Microbiome and Health

The microbiome (beneficial flora) of the gut continues to receive much attention for its role in many aspects of our health and wellbeing.

probiotics3The microbiome is the term given to the vast network of around 100 trillion microorganisms that live in our gut, mouth, skin and elsewhere in our bodies. These communities of beneficial bacteria have numerous important functions relevant to supporting life. They are needed for many aspects of day to day functions in the body. They help to digest food, to boost immune function and prevent other disease-causing bacteria from invading the body as well as helping in the synthesis of essential nutrients and vitamins.

(Click here to see a visual display of our amazing microbiome).

The effects on digestive function have an obvious link to the gut microbiome. It stands to reason that the gut itself, being the home of so much bacteria, will be directly impacted on by the activities and levels of good or bad bacteria found there.  Both irritable bowel syndrome and autoimmune bowel diseases, such as Crohn’s disease and ulcerative colitis, have been shown to reflect the composition of gut flora. But there are many other body systems that will be impacted on by our microbiome.

Some of the latest research is now looking at gut bacteria for its role in obesity, insulin resistance and diabetes, some of our major modern epidemics. Several controlled trials showed the benefit of prebiotics (foods for bacteria to use) and probiotics (healthy bacteria species) on insulin sensitivity, inflammation and glucose tolerance all of which are involved with diabetes and obesity.

baby antibioticsFurthermore, new research has found that use of antibiotics in early infancy can alter important gut bacteria with long term consequences. One study found children who had antibiotics before six months of age were more likely to be overweight as seven-year-olds.  Even though sometimes the gut flora returned to ‘normal’ some time after stopping the antibiotics, there were still long term permanent consequences.

twinsStudies into twins where one twin is lean and the other is obese, has shown very different levels of gut bacteria. Interestingly, when they inocluated mice with the different bacteria from each twin, the mice developed either obesity or stayed lean. However, it was dependent on the mice also having a healthy diet. A high fat, processed diet in the obese mice inoculated with the lean twin’s bacteria did not colonise the gut, whereas mice consuming a diet rich in fruit & vegetables and low in processed fats were able to colonise the lean bacteria and then lose weight.

Thus for children, we need to focus on a healthy lifestyle, including promoting vaginal births, breastfeeding and avoiding antibiotic use (where possible) as well as a whole food diet to ensure a friendly gut microbiota which will help prevent future disorders like obesity and diabetes.

ghrelinleptinfoodintake_300Other studies in adults implicating antibiotics as a player in obesity and diabetes, found that after antibiotic use there was a disruption in the hunger hormones ghrelin and leptin. This lead to a change in feelings of satiety (fullness after a meal) with a tendency towards overeating and the inability to burn fat stores.

The connection between the gut and the brain is another important aspect that has been researched for a number of years. The gut has receptors to all our neurotransmitters (hormones connected to mood, behaviour, cognition and sleep) and research now shows that there are more of these located in the gut than the brain. So the state of our gut has a very big capacity to affect our mood and behaviour. This is why the holistic approach to behavioural disorders in children (and mental health issues in adults) always factors in food intolerance and gut health as key treatment considerations. Studies have shown that people responded with an increased mood while taking prebiotics that promote healthy gut bacteria.

What we eat has a major impact on the types of flora that we have. Microbiologists have known for some time that different diets create different gut flora populations.  In fact, new research has found that the changes in gut bacteria from diet can happen incredibly fast in the human gut – within three or four days when there is a big shift in what you eat. The researchers were surprised at the speed at which the bacteria populations could change. What they thought might take days, weeks or years began to happen within hours of dietary change.

leek and garlicSugars are know to feed pathogenic yeast and fungi such as candida and processed refined foods tend to deplete beneficial bacteria. This type of diet, which is so common today, creates the perfect environment for harmful bacteria to thrive and healthy bacteria to be destroyed.

In contrast, foods that promote good bacteria tend to be high in fibre and complex carbohydrates such as vegetables, seeds, nuts and legumes. Vegetables such as garlic and leek as well as the herbs Dandelion and Chicory are very good sources of inulin which is a well known beneficial prebiotic. (Stay tuned for my next article which will have more detailed information about using specific foods in our diet to have a beneficial impact on our gut flora!)

This fascinating area of research continues to evolve and I am sure we will increasingly understand the vast and important role of our microbiome on many aspects of health, including our gene expression,  over coming years.