Two recent publications in the American Journal of Clinical Nutrition continue to provide support for the role of whole grains in a health-promoting diet. Continuing to promote whole grain intake and incorporate whole grains into food products remains key to improving health.
The articles come from a controlled-feeding study which compared the effects of a whole grain (WG) diet to a refined grain (RG) diet. Study participants included 49 men and 32 women between the ages of 40-65 years old. In a controlled-feeding study, the diets of participants are provided by researchers and strictly controlled – the difference between the groups was the substitution of whole grains for refined grains in one of the two groups.
The whole grain group consumed an average of 207 grams per day of whole grains and 40 grams of dietary fiber per day compared to 0 grams of whole grains and 21 grams of dietary fiber consumed by the refined grains group. For this study, diets were adjusted to prevent weight loss.
Energy Balance Benefits
Those consuming whole grains in the study burned nearly 100 more calories per day than those consuming refined grains, suggesting whole grains may be able to help us maintain a healthy weight. These whole-grain effects on energy balance come through a combination of increasing the resting metabolic rate of participants and preventing energy absorption from food, likely via the fiber in whole grains.
Grains for Gut Health
Whole grains promoted gut health in study participants, as well. Those consuming whole grains had increases in stool weight and frequency, which are both measures of gut health. The whole grain group also showed an increase in Lachnospira bacteria in the gut, which are short-chain fatty acid producing bacteria, and a decrease in the pro-inflammatory Enterobacteriaceae bacteria, suggesting whole grains may foster a healthy gut microbiome in humans.
Boosting the Innate Immune Response
Finally, those consuming whole grains had an improved acute innate immune response, meaning it’s possible that whole grains improved the body’s ability to ward off infection. The GI tract is strongly linked to our immune system since that is where we primarily come into contact with “external threats”.