Nutrition

In addition to regular activity, a healthy balanced diet that includes fresh fruit and vegetables supports the immune system, reducing the risk of communicable and non-communicable diseases. In contrast, a poor diet compromises immunity and leads us susceptible to infections.

Specific food and dietary patterns also influence the gut microbiota, which has been implicated in the development and progression of several health conditions. Modulating the microbiota to improve health is a rapidly growing science.

Gut microbes in the lower intestine, such as Bifidobacteria and Lactobacteria, break down complex carbohydrates from dietary fibre. This process produces short-chain fatty acids that play an important role in muscle function and the prevention of certain cancers and bowel disorders. For example, colon cancer seems to stem from an interaction among the microbiome, the immune system and epithelial cells that line the colon.

In contrast, certain food additives such as emulsifiers in processed foods have been shown to reduce microbial diversity, with an increase in inflammation-promoting bacteria. Restricted diets such as low carbohydrate diets are fashionable and, in the short term, can have health benefits. However, cutting out this food group in the longer term can reduce the diversity of the gut microbiome.
Essential nutrients for beneficial gut microbes are found in plant-based carbohydrates present in fruits, vegetables, nuts and whole grains. Some research suggests that longer term low carbohydrate diets increase the risk of cancers, stroke and heart disease.

While further studies are necessary to investigate the benefits of fermented foods, they have been linked to positive health benefits since the early 1900s. Data demonstrates that fermented foods can be more easily digested, providing nutrients to promote or inhibit microorganisms in the microbiota, the fermented bacteria themselves resting with the resident gut bacteria.

Nutritional factors have also been implicated in the aetiology of autistic spectrum disorders. Abnormalities in carbohydrate digestion and absorption could explain some gastrointestinal problems seen in this population. Improving gut health has seen improvements in some patients.

Physical activity also increases the diversity of bacteria in your gut and can increase the metabolism of short-chain fatty acids and anti-inflammatory metabolites. So, maintaining a certain level of activity, even low-impact exercise, can prevent dysbiosis, improve gut barrier functions and decrease the risk of illness.

• Valdes AM, Walter J, Segal E, Spector TD. Role of the gut microbiota in nutrition and health. BMJ. 2018 Jun 13;361:k2179. doi: 10.1136/bmj.k2179. PMID: 29899036