and those engaging in intense exercise ^9,10.

A meta-analysis of 13 randomised controlled trials has also demonstrated that yeast beta-glucans could significantly reduce the incidence and duration of URTIs.  However, due to the high heterogeneity and small number of included studies, more high-quality research and clinical trials are warranted ¹¹.

Yeast beta-glucans area also being explored for their potential to improve vaccine effectiveness ¹².

This article was published in April 2020 and updated on April 14, 2026.

Walking into a supermarket today or shopping online, it is hard to miss the shift in the types of products for sale such as matcha coffees, lion’s mane teas, ginseng soft drinks and ashwagandha gummies.  All these products stem from the meteoric rise of functionalism in our foods and beverages.  And whilst these products are often supercharged by social media trends, it is more embedded in a population that is seeking to be healthier through what they eat and drink.

Botanicals are part of that uptake.  Previously associated as alternative ancient medicine but now continuously sought out by a population seeking to improve their immune health, sleep, cognitive function, and overall wellbeing ¹.  There is no internationally shared definition for the term ‘botanical’; however, according to the European Food Safety Authority (EFSA) a botanical can be seen as herbs, roots, flowers, mushrooms and other plant-derived extracts ².  Other jurisdictions classify these ingredients differently – such as dietary supplements in the US, functional foods or Kampo medicines in Japan, or traditional herbal products in India and China – reflecting the lack of global consensus on how botanicals are categorised ³.

Despite this regulatory heterogeneity, the economic significance of botanicals is substantial.  The US saw its botanical supplement industry reach USD 13.57 billion in 2024 ⁴, while the European herbal market was valued at approximately USD 7.5 billion in 2023 ⁵.  Latin America’s herbal supplement market stood at USD 3.39 billion in 2024 ⁶, and Asia-Pacific represents the fastest-growing region globally, driven by deep-rooted traditions in herbal medicine across China, India, and Japan ⁷.  As the approach to ageing shifts from living longer to living healthier for longer, botanicals will likely continue to soar in popularity.  This growing demand for botanical dietary supplements stems from positive attitudes toward ‘natural’ products and an expanding body of evidence supporting their beneficial effects on human health.

Plants are rich sources of diverse bioactive compounds, including coumarins, flavonoids, phenolics, alkaloids, terpenoids, tannins, essential oils, lectins, polypeptides, and polyacetylenes; and consequently, their potential health benefits are unsurprising ⁸.  Ashwagandha (Withania somnifera) has been shown to reduce perceived stress and anxiety in adults ⁹, giving clinical weight to its reputation as an adaptogen.  Turmeric (Curcuma longa), a curcuminoid-rich plant, has meaningful reductions in pain and improvements in physical function reported among people with knee osteoarthritis ¹⁰.  Elderberry (Sambucus nigra), rich in flavanols, has been found to reduce duration and severity of common cold and flu symptoms ¹¹.

Despite these positives, caution is warranted when botanicals are used for medicinal purposes.  Their “natural” origin often leads consumers to perceive them as inherently benign, fostering assumptions of safety that are not always justified.  This perception has contributed to widespread misunderstanding surrounding botanical products and their appropriate use.

A Credibility Issue

Consider Emily.  Like many Americans, she has begun to struggle with knee pain linked to chronic inflammation.  On the advice of friends and a growing body of academic research, she adds turmeric to her routine as part of a broader, holistic approach.  The label states a meaningful dose of curcuminoids, the “active ingredient” most often linked to turmeric’s health benefits.  Weeks later, little has changed, and independent testing reveals that the product contains far less curcuminoids than advertised.  Emily does not blame processing choices or the environmental conditions in which the turmeric was grown.  She blames the plant itself, stops trusting botanical supplements altogether and possibly takes to social media where it can amplify distrust far beyond a single purchase.

Emily’s story, while hypothetical, reflects a real and measurable problem.  Large-scale global assessments of nearly 6,000 commercial herbal products across 37 countries have found roughly 27% were adulterated in some way, illustrating how unmanaged variability and poor verification can erode confidence across the category ¹².   The answers to seemingly simple questions, what exactly is in the product, how consistent it is batch to batch and whether it reflects what the label claims are not always clear and the solutions are more complex.

Plants are characteristically intricate organisms, and their biological makeup is inherently linked to the abiotic and biotic factors it experiences during growth ¹³.  For example, anyone who has tasted oranges grown in different parts of the world will recognise the effect of geography.  Fruits from warmer, sunnier regions often taste sweeter, while those grown in cooler environments can be sharper or more acidic – despite all being, unequivocally oranges.  Soil composition, rainfall, temperature, and harvest timing subtly but consistently shapes flavour.

The same principle applies to botanical supplements; species such as ashwagandha or ginseng, which are cultivated across multiple geographic regions, can differ meaningfully in their chemical profiles depending on where and how they are grown.  Lan et al.¹⁴ showed that Panax ginseng cultivated under different forest canopies, coniferous, broad-leaved, and mixed forests  exhibited statistically significant differences in both total ginsenoside content and individual ginsenosides.  These subtle changes matter when products are expected to deliver certain health outcomes.

The challenge is compounded by the way botanical products are processed.  Raw materials are often sourced from multiple growers and processed in different ways, even within the same supply chain.  For example, Kumar et al.¹⁵ in Withania somnifera (Ashwagandha) the principal bioactive compounds such as withaferin A, withanones, and withanosides are unevenly distributed across plant parts, with leaves enriched in certain withanolides and roots in withanosides. This means products made from roots, leaves, or whole plants can contain markedly different profiles of these compounds.  As a result, two products derived from the same plant but processed differently can vary meaningfully in both composition, potential benefit and therefore quality.

Figure 1 – From plant to product: where botanical variability enters the supply chain. At each stage from genetics, through growing conditions and sourcing to processing – new sources of variability are introduced and compound through to the finished product.

When identity and composition are not carefully verified, variability can slide into misidentification or even deliberate substitution.  Cheaper materials may be used to imitate more valuable ingredients, such as peanut skins being substituted for the A-type proanthocyanidins associated with cranberries ¹⁶.  These practices do more than mislead consumers: they risk undermining efficacy claims and, in some cases, introduce safety concerns that neither the label nor the user expects.  Managing these risks calls for a different way of thinking about quality.  Modern analytical science offers the tools to make that complexity manageable.

Overview of Analytical Techniques

For much of history, botanical quality was judged by eye and by a small number of simple tests.  A root or leaf was inspected to see if it “looked right,” and one or two marker compounds were measured to suggest identity or strength.  These methods are still useful and, in many settings, perfectly adequate.

However, modern botanical supply chains are far more complex.  Ingredients are grown in different regions, across seasons, and under subtly different environmental and processing conditions.  In this context, analytical techniques play a critical role in reducing uncertainty about raw materials, verifying authenticity of source ingredients, and supporting regulatory compliance across different markets.  These techniques increasingly fall into two broad categories: 1. targeted methods, which measure predefined metabolites, and 2. untargeted methods, which characterise the overall bio-chemical system.

Targeted Analytical Techniques

Targeted approaches are designed to answer focused questions: Is compound X present?  Is it within specification?  They rely on prior knowledge of marker compounds, specific chemical constituents used to verify the identity, purity, or potency of a botanical material, as well as reference standards. As such, they are central to regulatory compliance and routine quality control.

Gas Chromatography–Mass Spectrometry (GC–MS)

GC–MS examines the volatile fraction of a botanical.  The sample is vapourised and carried by an inert gas through a narrow column, where compounds separate based on their interaction with the stationary phase.  As each compound exits the column, it is ionised and fragmented, producing a characteristic mass spectrum ¹⁷.

This combination of separation and structural identification makes GC-MS ideal for aroma profiling, characterisation of , residual solvents, and small volatile adulterants.  Its limitation is fundamental: larger bioactive phytochemicals (BAPs), including glycosides, polyphenols, curcuminoids, ginsenosides, and withanolides are non-volatile and thermally unstable.  This means they fall outside the analytical scope of GC-MS unless chemically derivatised ¹⁷.

High-Performance Liquid Chromatography (HPLC)

HPLC uses high pressure or ultra-high pressure (UPLC) to push a liquid sample through a packed column, separating compounds based on their polarity due to the interaction between the stationary and mobile phases.  Detection is most often optical (e.g., UV/Visible), and methods are engineered around compounds with known chromatographic behaviour ¹⁸.  Its strengths are precision, reproducibility, and scalability across laboratories (Figure 2).  By design, however, it only detects chemistry the method defines; compounds outside that analytical window remain undetected.

Figure 2 – Illustrative HPLC-UV chromatogram of an ashwagandha (Withania somnifera) root extract at 227 nm, showing separation of six withanolides marker compounds. Retention times and peak heights are simulated for illustrative purposes and do not represent real analytical data.

Liquid Chromatography Mass Spectrometry (LC–MS)

When liquid chromatography is coupled to mass spectrometry, chromatographic peaks gain molecular specificity.  Features are defined not only by retention time but by their mass-to-charge ratio and fragmentation pattern.  When a photodiode array (PDA) detector is also coupled, UV/visible absorbance data can provide additional confirmation.  In practice, this configuration is most applied as a targeted technique used to confirm and, depending on the type of mass analyser, quantify predefined analytes ¹⁸.

Untargeted Analytical Techniques

Untargeted techniques shift the analytical question.  Rather than confirming the presence of specific compounds, they aim to capture the overall chemical composition of a botanical.

High-Resolution (LC–MS)

When liquid chromatography is paired with high-resolution mass analysers — such as Time-of-Flight (ToF), Orbitrap, or hybrid Q-ToF instruments — the analytical window opens significantly.  These platforms measure mass with enough accuracy to infer molecular formulas directly from the data ¹⁹.

Depending on how they are configured, high-resolution LC/MS systems can operate in both targeted and untargeted modes: confirming known compounds or scanning broadly for hundreds to thousands of features without preselecting what to look for ²⁰.  This flexibility makes them especially valuable in botanical quality assessment, where the question is not just “is compound X present?” but “does this material look like the real thing?”.  The resulting datasets are complex, but they become meaningful when compared against well-characterised reference profiles of genuine plant material.

NMR (Nuclear Magnetic Resonance) Spectroscopy

NMR places a prepared extract – whose composition reflects the extraction protocol used – in a strong magnetic field and probes how atomic nuclei respond to radiofrequency energy.  Each chemical functional group produces a distinct resonance, and the resulting spectrum integrates signals from all major molecular populations at once ²¹.  Because signal intensity is directly proportional to concentration, NMR is inherently quantitative and highly reproducible for major metabolites above its detection threshold, though sensitivity limits its ability to quantify trace-level components.  The result is a holistic chemical portrait that shifts with any meaningful change in composition, making it powerful for assessing overall integrity.

Modern analytical techniques make it possible to measure botanical chemistry in detail.  Yet, when used in isolation, each still answers only a narrow question.  In practice, no single method can fully describe a living system shaped by species, soil, climate, and processing.  What has emerged in response is metabolomics: an approach that treats botanical ingredients not as collections of isolated compounds, but as integrated bio-chemical systems.

Metabolomics: Beyond Markers to Fingerprints

Metabolomics describes the comprehensive measurement of all small molecules present in a biological system at a given moment.  In plants, this means capturing the full spectrum of sugars, organic acids, amino acids, phenolics, terpenoids, and countless other metabolites that collectively define a species and reflect how it has grown, been harvested, and processed ¹⁸.

Unlike traditional quality control, which reduces a complex extract to the concentration of one or two “marker” compounds, metabolomics treats each botanical as a multidimensional chemical fingerprint.  Using an untargeted approach, thousands of features are measured simultaneously.

This shift also changes the underlying question being asked.  Rather than asking whether a predefined compound falls within an acceptable range, metabolomic approaches ask whether the overall chemical behaviour of a material is consistent with that of an authentic plant.  In a conventional single‑marker framework, an extract is evaluated against one target analyte — for example, whether compound X meets specification.  As illustrated in Figure 3a, an authentic botanical extract and a deliberately spiked product can both pass this test, even though their underlying chemistry is fundamentally different.

Figure 3 – From single markers to system-level identity. Left: A traditional single-marker test asks whether a target compound (e.g., compound X) falls within the expected concentration range. Both an authentic extract and a spiked product (Product X) pass, illustrating how this approach can fail to distinguish genuine material from engineered imitations. Right: A Principal Component Analysis (PCA) score plot based on untargeted metabolomic profiling reveals the full chemical picture. Authenticated botanical samples (triangles) cluster within a coherent fingerprint space defined by natural variation, while spiked products (circles) fall outside this region — even when they meet a single-marker specification. Identity is defined by pattern, not a single value. 

Untargeted metabolomic profiling resolves this limitation by capturing the full chemical composition of the extract and interpreting it using multivariate statistical methods such as Principal Component Analysis (PCA).  As shown in Figure 3b, genuinely authenticated botanical samples cluster within a coherent chemical space shaped by natural biological variation, while materials that have been diluted, substituted, or engineered to satisfy a narrow marker specification fall outside this region, even when they comply with single‑compound criteria.  In this framework, identity is no longer defined by the presence or concentration of an isolated compound, but by whether the pattern of chemistry aligns with that of real plant material.

Overcoming Variability, Processing, and Adulteration

By shifting quality from single measurements to whole-pattern behaviour, metabolomics directly addresses the core problems that undermine botanical credibility: environmental and seasonal variability, processing effects, and adulteration.  Earlier we saw how geography alters plant chemistry, how different plant parts and extraction methods reshape composition, and how products can be engineered to satisfy a narrow specification.  Fingerprinting reframes these challenges.  Instead of forcing complex biology into a fixed number, metabolomic models learn how authentic plants vary and define the natural “cloud” they occupy.  This allows regional/environmental conditions to be differentiated as well as adulteration.

This principle is already playing out in practice.  In Panax ginseng, LC–MS metabolomics showed that roots grown under different forest canopies formed distinct but overlapping clusters, capturing the chemical impact of environment while still separating genuine ginseng from non-ginseng material ²⁰.  In Saw Palmetto, ¹H NMR fingerprinting grouped commercial products by extraction method and exposed samples that were diluted with cheaper vegetable oils, an artefact invisible to fatty-acid testing alone ²².  In black cohosh, metabolomic profiles reliably distinguished Actaea racemosa from closely related Asian species in finished supplements, even where DNA barcoding failed due to processing ²¹.

Turmeric shows the same vulnerability: products can meet curcuminoid specifications while diverging from authentic Curcuma chemistry through the addition of dyes or foreign starches; untargeted LC–MS places these materials outside the natural chemical space defined by real rhizome extracts ²³.  Each case reflects a problem described earlier: geography, processing, substitution, and engineered compliance – each demonstrates how fingerprinting restores meaning to identity.

Regulation, Traceability, and Ethical Sourcing

Metabolomics sits awkwardly within most current regulatory frameworks, which remain grounded in fixed identities and single-parameter specifications.  In the US, the FDA’s approach under DSHEA relies on declared species, GMP compliance, and targeted identity tests ²⁴.  In the UK, botanical products are assessed through MHRA and food standards pathways that similarly depend on pharmacopeial methods and marker compounds ²⁵.  EFSA’s evaluations across the EU are anchored to known constituents and safety thresholds.  On the other hand regulators in South America, such as ANVISA in Brazil or CONAL in Argentina, operate through monographs, species declarations, and defined assays ^23,26,27.

In the Asia-Pacific region, regulatory approaches are equally varied. Japan separates traditional medicines, regulated as drugs, from functional foods assessed under its FOSHU system ²⁸. China’s State Administration for Market Regulation overseas both traditional Chinese medicine and health food registration ²⁹, while India’s FSSAI governs botanical supplements as part of its broader food safety framework ³⁰. Australia’s Therapeutic Goods Administration takes a comparatively stringent approach, requiring listed or registered product status for complementary medicines ³¹.  Figure 4 shows the global regulatory landscape for botanical supplements.  These systems are effective for ingredients that behave like chemicals.  They are less equipped to accommodate evidence that expresses authenticity as a multivariate pattern rather than a single value.

Figure 4 – Global regulatory landscape for botanical supplements. Compiled from national regulatory authority publications and comparative reviews ^3,27,31–35.

Yet that very difference is what gives metabolomics its broader significance.  When reference libraries are built from well-documented plant material, chemical fingerprints can link finished products back to biological and geographic origin, creating continuity across the supply chain. This capability aligns closely with the aims of the Nagoya Protocol, which seeks fair and equitable benefit-sharing from the use of genetic resources ³⁶.  By anchoring products to authentic plant populations and documented provenance, metabolomic frameworks can reinforce claims of origin, deter substitution, and support sourcing models in which value flows back to the communities and ecosystems from where these botanicals originate from ³⁷.

Future Perspectives: From Verification to Design

Looking forward, metabolomics is poised to reshape how botanicals are verified, but also how they are developed and applied.  As datasets expand and chemical fingerprints are increasingly linked to biological outcomes, it becomes possible to move beyond generic claims toward evidence-based designs, identifying which metabolic patterns correlate with cognitive resilience, immune modulation, or stress adaptation.

Emerging work already shows that subtle shifts across networks of metabolites, rather than single “actives,” underpin many of these effects, particularly in complex systems such as the gut–brain and immune axes ³⁸.  In this context, metabolomics becomes a bridge between traditional botanicals and modern biotechnology: enabling targeted cultivation, optimised processing, and, ultimately, more personalised nutrition strategies that align plant chemistry with individual physiology.

Zinc is a popular nutrient in winter supplements.  It is an essential nutrient and the second most abundant trace element in the body, after iron ¹.  It is found in every cell in the body and involved in many bodily processes.  It is required by cells from both the innate (general) and adaptive (specialised) immune system ².

The innate immune system is the body’s first line of defence.  When pathogens like infectious bacteria or viruses get into the respiratory tract or gastrointestinal system, the innate immune system responds by sending cells like neutrophils or macrophages to remove the threat.  These cells try to engulf the invading pathogen or create enzymes to destroy it.

The adaptive immune system specifically targets the pathogen and takes over from the innate immune system.  It is often described as the ‘memory’ of our immune system.  Once exposed to a pathogen, the immune system can remember the identity of that pathogen for the future and quickly mount a defence specific to that pathogen.

The role of Zinc in the immune system includes:

• • helping to maintain the integrity of the skin and muscular membranes, preventing pathogen entry into the body.
  • supporting the growth and differentiation of immune cells.
  • supporting the phagocytic activity of monocytes, and help regulate cytokine release.
  • antibody production, particularly IgG and helping the immune system distinguish between “self” and “non-self” ³.

This role has been recognised in an approved European Union health claim for zinc, stating that it “contributes to the normal function of the immune system” and is available to foods that meet defined criteria within the EU ⁴.

Are there Recommended Intakes for Zinc?

Zinc recommendations range from 5 to 11mg per day for adults, varying by each global region ⁵.  In the US, the Institute of Medicine (IOM) recommendations are 11mg per day for men and 8mg per day for women ⁶.  Similarly, the Chinese Nutrition Society Reference intake (RNI) is 12mg per day for adult men and 8.5 mg per day for women⁸.  In Europe, the European Food Safety Authority has established a Population Reference Intake of 9.4 to 16.3mg per day for men with low to higher intakes of dietary phytate and 7.5 to 12.7mg per day for adults women with low to higher intakes of phytate ⁷.

Most people in developed countries get enough zinc through their diet, meaning their immune system isn’t missing the zinc it needs.  For example, in the US around 18% of people do not meet the Estimated Average Requirement (EAR) of zinc per day.  This means most people are not zinc deficient, but  certain people may still benefit from eating more zinc in their diet.

Where can Zinc be Sourced inDietary Sources

Zinc is mostly found in seafood, beef, poultry, beans, nuts, or fortified cereal.  Phytic acid, found in cereals, legumes, and nuts, is known to decrease zinc bioavailability ¹.  Evidence shows that the biofortification of varieties of staple crops may be useful in improving the zinc status of an individual⁵.

Table 1. Zinc content of common foods in the diet ⁹

What Happens with a Zinc Deficiency?

Zinc deficiency is a widespread global health issue, particularly prevalent in low- and middle-income countries.  About 17.3% of the world’s population ¹⁰ is at risk of inadequate zinc intake.  When the body doesn’t have enough zinc, it does not develop a strong immune response.  Zinc deficiency affects many different organs and tissues in the body with signs and symptoms varying by age ⁹.  For example, zinc deficiency can delay growth and cause diarrhoea and alopecia in children, and it can alter cognitive and psychological function in older adults.

Most people in developed countries get enough zinc through their diet but it can affect more vulnerable groups.  For example, the percentage of people in the US that do not meet the  Estimated Average Requirement (EAR) of zinc varies from 16% in households with full food security to 27% in those with very low food security ¹¹.  In Europe, the average intake of zinc is above the recommended amount.  However, certain vulnerable populations may benefit from including more zinc rich foods or supplements in their diet e.g. those on plant-based diets with little animal foods, the elderly ⁵.

Are there Health Risk of Excess Intakes?

Excessive amounts of zinc can cause nausea, dizziness, headaches, gastric distress, vomiting, and loss of appetite and chronic large doses of 50 mg of zinc or more can inhibit copper absorption and reduce immune function ⁹.  Excessive intakes from food sources are unlikely but may occur with excessive supplementation.  The IOM Tolerable Upper Intake Level for zinc is 40mg per day for adults.  EFSA has set the Tolerable Upper Intake Level (UL) for total daily zinc intake from all sources (diet and supplements) at 25mg per day for adults.  This level is based on the reduction of copper status ¹².   Lower limits are recommended for younger groups.

Is Zinc Supplementation Effective?

A 2024 Cochrane review ¹³ based on 34 randomised controlled trials in children and adults (15 prevention, 19 treatment) showed that compared with placebo, taking zinc preventatively may make little to no difference to whether a person catches a cold or to the duration or severity of the cold.   Taking zinc for treatment of an existing cold may reduce the duration but the authors were not confident of the quality of the result which they describe as low to very low.

The most common negative sides effects were irregularities in taste and stomach upset.  A recent review however supports a preventive role of zinc supplementation in reducing the incidence and burden of respiratory infections, particularly in children with recurrent disease and in zinc-deficient populations ¹⁴.

This article was published in March 2020 and updated on March 31, 2026.

Vitamin C is one of the most common nutrients that comes to mind when thinking about immune health.  It is a water-soluble vitamin that serves as a cellular antioxidant, which means it protects cells from reactive oxygen species and cellular damage ¹.  By protecting both skin barriers and immune cells from damage, vitamin C enables them to function properly.  It is required by cells from both the innate (general) and adaptive (specialised) immune system ².

The innate immune system is the body’s first line of defence.  When pathogens like infectious bacteria or viruses get into the respiratory tract or gastrointestinal system, the innate immune system responds by sending cells like neutrophils or macrophages to remove the threat.  These cells try to engulf the invading pathogen or create enzymes to destroy it.

The adaptive immune system specifically targets the pathogen and takes over from the innate immune system. It is often described as the ‘memory’ of the immune system.  Once exposed to a pathogen, the immune system can remember the identity of that pathogen for the future and quickly mount a defence specific to that pathogen.

Vitamin C promotes barrier function, supports the function of neutrophils, monocytes, and macrophages and the activity of NK cells.  It also has a role in the differentiation and function of T cells, especially cytotoxic T cells and in antibody production ¹.  This role has been recognised in an approved European Union health claim for vitamin C, stating that it “contributes to the normal function of the immune system” and is available to foods subject to condition within the EU ³.

Are there Recommended Intakes for Vitamin C?

Global daily vitamin C intake recommendations range from 40 to 110 milligrams per day, depending on region ⁴.  In the US, the Institute of Medicine’s (IoM) recommendations are 90mg per day for men and 75mg per day for women  ⁵.  In the EU, the European Food Safety Authority has established a Population Reference Intake of 110mg per day for adult men and 95mg per day for adult women ⁶.  Similarly, the Chinese Nutrition Society Reference Nutrient intake is 100mg per day for adult men and women ⁷.

What are the Dietary Sources of Vitamin C?

Vitamin C can be found in many fruits and vegetables, such as kiwis, oranges, peppers and broccoli.  The table below shows amounts of vitamin C found in commonly consumed foods.

Source: National Institutes of Health Vitamin C Fact Sheet for Health Professionals ⁸

What Happens with Vitamin C Deficiency?

About 53% of the global population have an inadequate intake of vitamin C ⁹, but the exact number varies depending on global region.  Inadequate intakes were more prevalent in men than women and in areas like South Asia.

Scurvy is a nutritional disorder caused by low vitamin C levels which manifests with varied symptoms affecting multiple organ system due to its role in connective tissue synthesis.  Although it is rarely seen, sporadic cases still occur.  In developed countries, it is mainly diagnosed in the elderly and malnourished individuals and is associated with alcoholism and poor dietary habit s¹⁰.

People who smoke or are exposed to second-hand smoke need more vitamin C in their diets because smoke increases the amount of vitamin C that the body needs to repair damage caused by free radicals ⁵.

Are there and Risks with Excess Intakes of Vitamin C?

In general, vitamin C has low toxicity, and high intakes of vitamin C do not cause serious adverse effects.  However, high doses of vitamin C can lead to diarrhoea, nausea, abdominal cramps, and other gastrointestinal disturbances ⁵.

There are some concerns surrounding high vitamin C intakes, such as the formation of kidney stones and excess iron absorption, but these are not generally considered a risk in healthy individuals. While EFSA did not establish an upper limit, the IoM Tolerable Upper Intake Level for vitamin C ranges from 400 to 2,000mg per day, depending on age ⁵.

What about Vitamin C Supplementation?

There is some evidence that vitamin C doses exceeding recommended daily values could have potential benefit.  A Cochrane review ¹¹ of clinical trials testing vitamin C’s effect on immune health found that regular supplementation (>200mg per day) did not influence how often participants got common colds but reduced the duration of cold symptoms.  A recent meta-analysis ¹² of trials which used doses of Vitamin C above 1g per day found a greater benefit on more severe measures of the common cold.

Severe Acute Respiratory Syndrome Coronavirus 2 , which is a respiratory condition, is marked by significant oxidative stress and an excessive inflammatory response that results in tissue damage of the respiratory system.  For this reason, there has been interest in combining antioxidants like vitamin C with antiviral and anti-inflammatory treatments to improve patient outcomes.  However, a recent review ¹³ suggests that further trials are necessary to determine optimal doses and conditions of use.

This article was first published in May 2022 and updated on March 24, 2026.

Although vitamin A is more frequently associated with vision, it plays multiple roles in supporting the immune system, including:

• • maintaining the integrity of skin and mucosal barriers that protect from pathogen invasion.
  • supporting the innate (general) immune system (e.g. regulating Natural Killer (NK) cell production, supporting phagocytic activity of macrophages).
  • supporting the adaptive (specialised) immune system (e.g. development and differentiation of Th1 and Th2 cells which direct the destruction of invading cells, B cell mediated antibody responses to antigen) ^{1, 2}.

There is an approved European Commission health claim for vitamin A, stating that it “contributes to the normal function of the immune system”, and is available to foods that meet defined criteria within the EU ³.

What are the Recommended Intakes of Vitamin A?

Vitamin A recommendations for adults vary by region:

• • China: the Chinese Nutrition Society Reference Nutrient intake (RNI) is 660mg per day for adult women and 770mg per day for adult men up to 50 years ⁴.
  • Europe: the European Food Safety Authority (EFSA) population reference daily intakes (PRI) are 650 micrograms for women and 750 micrograms for men ⁵.
  • United States: the Institute of Medicine (IOM) recommended dietary allowance (RDA) is 700 micrograms per day for women and 900 micrograms per day for men ⁶.

Where can Vitamin A be Found in the Diet?

Vitamin A in the diet comes from two sources: preformed vitamin A (retinol and retinyl esters) and provitamin A (carotenoids).  Preformed vitamin A is found in foods from animal sources, while provitamin A  are plant pigments that include beta-carotene, alpha-carotene, and beta-cryptoxanthin.  These provitamin A carotenoids are converted into vitamin A in the body, although conversion efficiency shows considerable variation and is influenced by the food source, an individual’s vitamin A levels, and the amount eaten ⁷.

Preformed Vitamin A or retinol is found in animal products mainly including liver, fish and eggs while provitamin A sources are generally found in colourful vegetables like carrots, sweet potato and peppers (See Table 1).

Some countries such as the US routinely add vitamin A to milk and margarine while some ready-to-eat cereals are also voluntarily fortified with vitamin A.  For this reason, it is important to use local information when calculating dietary intakes.

In Western diets, retinol accounts for nearly 65% of total vitamin A intake with carotenoids making up 35% of the total ⁸ but the contribution of carotenoids is higher in countries such as Southeast Asia and Africa where it can make up to 80% of the vitamin A intake ⁹.  Recent data shows that in China, vegetables are the greatest contributor to total vitamin A intakes ¹⁰.

Table 1. Food sources of Dietary Vitamin A ⁷

What are the Effects of Vitamin A Deficiency?

Vitamin A deficiency is a public health problem in more than half of all countries especially those in Africa and South-East Asia ¹¹.  The most severe effects of vitamin A deficiency are seen in young children and pregnant women in low-income countries, ranging from preventable blindness to a weakened ability to fight infections.  Vitamin A deficiency is a double‑edged cycle in which illnesses like diarrhoea and measles further deplete vitamin A levels in the body.

In areas of deficiency, routine vitamin A supplementation is recommended in infants and children up to 5 years of age ¹².  Other strategies include dietary based approaches, biofortification, and food fortification.  Even in developed countries, the importance of vitamin A in the very young is recognised, e.g. it is recommended that children in the UK aged 6 months to 5 years take a vitamin supplement containing vitamins A, C and D every day ¹³.

Are there Risks with Excess Intakes of Vitamin A?

As vitamin A is fat-soluble, it can be stored in the body, particularly the liver and excessive intakes can cause harm.  The US IOM set an upper limit of 3,000mg per day of pre-formed vitamin A for adult men and women including pregnant adults ⁴.  The EFSA have set the same upper limit for adults including women of child-bearing age, pregnant and lactating women and post-menopausal women.  Lower limits are recommended for younger groups ¹⁴.

In terms of the provitamin, beta-carotene, there is no indication that intakes from dietary sources are linked to adverse health effects.  However, smokers have been recommended to avoid consuming food supplements containing beta-carotene, and their use by the general population should be limited to the purpose of meeting vitamin A requirements ¹⁴.

What about Vitamin A Supplementation?

Vitamin A deficiency affects not only the growth and development of children but also increases susceptibility to infectious diseases including respiratory and gastrointestinal infections ⁸.

Across Asia, India and Africa, vitamin A supplementation has been associated with a lower incidence of diarrhoea and measles among children (low quality evidence) while all-cause mortality was also reduced with supplementation (high quality evidence) ¹⁵.

A 2024 Cochrane review showed that vitamin A supplementation did not prevent or reduce the duration of acute upper respiratory infections (URTIs) in children up to seven years of age in low to middle income countries ¹⁶.  However, this was based on a limited number of studies and more research is needed.

What is the Role of Vitamin D in Human Health?

Vitamin D, sometimes known as ‘the sunshine vitamin’, is a fat-soluble vitamin important for bone health, muscle function and the immune system ^1-4.  Vitamin D is also being investigated for its role in protecting against some chronic diseases including cardiovascular disease and type-2 diabetes ¹.

Vitamin D exists in two primary forms:

(i) vitamin D2 (ergocalciferol) which is obtained from plant and fungi sources that have been exposed to UV light.

(ii) vitamin D3 (cholecalciferol), found in animal-based products such as fatty fish, eggs and liver ³.

Both forms of vitamin D are biologically inactive when ingested and are absorbed in the small intestine.  They are transported to the liver and converted into 25-hydroxyvitamin D (25(OH)D), also known as calcifediol or calcidiol, followed by conversion in the kidneys into 1,25-dihydroxyvitamin D (1, 25(OH)2D), or calcitriol, which is the biologically active form used by the body (Figure 1) ³.  Studies have shown that vitamin D3 leads to a greater increase of serum 25(OH)D than vitamin D2 ⁵.

The ‘sunshine vitamin’ gets its name from the fact that it is also produced in human skin from 7-dehydrocholesterol when exposed to sunlight or more specifically, UVB rays.

Figure 1. Vitamin D Metabolism.  Image Source: Vitamin D Sources, Metabolism, and Deficiency: Available Compounds and Guidelines for Its Treatment

Functions

Research shows that vitamin D plays a significant role in bone health, muscle health and the immune system:

1. 1. Bone health: Vitamin D is a critical regulator of calcium absorption.  In its active form, 1,25(OH)2D, it interacts with the vitamin D receptor (VDR) in the small intestine resulting in an increase in calcium and phosphate absorption ².  However, calcium homeostasis is primarily regulated to maintain serum calcium within a narrow range for metabolic reasons with the parathyroid gland, bone, intestine, and the kidney working together in this role ⁴.  Chronic vitamin D deficiency that results in an increase in parathyroid hormone leads to increased bone resorption, compromising the structure of the skeleton and increasing the risk of fracture thus vitamin D sufficiency is important to optimise skeletal health ⁴.
   2. Immune health: Vitamin D plays a crucial role in regulating both the innate and adaptive immune responses.  The expression of VDR in many different immune cells has been well demonstrated ⁶.  It modulates the activity of immune cells, such as B cells, T cells, and antigen-presenting cells, and promotes a balanced immune response.  Vitamin D deficiency is associated with an increased risk of hospitalisation for respiratory tract infections ⁷ and supplementation has been shown to boost antigen-specific immunity in older adults with sub-optimal vitamin D status ⁸.  Genetic variation in the VDR genes has also been linked to Vitamin D deficiency and the development of autoimmune disease ⁶.
   3. Muscle function: The identification of a VDR in skeletal muscle cells, along with the strong association between vitamin D deficiency, muscle atrophy, and sarcopenia, suggests an important role in muscle function ⁹.  Proposed mechanisms include modulation of protein synthesis, mitochondrial metabolism, and energy production, which may influence performance.  However, the effects of vitamin D3 supplementation on muscle mass, strength, and physical performance remain debated, with conflicting findings.  Meta-analyses of randomised controlled trials in athletes have not shown conclusive benefits, highlighting the need for further research ^10,11.  In contrast, supplementation has been associated with improved muscle strength in postmenopausal women ¹².  Interpretation of trial results should consider whether populations have insufficient or sufficient vitamin D status and whether any supplementation used has increased 25(OH)D levels sufficiently as these factors may influence outcomes ¹³.
   4. Mental health: Emerging evidence suggests a link between vitamin D and mental health – its neuroprotective properties may contribute to its role in mental wellbeing, reducing neuroinflammation, supporting serotonin synthesis, and improving brain plasticity ¹⁴.  Recent meta-analysis suggests no benefit of supplementation in healthy individuals ¹⁵ but potential effects on depressive symptoms in those with major depressive disorder or with milder, clinically significant depressive symptoms ¹⁴.  However, more high-quality research trials are needed.
   5. Other Potential Roles: Vitamin D has other roles in the body, including modulation of cell growth, neuromuscular function, and glucose metabolism ¹⁶.  Ongoing research is also exploring the potential benefits on other health conditions including heart disease, diabetes, and musculoskeletal diseases like multiple sclerosis ¹⁷.

In European Union countries, approved health claims are available for the role of Vitamin D in supporting a wide range of functions including maintaining normal bones and teeth, muscle and immune function as well as supporting absorption of calcium and phosphorous subject to conditions.  In China, claims relating to the health of bones and teeth, and the absorption and utilisation of calcium and phosphorus are also available for vitamin D containing foods subject to conditions.

Recommended Intakes

In some countries, national dietary reference tables can lag behind updated clinical practice or more recent Vitamin D supplementation policies.

• • United States:  The Institute of Medicine (IOM) Recommended Dietary Allowance (RDA) for vitamin D is 600 IU (15 micrograms) daily for adults aged 19–70 and 800 IU (20 micrograms) daily for adults over 70 years, assuming minimal sun exposure ¹⁸.
  • Europe:  The European Food Safety Authority (EFSA) has set an adequate intake at 15 micrograms per day for healthy individuals over one year of age including pregnant and lactating women to ensure the majority of the population will achieve a serum 25(OH)D concentration near or above the target of 50 nmol/L ¹⁹.
  • China: The Chinese Nutrition Society have set a daily Reference Nutrient intake of 400 IU (10 micrograms) for adults aged 18-50 and 600 IU (20 micrograms) for adults over 50 years ²⁰.

Dietary Sources

Foods rich in vitamin D include oily fish (e.g., salmon, mackerel, and sardines), egg yolks, and offal.  However, sources are limited and there are high levels of inadequacy of vitamin D intake globally ²¹.  In some countries, fortification of staple food (e.g., milk, margarine, cereals) is used to increase vitamin D intake but these policies differ by region and are often voluntary, leading to variable dietary contributions.  For this reason, local food composition data and values should be used when estimating intakes.  For example, milk is frequently quoted as a source of vitamin D but only when vitamin D fortified milk is available.  Liver provides vitamin D but is not widely consumed and is not recommended during pregnancy because of its high vitamin A content ²².  Among plant-based options, mushrooms exposed to sunlight or UV radiation can supply vitamin D2.

Vitamin D – Beyond Food

The level of 25(OH)D in populations varies geographically due to latitude, skin pigmentation, sun exposure, diet, and supplement use.  While endogenous production of vitamin D from sun exposure is also a potential source, recommendations to limit sun exposure to prevent skin cancer and limited sunlight in higher latitudes during winter mean that it cannot be relied upon as a source.

In many countries, vitamin D supplementation is recommended either during winter or throughout the year for more vulnerable populations (e.g. pregnant women, elderly, those with darker skin) ^23-25.  The Endocrine Society also recommend supplementation for children aged 1 to 18 years and those aged 75 years and older as well as pregnant women and those with high-risk prediabetes ²⁶.

Vitamin D Deficiency

The concentration of 25(OH)D in blood serum is currently the main indicator of vitamin D status as it reflects vitamin D produced through both sunlight and from the diet.  There is no universal agreement on the threshold for vitamin D ‘deficiency’.  However, there is widespread acknowledgement of vitamin D deficiency using the most conservative 25(OH)D threshold of < 25/30 nmol/L, in both low- and high-income countries ¹.  Depending on the world region, the prevalence of serum 25(OH)D below this threshold  ranges from ~5 to 18% and 24 to 49% for levels below 50 nmol/L ²¹.

Vitamin D deficiency in toddlers and young adults can cause rickets and slow brain development.  Deficiency in adults causes osteomalacia (brittle bones) increasing susceptibility to fractures.  Confirmed vitamin D deficiency is typically treated with high-dose supplements for a limited number of weeks followed by a maintenance dose ²⁸.

Excess Intakes

It is important to remember that as a fat-soluble vitamin, vitamin D can be stored in the liver and excessive amounts should be avoided.  An upper daily limit of 100 micrograms from all sources has been set in the US by the IOM for those 9+ years ¹⁸ while an upper daily limit of 50 micrograms for children and 100 micrograms for adults has been recommended by the EFSA ²⁷.

In Closing

Ongoing research continues to explore vitamin D’s potential benefits further refining our understanding of its role in human health.  While vitamin D is essential, further research is needed to fully understand its role in various health conditions and to establish clear guidelines for supplementation.

This article was originally published on March 18, 2025, and updated on March 3, 2026.[/vc_column_text][/vc_column][/vc_row]

Anyone with a teenager is no stranger to the wave of curious trends that frequently emerge from social media, many of which revolve around the term ‘maxxing’.  However, the latest term ‘fibremaxxing’ has caught the attention of social media followers and the food and nutrition community alike.

Protein has been such a huge trend that it has been difficult for other nutrients to get attention.  But the world of social media moves quickly and within the last year there has been a wave of ‘fibremaxxing’ clips flooding social platforms, with influencers of all ages sharing their favourite ways to boost daily fibre intake.

As ever, these clips range from the sensible and inspiring through to the more extreme.  Some engage in a type of ‘gamifying’ of fibre to ‘max out’ with the message becoming more about the game than health.  But at its core, the message about fibre is grounded in evidence linking higher intakes to reduced risk of cardiovascular disease and several cancers^1,2, especially colorectal cancer, as well as type 2 diabetes³.

The Good and Not-So-Good of ‘Fibremaxxing’

Table 1 summarises the pros and cons of ‘Fibremaxxing’.  There is a significant gap between fibre recommendations and actual intakes in most western countries so any focus on increasing fibre through cereal-based wholegrain foods, fruit and vegetables, pulses, legumes, nuts, and seeds, is to be welcomed.  However, if fibre intake is low, increasing consumption is best done gradually to avoid issues like bloating, cramping, constipation or diarrhoea.

Table 1.  ‘Fibremaxxing’ Pros and Cons

Many types of insoluble fibre also bind water in the large intestine and an increase in fluid intake is needed for the fibre to do its work properly.  Where dietitians and/or nutritionists have weighed in on this social media trend, these caveats are highlighted.

Counting fibre intake may initially help consumers identify their own fibre gap but this is best used short-term until healthy choices and habits become embedded.  Getting caught up in obsessive tracking of fibre intake rather than enjoying a balanced diet is not the goal.

On the positive side, many ‘fibremaxxing’ posts are useful in calling out the benefits of fibre beyond ‘keeping you regular’.  Previous research has shown that if individuals are regular in their bowel habits, they don’t feel the need to worry about fibre intake⁴, so it is important to clarify that regularity alone shouldn’t be the only goal.  Inspiring social media posts that include tasty high fibre recipes can also help dispel the myth of fibre as ‘bland and boring’.

Some ‘maxxers’ attempt to ‘fix’ their fibre gap with the use of supplements.  While supplements have their place, particularly if constipation is the issue⁵, the benefits observed from prospective cohort studies are based on consuming a diverse range of dietary fibres.

The good news is that ‘Fibremaxxing 2.0’ is on its way in 2026, according to Mintel, with consumers shifting from simply maximising intake to consuming a variety of fibres⁶.  This is a positive progression of the trend, reflecting the science which shows that a diversity of sources is likely to be of most benefit.

How Much Fibre is Enough?

Fibre recommendations vary around the world but in general adults should aim for between 25-30g per day^3,7,8, with fibre intakes for children and younger teens being lower and in proportion to their energy intakes.  The US daily fibre recommendations from the Dietary Guidelines for Americans 2020-2025 are 22–28g for adult women and 28–34g for adult men, varying by age⁷.

Both the World Health Organisation³ and European Food Safety Authority (EFSA)⁸ recommend a minimum of 25g per day for adults based on normal laxation rather than a wider range of health benefits.  In South Africa and India, recommended fibre intake ranges can be as high as 38-40g per day⁹.  But conversations about “optimal” fibre intakes shouldn’t distract from the bigger issue: that most people aren’t getting enough in the first place and this needs to be addressed (Figure 1).

Figure 1.  A fibre gap exists in many countries^7,10-17

Diversity of Dietary Fibres

With its focus on a single fibre target, dietary recommendations may suggest that it is all about quantity, but the term dietary fibre covers a wide range of complex structures with different mechanisms of action.  Fibres that are poorly fermentable, e.g. wheat bran fibre, help to decrease transit time in the gut promoting good bowel function¹⁸.

Fibres that are more fermentable act as a food source for the gut microbiota and produce metabolites which can be beneficial to health, e.g. short-chain fatty acids.  Some fibres exert health benefits even before reaching the large intestine by slowing down the absorption of glucose¹⁹.

Emerging research shows that even small differences in the structure of the same fibre can create very different metabolic “fingerprints” in the gut²⁰, which could one day help target health benefits, with more precise recommendations for different types of fibre.  But for now, the smartest approach is simply to eat a wide variety of fibre containing foods²¹.

Harnessing the ‘Fibremaxxing’ Movement

Fibre Innovation for Food Industry

• • Look at the overall nutritional profile when considering fibre fortification.  With increasing nutrition literacy, consumers are savvy about products that offer a ‘health halo’ and question the levels of other less favourable nutrients including added sugars, saturated fat, and salt.  Manufacturers aiming to make fibre claims should therefore also assess whether reformulation of other nutrients including saturated fat, sugars and/or salt is needed and/or address portion size offerings.
  • Fibre can be leveraged to replace sugar or fat or to improve structure in gluten-free products and at 2 kcal/g (values may vary according to local regulations) it can contribute to a reduced energy value when replacing carbohydrates (4 kcal/g) or fat (9 kcal/g).
  • Consider ‘upcycled’ sources of fibre that help reduce food waste, e.g. brewer’s grain.  Any additional reasons to enrich with fibre, such as an improved environmental footprint or offering technical functions could offer an alternative way to justify any costs associated with fibre enrichment.
  • Consider tolerance and format. Isolated dietary fibres are tolerated differently and have been well described²².  Tolerance can also depend on the food format – whether the fibre is delivered in a drink, a solid food, or within a particular matrix – so consumer trials are often essential.  Manufacturers face a real balancing act: adding a smaller, well-tolerated amount of fibre may only achieve a “source of fibre” claim, while adding enough to reach a “high in fibre” claim may risk digestive discomfort and reduce repeat purchase.  In many cases, combining different fibres may offer a better solution by improving both tolerance and functionality.  Clear communication of recommended serving sizes is also key to managing expectations and supporting a positive consumer experience.
  • Check for any allergen considerations, e.g. wheat derived fibre.

Recommendations for Healthcare Professionals

• • Fibre has been waiting a long time for its moment, and as interest in ‘Fibremaxxing’ grows, the responses from healthcare professionals need to be positive and constructive rather than focused on dismissing influencers – though some of the more extreme claims will inevitably need correction.  When a patient is active on social media and their healthcare provider isn’t, recommending reputable suitably qualified dietitians or nutritionists online becomes especially important.
  • Equally, it is worth bearing in mind that newer patients who are coming through with digestive complaints may well have been overdoing this trend and therefore worth exploring any recent changes in their diet.
  • There is also a need for more effective public health messaging that offers clearer, more actionable guidance on the frequency, quantity, and quality of fibre-rich foods.  For example, Australian researchers²³ found that consumers responded better to specific recommendations – such as “consume legumes once per day” and “eat more than half of your grain foods from whole grain choices” versus more vague statements.  The recent 2026 US Dietary Guidelines for Americans recommends prioritising fibre-rich whole grains (2 – 4 servings per day)²⁴.

In Summary

‘Fibremaxxing’ may have emerged from yet another social media trend, but its value should not be ignored as it represents a long-overdue shift toward recognising the essential role fibre plays in long-term health.

The excitement surrounding high-fibre recipes and inspiring food swaps can be a powerful driver of dietary change, but the trend works best when twinned with evidence-based guidance, gradual increases in intake, and a focus on fibre variety.

For consumers, this moment offers an opportunity to rethink what fibre looks like in everyday eating – not as a bland add-on, but as a naturally rich element of wholegrains, legumes, nuts and seeds, fruits, vegetables, that can support health far beyond regularity.

For industry and healthcare professionals, it is a reminder that meeting people where they are, with clear messaging and products that prioritise both nutrition and enjoyment, will be key to closing the persistent fibre gap.

If the ‘Fibremaxxing’ trend continues to evolve towards a more balanced perspective, rather than extremes and quick wins – it has the potential to do what few nutrition fads achieve: create meaningful, sustainable improvements in public health.

Disclaimer: This article should not be considered as medical advice.  For personalised health guidance, consult a qualified healthcare professional.

In the past number of years, consumer demand for natural, plant-based ingredients to support health has surged, a trend amplified by public health events such as the global COVID-19 pandemic.  During these periods, elderberry became a leading ingredient in the immune-support supplement category, with consumers seeking natural alternatives to support respiratory health ³.

This success in the supplement sector has since resulted in its expansion into the broader functional food and beverage industry ⁴.  Elderberry extracts are now increasingly incorporated into products such as flavoured beverages, snack bars, yogurts, and wines ^5-7, valued not only for their potential health benefits but also for their unique flavour profile and natural colouring capabilities.

Key Varietals

For the food and nutraceutical industries, three subspecies of Sambucus nigra L. are of primary interest:

• • • Sambucus nigra ssp. nigra (European Elderberry): Native to Europe, North Africa, and parts of Asia, this is the most extensively studied and commercially cultivated subspecies.
    • Sambucus nigra ssp. canadensis (American Elderberry): Native to a large portion of North America, this subspecies is gaining significant commercial attention because it may confer greater stability during processing compared with its European counterpart.
    • Sambucus nigra ssp. cerulea (Blue Elderberry): Native to western North America, this subspecies is distinguished by its ecological resilience, including notable drought and fire resistance, making it a sustainable crop option in challenging climates.

The foundational nutritional value of elderberry provides a complex matrix of proteins, lipids, and fibre ².  A thorough understanding of the nutritional and phytochemical composition of elderberry is essential for its effective application as a functional ingredient.  The distribution of these compounds varies significantly across different parts of the plant.

The Phytochemical Matrix

Not only are elderberries good sources of vitamins and minerals, but they also have an extensive and complex phytochemical composition ^4,8.  Phytochemicals form the cornerstone of elderberry bioactivities, responsible for its antioxidant properties, vibrant colour, and many of its health benefits.  The concentration and profile of these compounds vary dramatically depending on the elderberry subspecies, plant part, and growing conditions ^2,4.  The types of phytochemicals found in elderberries include flavonoids, anthocyanins, and carotenoids among others.

Anthocyanins, Flavonols, and Other Flavonoids
Anthocyanins are responsible for the characteristic deep purple-black colour of elderberries and are central to their market identity as an immune-supporting ingredient ^1,2.  Quantitative analysis reveals significant variation among subspecies where the European Elderberry contains the highest levels of anthocyanins, followed by the American Elderberry, whereas Blue Elderberry has the lowest anthocyanin content.  A noteworthy distinction of the American Elderberry is its high concentration of acylated anthocyanins, which can enhance pigment stability against degradation from heat and light, a highly desirable trait for food and beverage applications.

Beyond anthocyanins, elderberry is a rich source of other flavonoids, particularly flavonols, which contribute significantly to its overall antioxidant and anti-inflammatory capacity.  The flowers and leaves are often more concentrated sources of these compounds than the berries.

Carotenoids and Tocopherols
Elderberries are also rich in carotenoids and tocopherols, with a distribution that is highly specific to the plant part.  Berries are an exceptionally potent source of the carotenoids Lutein and Zeaxanthin, which are recognised for their role in eye health.  In contrast, the leaves are the exclusive source of other powerful antioxidant carotenoids, Astaxanthin and Canthaxanthin.  Furthermore, leaves are the primary reservoir of α-tocopherol, the most biologically active form of vitamin E.  Regional variations are also pronounced, with studies showing that samples from southern climates may accumulate higher levels of tocopherols.

Bioactivity and Health Benefits 

The rich and diverse phytochemical profile of the elderberry translates into a broad spectrum of potential bioactivities ^1-5.  Figure 1 outlines the potential benefits of Elderberries and the way in which these are mediated through bioactive compounds have been proposed ⁹.

Figure 1. Proposed Potential Health Benefits of Elderberry ⁹.

Potential Antioxidant Activity
A foundational mechanism underpinning many of the elderberry health benefits is its potent antioxidant capacity ^1,10.  The antioxidant effects are multifaceted including mechanisms such as direct free-radical scavenging and metal chelation, which position elderberry as a potential effective natural antioxidant ingredient.  Extracts from the flowers, berries, and leaves all demonstrate significant ability to neutralise harmful free radicals and mitigate oxidative stress, which is a key driver of ageing and chronic disease.

Anti-Inflammatory and Immunomodulatory Effects
The most well-known and commercially significant application of elderberry is for immune support, particularly in the context of respiratory health ³.  Its efficacy is rooted in anti-inflammatory and immunomodulatory activities.  Elderberry extracts have been shown to modulate the immune response by inhibiting the production of pro-inflammatory mediators.  This action helps to balance the immune response, preventing excessive inflammation that can cause tissue damage during an infection ^10,11.

Neuroprotective Properties
An emerging area of research is the neuroprotective potential of elderberry.  The bioactive compounds in elderberry can cross the blood-brain barrier and exert protective effects directly within the central nervous system ⁵.  In vitro and in vivo studies have shown that elderberry extracts and their constituent polyphenols can protect neuronal cells from oxidative damage, reduce neuroinflammation, and improve cognitive and motor function in animal models.

Application in Functional Foods and Beverages

The application of elderberry is twofold: as a natural additive for colour and preservation, and as a core functional ingredient to deliver potential health benefits ².

Elderberry as a Natural Additive: Colour and Preservation
In response to strong consumer demand for “clean-label” products, elderberry serves as an excellent natural alternative to synthetic additives.  The final colour is pH-dependent, exhibiting red shades in acidic environments (e.g., yogurts, fruit beverages) and shifting towards blue and purple in more neutral or alkaline conditions ^5,12.

Beyond colour, elderberry’s potential antioxidant properties make it a valuable natural preservative.  By inhibiting lipid and protein oxidation, elderberry extracts may extend the shelf-life and maintain the quality of perishable foods.  This has been demonstrated effectively in meat products, where encapsulated elderberry extract was shown to significantly delay the oxidative processes that lead to rancidity and discolouration in beef burgers ¹³.

Formulation with Elderberry as a Functional Ingredient
The primary driver for incorporating elderberry into food products is its status as a functional ingredient, capable of imparting health benefits beyond basic nutrition ¹⁴.  Its versatility allows for its use in a wide range of food matrices.

In the dairy sector, elderberry has been successfully incorporated into products such as yogurt and kefir ^15,16.  Studies have shown that the addition of elderberry juice, puree, or pomace powder increases the product’s total phenolic and anthocyanin content, thereby boosting its antioxidant capacity.  However, formulation requires careful consideration of texture; direct addition of juice can decrease viscosity, while using restructured or encapsulated forms can maintain or even improve consistency and has been shown to lead to higher consumer acceptance.  The stability of the bioactive compounds is also a key factor, with evidence showing that elderberry anthocyanins can remain stable during the shelf-life of yogurt ¹⁵, particularly when protected within a restructured matrix.

In bakery applications, elderberry adds both functional and nutritional value ¹⁷.  The incorporation of elderberry powder into gluten-free wafers has been shown to increase the final product’s flavonoid and mineral content while also improving batter properties by reducing delamination ¹⁸.  Similarly, adding elderberry juice to croissants or fermented elderberry to bread enhances their antioxidant capacity and bioactive compound content without negatively impacting nutritional quality.  Fermentation has been shown to enhance the bioactivity of the elderberry before its incorporation, leading to a final product with a higher phenolic content and an extended shelf-life.

The meat industry represents a significant opportunity for elderberry application.  Due to the high susceptibility of meat to oxidative degradation, the antioxidant properties of elderberry are particularly valuable.  A study on beef burgers demonstrated that an encapsulated elderberry extract acted as a highly effective “meat extender,” significantly delaying both lipid and protein oxidation more effectively than synthetic antioxidants during refrigerated storage ¹³.  This not only extends shelf-life but also adds a health-promoting, clean-label ingredient to the product.

Another novel application is the use of elderberry vinegar as a marinade or spray for grilled meats, which has been shown to inhibit the formation of harmful polycyclic aromatic hydrocarbons by over 80% ¹⁹.

A central challenge in utilising elderberry is the need for thermal treatment to ensure safety conflicts with the desire to preserve heat-sensitive bioactive compounds.  Raw elderberries should not be consumed because certain parts contain cyanogenic glycosides (CNGs) ², which must be degraded through heating to render the product safe for consumption.  Therefore, it is critical that elderberry products intended for consumption must undergo a heating step.

Considerations
As consumer interest in more natural, proactive health products continues to grow, science-backed, botanical ingredients, such as elderberry, have an opportunity to take a further foothold in the health and wellbeing market.  While future studies are needed to further confirm the efficacy of elderberries and how they mediate immune benefits, the research has shown that, at a minimum, elderberry is a safe option with the botanical showing no evidence of over stimulating the immune system.

The functional potential of an elderberry ingredient is not uniform. Factors such as climate, soil type, and genotype directly influence the concentration of key bioactive compounds.  Therefore, sourcing elderberry cannot be a simple commodity-based decision. It requires a strategic approach that aligns the specific phytochemical profile of a given source with the desired health benefit and final product application, moving beyond a generic “elderberry extract” to a precisely characterised, high-performance functional ingredient.

Vitamin B12 is a water-soluble vitamin, also known as cobalamin, this cannot be made in the body and needs to be ingested through food, supplements, or medication. It is essential for red blood cell formulation, keeping your nerve and brain function healthy, production of DNA, and maintaining cell metabolism.

Vitamin B12 is absorbed by the stomach with the help of a protein named intrinsic factor which is a glycoprotein, this protein substance binds to the B12 molecule and aids in the red blood cells absorbing it. Excess B12 can be stored in the liver for future use or excreted through urine.

With more consumers choosing plant based diets or veganism, meeting essential B12 requirements can sometimes be challenging. Unlike many essential vitamins that can be readily sourced from plants, Vitamin B12 is primarily found in animal products, making it difficult for vegans and vegetarians to obtain adequate amounts of through their diet alone. Understanding the role of Vitamin B12 in the body is crucial for maintaining optimal health and wellness.

How much Vitamin B12 do we need and where do we find it?

The Recommended Daily Intake (RDI) of Vitamin B12 is 2.4 micrograms daily for adults and children over the age of 4 years old. Those who are vegetarians, vegans, pregnant and breastfeeding may need to increase their intake slightly or could run the risk of deficiency. Older adults, those with intestinal issues, those who are Pregnant and Breastfeeding, Infants of Vegan and Vegetarian mother’s, Vegetarians and Vegans are all at higher risk for developing a deficiency in B12. It was also reported that 1 in 10 adults over 75 years, and 1 in 20 adults aged between 65-74 years had a deficiency of Vitamin B12.

B12 can naturally be found in foods of animal origin such as meat, fish, eggs and dairy products, specific examples include animal liver and kidneys, beef, tuna, salmon, broccoli, peas, and brussels sprouts. It can also be added to fortified nutritional yeasts and fortified breakfast cereals. In cases of Vitamin B12 deficiency, it can also administered in the form of supplements and injections.

What happens if we do not have enough Vitamin B12 in our diets?

Insufficient intake of Vitamin B12 can lead to deficiency. This can occur when Vitamin B12 levels in the blood drop, resulting in metabolic abnormalities. These abnormalities lead to the onset of physical and psychological symptoms, such as as nausea, constipation, diarrhoea, metal health issues, low red and white blood cell count, deterioration in walking, vision impairment, and fatigue. The long-term symptoms of include, pernicious or macrocytic anemia, heart conditions, temporary infertility, and issues with the nervous system. If untreated, this can then result in the development of pernicious or macrocytic anemia.

Pernicious anemia is when the immune system attacks the healthy cells within the stomach which results in a lack of absorption of Vitamin B12 in the body. Macrocytic anemia is when the body produces abnormally large blood cells that lack the required nutrients and do not function as they should. Vitamin B12 deficiencies are treated by taking supplements or Vitamin B12 injections (hydroxocobalamin) depending on GP advice and the severity of your deficiency. Supplements/injections may be required long-term if symptoms persist. However, a beneficial start to improving Vitamin B12 levels in the body is to consume a high about of Vitamin B12 rich foods.

The preventative steps we can take to avoid a Vitamin B12 deficiency is to consume foods rich in B12, as listed above. Additionally, a deficiency in Vitamin B12 may not always be due to an inadequate dietary consumption of foods containing B12, it is possibly due to the lack of the intrinsic factor, this is most common among older adults which is associated with an autoimmune disease called pernicious anemia.

How Does Vitamin B12 interact with other Vitamins?

It should be noted that taking Vitamin C in close proximity to Vitamin B12 foods/supplements should be taken with caution as Vitamin C can reduce the amount of B12 in the body, therefore spacing out the consumption of both vitamins is recommended.

Vitamin B12 and Folate (B9) work together to produce a compound that aids in immune functionality, and red blood cell formulation. Therefore, consuming a balanced amount of foods containing B12 and Folate is beneficial for the overall health. It should also be noted that consuming over 1mg of folic acid daily can mask the symptoms of a Vitamin B12 deficiency.

Vitamin B12 Production Process and Sustainability:

For those who can’t get enough Vitamin B12 through their diet, supplementing B12 may be necessary. Supplemental Vitamin B12 is produced commercially through a bacterial fermentation process, taking up to two weeks from beginning to final product. It is one of the most complex vitamins to produce beginning with bacteria growing in large vats holding over 100,000 liters, this amount still only produces a small yield of final product. It is not a sustainable process and can be harmful to the environment as it traditionally uses cobalt and cyanide, and the harmful and hazardous surplus is expensive to be disposed of to ensure environmental health measures are not affected.

Research from the University of Kent took place in 2023 to develop a sustainable manufacturing process for Vitamin B12. The team manufactured a strain of E-coli that contains a smaller amount of cobalt that is then absorbed during the production process and there is no surplus cobalt left to be disposed of, therefore it is not a high health or environmental risk and is less of an expense. This is a step in the right direction and is a template that other bacterial processes could benefit from and become more sustainable in the future.

Vitamin B12 plays a vital role in the functionality of a healthy body. Ensuring a holistic diet to include certain meats, dairy products, fish, and certain vegetables will help reduce the risks that come with its deficiency. Increasing the availability of knowledge surrounding the importance of Vitamin B12 and its sources would advocate for a better understanding among individuals. This in turn will reduce the risks associated with lower consumption of this vital vitamin. Additionally, looking towards the future of supplemental B12 production, a long-term plan to formulate a universal sustainable production process of Vitamin B12 would reduce the harmful environmental impact and costs all while benefitting those with a deficiency.