Microbiome, Diet and Health
The gut microbiota, which encompasses the trillions of organisms in the gastrointestinal tract, is emerging as a major factor in the health of the body and susceptibility to disease. These organisms assist with digestion, protect against invading organisms and help regulate metabolism, weight, hormones, mood, behaviour and immunity (1).
While genetics, method of birth, physical environment, age, stress, and other factors all influence the gut microbiota, it turns out that diet may be the single most important driver of gut bacterial composition and function.
A recent research trial analysed the composition of participants’ gut microbiomes, their dietary habits, and cardiometabolic blood markers. Strong links were found between a person’s diet, their gut microbiome and their health. The findings suggest that diets considered to be healthy or rich in plant-based foods encourage the presence of gut microbes that are linked to a lower risk of common illnesses such as heart disease, obesity and diabetes. It appears that the microbiome has a greater association with these risks than other factors, such as genetics.
Specific Microbes, Food and Health
The findings suggest that there are microbes that are linked to eating specific foods and that these affect metabolic health. For example, it was found that having a microbiome rich in Prevotella copri and Blastocystis species was associated with maintaining a favourable blood sugar level after a meal. Other species were linked to lower post-meal levels of blood fats and markers of inflammation (1).
Microbiome and Micronutrients
Body stores of some micronutrients are significantly higher than the composition of the diet would suggest as the microbiota produce some nutrients which are then absorbed from the colon. These include B vitamins and vitamin K (2).
Artificial Sweeteners and the Microbiome
Artificial sweeteners, such as aspartame and sucralose, appear to have a negative effect on the composition of the gut microbiota. Findings suggest that the changes to the microbiota caused by the sweeteners may lead to the development of glucose intolerance, insulin resistance and weight gain (3,4).
It’s becoming clear that it may be necessary to reassess the criteria used to evaluate the safety of food additives and ingredients, taking into account their effects on the microbiome.
Implications for COVID
The researchers found microbiome-based biomarkers for obesity, cardiovascular disease and impaired glucose tolerance, which are all key risk factors for suffering from severe COVID-19. Hopefully this information can be used to help create personalized eating plans designed specifically to improve health and protect against future illness.
Professor Tim Spector, Epidemiologist from King’s College London, said “When you eat, you’re not just nourishing your body, you’re feeding the trillions of microbes that live inside your gut.” Those gut microbes then impact on many aspects of health.
The good news is that there is lots of research being done to clarify how the microbiome can be altered through dietary and lifestyle behaviours.
1. Asnicar F et al. Microbiome connections with host metabolism and habitual diet from 1,098 deeply phenotyped individuals. Nature Medicine, 2021;
2. Jackson SA et al. Current Explorations of Nutrition and the Gut Microbiome: A Comprehensive Evaluation of the Review Literature. Nutrition Reviews, 2020;
3. Sheflin AM et al.Linking dietary patterns with gut microbial composition and function, Gut Microbes, 2017, 8:2, 113-129
4. Suez J et al. Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature. 2014 Oct 9;514(7521):181-6.