Healthy Aging | Nutrition for Longevity – Kerry Health And Nutrition Institute

Active Ageing – Why is Protein So Important?

Erik Bauer — Tue, 09 Mar 2021 17:03:13 +0000

Read Part 2 of this article: Active Ageing – How Can We Optimise Plant Proteins?

Although the average global life expectancy is now over 70 years, the focus for many people today is not “how old can I live to be?” Instead, the most important question has become “will I be able to do the things I want to do when I am older?” Retaining muscle mass is key for active ageing because it allows us to do the day-to-day activities we want to do, as well as protects us from falls and the associated injuries that can result.

Protein’s role in muscle health might be more than you think

Leucine and insulin are “switches” that activate protein synthesis

Most people think of protein, or the amino acids in protein, as the “building blocks” that our body uses to make muscle, but some amino acids have unique roles in metabolism. Scientists have shown that there is a metabolic “switch”, called mTOR, that signals new muscle production when it’s activated. Think of it as the body’s way to regulate creation or upkeep of muscle by promoting growth mainly when fuel or building blocks are plentiful (protein-rich food), or when the body senses an external need for muscle growth or repair (exercise).

Leucine, an essential amino acid that we must get through our diet, plays an important role in turning this “switch” on. When present alongside insulin, which is a hormone that has a key role in telling the body that fuel is plentiful, leucine will activate the mTOR “switch” to allow for creation of new and upkeep of existing muscle protein (Columbus et al., 2015; Ham et al., 2014).

Our ability to activate muscle growth and repair decreases as we age, leading to a loss in strength and ability to perform physical activities

It has been shown that as we age, our ability to stimulate this mTOR complex is reduced which, in turn, reduces our ability to repair and replace protein in muscle tissue. This is thought to be because of a concept called anabolic resistance, which refers to a decreased sensitivity to insulin throughout the body as we get older (Yoon, 2017).

This helps explain why muscle mass gradually starts to decrease as we get older. After the age of 50, approximately 1% of muscle mass is lost annually.

We lose up to 40% of the cross-sectional area of our muscles between the ages of 20 and 60 years; this continues each year thereafter as a result of developing resistance to protein synthesis stimulation (Vandervoot 2002).

Cross-sections of muscle showing the impact physical inactivity can have on muscle mass during ageing. Taken from the webinar Active Ageing: Distinct Nutrition, Distinct Innovation? McLeod M., Breen L., Hamilton D.L., Philp A. (2016) Live strong and prosper: the importance of skeletal muscle strength for healthy ageing. Biogerontology 17(3):497-510.

A loss of between 30-50% of our total muscle mass by the age of 80 often translates into a severely reduced ability to perform day-to-day activities like climbing stairs, standing, or walking.

Increased protein intake can counteract age-related muscle loss

Increased protein intake may be able to counteract this decreased insulin sensitivity that comes with ageing, which is called anabolic resistance. For young children and adults (< 30 years), the mTOR complex is mostly stimulated by insulin, meaning less leucine (and thus protein) is required to be consumed in each meal (approx. 1g leucine per meal). As individuals age, the sensitivity of the mTOR complex to insulin reduces and this means that more leucine (2.5g per meal) is required to sufficiently stimulate muscle protein synthesis. This means older adults need to consume more protein than younger adults and children to maintain muscle mass (Yoon, 2017). According to a study by Moore et al. in 2014, older adults need 68% more protein to maximize protein synthesis (i.e. activate mTOR).

The dietary recommendation for protein intake from the World Health Organisation is 0.8g per kilogram of body weight (BW) per day, which is equivalent to around 64g per day for the average male and 55g per day for the average female. This amount is thought to meet the requirements of healthy adults, but there is scientific debate about whether this recommendation should be greater in older adults.

In a study by Campbell et al. (2001), 10 healthy male individuals, aged between 55-70, were fed the Recommended Daily Allowance (RDA) for protein (0.8g/kg BW) over a 14 week period and the results showed that all subjects, bar one, displayed a loss of muscle in their mid-thigh muscle zones. It was concluded that the RDA may not be adequate for the metabolic and physiological need of virtually all ageing people.

How much more protein is needed?

As a result of studies like the one mentioned, groups such as the European Society for Clinical Nutrition and Metabolism (ESPEN) and the International PROT-AGE Study Group have proposed new recommended requirements for protein intake (Bauer et al., 2013; Deutz et al., 2014). They concluded that for healthy individuals over the age of 65 the recommended dietary protein intake should be increased to 1.0 – 1.2g protein/kg BW.

This would be an increase of 25-50% in the total amount of protein needed in a day for older adults, equivalent to daily intakes 80-93g per day for the average male and 69-83g per day for the average female.

Results from clinical studies have supported these higher recommendations with one such study by Houston et al. (2008) showing that ageing adults who had a daily protein intake of 1.1g protein/kg BW lost 40% less muscle over the course of three years when compared to those who were consuming the RDA value of 0.8g/kg BW.

Opportunity: increase both protein intake and frequency

Despite needing more protein at ages 50+, people generally tend to consume less protein as they age. For example, in the United States, men over 70 years old tend to eat around 20% less protein per day than males who are 19-50 years old.

To help people stay active and independent as they age there’s an opportunity for the food and beverage industry to find ways to add protein into the diets of healthy agers. The amount of leucine needed to activate muscle growth and repair is thought to be equivalent to around 25-30g of high quality protein at a single eating occasion.

This means planning meals, or creating foods and beverages, with 25-30g of protein if they are meant to be consumed alone (e.g. meal replacement beverages), or 10-15g of protein if they are intended to be consumed at a meal or with other foods, is one way to improve muscle health. Choosing flavors and language that appeal specifically to active agers is also important.

Turn the “switch” on multiple times per day – opportunities for breakfast, snacks, and lunch

The more times the mTOR “switch” is activated per day via consuming protein, the more likely we are to grow or retain our muscle mass (Layman 2009). Many people consume low amounts of protein early in the day, such as at breakfast, mid-morning, and lunch, and consume a protein-heavy evening meal. This means that muscle growth is likely to be only activated once per day. By shifting protein toward the early parts of the day, we can activate this “switch” more times per day, leading to a greater retention of muscle through diet alone.

For some people, this doesn’t necessarily mean consuming more total protein in a day is required. Instead, it can be effective to redistribute protein intake to be more equal across the dayparts. Adding protein to breakfast foods and mid-morning snacks is a great way to promote more protein intake throughout the day. This could include fortifying common breakfast foods like oatmeal, cereals, yoghurts, etc., or creating new foods or beverages to consume alongside a meal.

Maintaining Healthy Muscles and Mobility in Older Adults During Social Distancing

Erik Bauer — Thu, 09 Apr 2020 14:31:35 +0000

People aged 60 years and over are a vulnerable group with respect to the recent COVID-19 pandemic. Measures to protect older people from contracting the virus include personal hygiene practices, social distancing and staying at home. These are extraordinary measures, and while it is vital for public health that these are adhered to, they can have cascading effect on other aspects of physical, emotional and mental well-being. This article is the first in a 3-part series covering the impact of social isolation on older adults, addressing the key challenges with solutions for maintaining holistic well-being.

‘Deconditioning’ and the potential loss of muscle mass and strength during social isolation

Currently many are being advised to “stay at home” and to minimise our physical contact with others. Following this advice is the best thing we can do to protect our health and the health of others. For many people, staying at home may lead to a reduction in time spent walking and engaging in other physical activities. Even relatively short periods (~2 weeks) of very low physical activity / low daily step count (<2,000 – 3,000 steps per day) are known to adversely affect skeletal muscle health (1, 2). This is of particular concern among older adults who are already at high risk of muscle mass and strength loss. Unlike younger adults who “bounce back” relatively easily from transient periods of inactivity, recovery in older adults is slow and may be incomplete (1, 2). As such, these periods of inactivity may have long lasting negative effects on physical function and mobility. Fortunately, simple measures can be taken to minimise the deterioration in muscle health.

Cross-sections of muscle showing the impact physical inactivity can have on muscle mass during ageing. Source: McLeod M., Breen L., Hamilton D.L., Philp A. (2016) Live strong and prosper: the importance of skeletal muscle strength for healthy ageing. Biogerontology 17(3):497-510.

Nutrition and maintaining muscle mass for older adults

What we eat can help us to maintain our muscle health while remaining at home, especially when combined with resistance exercise. Protein-rich foods combined with a balanced diet of whole grains, fruits, and vegetables can be an important part of staying healthy and maintaining mobility.

Protein power

Compared to younger adults, older adults are less efficient at using the protein they eat (found in foods like milk, yogurt, fish, eggs, meat, beans, nuts) to build new muscle (3). This means that older adults need more protein in their diets than younger ones and not eating enough protein can contribute to muscle loss. Expert groups recommend that healthy older adults should consume 1.0 – 1.2 g of protein per kilogram of body weight per day to help preserve muscle (4, 5). It is particularly important to ensure that older adults continue to consume adequate amounts of protein while isolating. Some tips include:

Prioritise protein – as physical activity levels fall during social distancing, the number of calories we burn per day decreases and appetite may also decline. Prioritizing protein-rich foods can help maintain a similar protein intake as before social distancing was introduced.
Choose high quality sources – higher quality protein sources (e.g. milk, yogurt, fish, eggs, meat, poultry) are better at stimulating muscle growth compared to lower quality protein sources (6). Getting a moderate-size serving of high quality protein (25-30 grams) at each meal can improve muscle retention.
Boost breakfast – breakfast tends to be low in protein, so breakfast foods are an opportunity to boost daily protein intake. Making porridge with milk rather than water, adding Greek yogurt to muesli or a smoothie, making an omelette or scrambled eggs, or drinking a glass of milk alongside your meal are all common ways of boosting protein at breakfast.
Pair protein with exercise – the exercise will make muscles more efficient at using the protein from the meal to build new muscle (7).
Pre-bed protein – consume a protein-rich snack (e.g. Greek yogurt, cottage cheese) before bed to boost muscle building rates overnight (8).

Calories count

Studies indicate that consuming either too few or too many calories over several weeks can worsen muscle loss during periods of inactivity (9, 10). It is normal for people to have a slightly lower appetite when they are less active than usual at home. However, if appetite drops considerably and results in weight loss, this may accelerate muscle loss.

Small, nourishing snacks frequently throughout the day to give a constant source of protein (e.g. milky drinks, yogurts, crackers and cheese, custard) and add extra calories to meals (e.g. add milk, skimmed milk powder or cream to soups and mashed potatoes, use full fat dairy products) are two ways to prevent appetite-related weight and muscle loss.

Alternatively, some people may find that, despite decreased activity levels, they are eating more than usual due to boredom or stress. In this case, eating plenty of fruit and vegetables which are low in calories and high in fibre can people stay full. Prioritising protein-rich foods as discussed above and reducing intake of high-calorie, low protein foods (e.g. biscuits, chocolate, crisps, sweets, butter) can help reduce risk of weight gain.

Physical activity to maintain muscle mass

Use it or lose it

The best way to protect muscles against the adverse effects of inactivity is to keep using them. Resistance exercise, defined as exercising muscles against an external force (e.g. weights, resistance bands, our own body weight), is by far the most potent strategy to maintain muscle mass and strength. Research has shown that incorporating resistance exercise during periods of reduced activity can attenuate or even abolish the decline in muscle mass (11, 12) and strength (12, 13). Importantly, even relatively low amounts of resistance exercise appear to be effective once performed regularly (e.g. every other day) (12). Although most older people may not have access to resistance training equipment at home, body weight exercises can be performed (e.g. sit-to-stands, wall push ups, leg extensions from a chair). It is important for people to check with their doctor to find out if they have any contra-indications to exercise or if there are any reasons to modify their workout.

Reduce sedentary time – exercise “snacks”

Engaging in physical tasks around the house each day like gardening, active chores (e.g. sweeping, hoovering) or even walking around while on the telephone can help to minimise inactivity while staying at home, thus reducing the detrimental effect on muscle.

People can also break up prolonged periods of sitting with “exercise snacks”. Exercise snacks are short bursts of exercise spread throughout the day (e.g. briskly climbing the stairs during ad breaks on TV). A recent study reported that performing brisk stair climbing (approximately 20 seconds of climbing per “snack”) three times per day, three days per week, improved fitness and leg power in sedentary people (14). Therefore, exercise snacks like these may help to reduce declines in fitness that occur during periods of inactivity.

Stay on track

Staying motivated can be difficult, especially when we are isolated at home and separated from loved ones. To maintain muscle health it is important to keep up the exercise and healthy eating for the duration of isolation. Some tips to help stay motivated include:

Set goals about when and where to do the exercise (15)
Choose activities you enjoy (16)
Monitor your exercise using diaries or apps or ask a friend or family member to monitor you (15)
Plan your protein-rich meals for the week ahead and make a shopping list
Keep a stock of protein-rich foods (e.g. tinned fish, freeze extra poultry, meat and fish)
Experiment with new protein-rich recipes to keep things interesting

To learn more about how COVID-19 is affecting the food and beverage industry, including changes in consumer preferences and purchasing behaviours, visit Kerry’s COVID-19 resource page.

Webinar – Active Ageing: Distinct Nutrition, Distinct Innovation?

Erik Bauer — Mon, 16 Dec 2019 20:14:50 +0000

Did you know older adults need much more protein than younger adults to achieve the same rate of muscle growth? Maintaining muscle mass as we age is key for staying active and independent, and is one of the main considerations for ‘healthy ageing’. This webinar reviews the state of the science on protein for ageing, and looks at other emerging scientific evidence on plant-based diets, cognition, and more to find creative ways to address needs of healthy agers through product formulation.

Read a summary of the webinar from Nutrition Insight here: Can we age healthily without animal protein? Aging population presents high-protein NPD opportunity.

Muscle Ageing – Nutrition Interventions During Adulthood

Erik Bauer — Thu, 30 Mar 2017 11:22:39 +0000

Ageing is an inevitable process affecting an increasing proportion of the world’s population due to increasing life expectancy worldwide. Delaying and/or reducing the rate of muscle ageing has been identified as a key strategy to minimise frailty and maintain independence in the elderly, with the goal of maximising quality of life during the golden years.

The Retiring Nature of Taste Perception

Erik Bauer — Fri, 10 Mar 2017 09:30:12 +0000

The taste of food changes as one gets older. Considerable differences exist between an elderly person and a younger person in regards to sensory perception and pleasantness of food flavours and taste. Salt and bitter taste acuity declines with age, but sweet and sour perceptivity does not (Methven L. et al., 2012). Olfactory acuity also declines with age. The sense of smell is more impaired by aging compared with the sense of taste. These changes affect an older individual’s food preferences and choices, appetite, dietary intake, and nutritional status.

The Impact of Taste Changes

As one ages, the body goes through changes that are triggered by both the aging process and alterations in health, nutrition, sleep and exercise that affect the body at the cellular level. These changes affect the sensory system of the body, and can impact an individual’s dietary intake. Older people slowly lose their sense of taste and smell, affecting how much they eat and the kinds of food they choose. Changes in smell and taste can affect food preferences. Food can become tasteless and unappetizing as a result of declining taste and smell perception. If food doesn’t taste appetising or smell appealing, it is likely it won’t be eaten.

Recommended changes in diet such as limiting intake of salt, sugar or fat, can also lead to lower food intake. Elderly should be encouraged to add seasonings to their food instead of relying on excessive consumption of salt and sugar to give their food flavour. Taste helps us detect spoiled food or liquids; a problem with taste perception can weaken or remove this early warning system. A distorted sense of taste can also be a serious risk factor for illnesses that require sticking to a specific diet for example loss of taste can cause one to eat too much sugar or salt to make food taste better, which can be a problem for people with such illnesses as diabetes or high blood pressure. In severe cases, loss of taste can lead to depression.

Taste and olfaction disorders should be considered a part of the aging process. Loss of taste does not happen drastically with age. Instead, it begins around middle age and continues to decline through the remainder of life. The tongue has approximately 10,000 taste buds that are responsible for differentiating sour, sweet, salty and bitter tastes. That number of taste buds begins to decrease beginning at age 40 in women and 50 in men. Sensitivity doesn’t begin to decrease until after age 60.

As one ages, and produces less saliva, dry mouth can also affect the sense of taste. Changes in the function of taste can also result from prior upper respiratory infections, head injuries, medication use and other idiopathic causes more common in the elderly, such as tooth loss and dentures. Individually, each taste bud goes through a constant cycle of birth, death, and rebirth that lasts about two weeks. A healthy tongue sloughs off and regrows these taste buds constantly. With the onset of middle age, the taste buds continue to die and be shed, however a smaller number regenerate as the years go on, contributing to fewer taste buds in the mouth, and consequently flavours begin to taste blander. Loss of taste or changes in taste are often localised to one area of the tongue and not the whole tongue.

Taste and smell are interconnected – the decline in ability to smell and differentiate smells influences taste perceptions. Sense of smell declines once we hit middle age; there is ongoing research to explore the neuroscience behind these changes. Decline in smell can be attributed to a decrease in the number of nerve fibres in the olfactory system. Even without an illness or disease, age can trigger a decrease in the effectiveness of the nerve cells. A reduced number of cells and reduction in sensitivity of those remaining cells, results in a change in the ability of the individual to interpret smell, which in turn impacts taste.

Food and beverages targeting older individuals should offer flavours that are more appealing to their taste preferences, they should utilise higher intensity aromas in certain cases and lower intensity of others, with varying textures and smaller portion sizes to accommodate the changes in taste, smell, appetite and food preferences.