Gut bacteria

It’s not always a pleasant thought, but there are whole communities of bugs going about their daily business in your body. In fact, there’s somewhere in the vicinity of 100 trillion microorganisms within the gastro-intestinal tract of the average human, and scientists are still learning how they work. There is growing evidence that imbalances in what researchers call ‘gut microbial populations’ may be associated with all kinds of diseases, particularly bowel and digestive disorders, not to mention our brain function and energy levels.

CSIRO researchers conducted a review of the available information on gut ‘microbiata’ to encourage further research in this field. The more we learn about the intricate workings of our gut bacteria, the closer we get to figuring out exactly what, why and how much we should be eating for optimum health.

How microorganisms work in our guts
Amongst their many day jobs, gut microbes are responsible for the fermentation process that turns our food from a tasty snack into a combination of nutrients and waste products. The different bacteria play specific roles – like drawing the vitamins and minerals out of grain products, for example, or creating the enzymes that break down carbohydrates.

The trouble is that, like any community, these bacteria are also competing with each other for the specific living conditions that help them thrive. When these conditions are out of whack, the imbalance can cause problems in our bodies, ranging from bloating to a poor immune system to serious illness. Researchers are trying to determine the roles of genetics, environment, diet and lifestyle on keeping these microbe communities harmonious and, in turn, keeping our bodies healthy.

Food, lifestyle and healthy gut bacteria
What scientists already know is that microbes colonise the human gut shortly after birth and their patterns begin to change as soon as infants start eating solids. This suggests a direct relationship between diet and a healthy gut, but the jury is still out on exactly which nutrients matter most.

These shifts in microbiata continue to happen as we age; partly to meet the body’s changing needs for vitamins and minerals, and partly due to the influence of a lifetime of new foods. Early research also shows that lifestyle factors, such as pollution, lack of exercise, stress and smoking can affect the gut bacteria populations too. It is even thought that cooking practices might have an influence on good gut bacteria – so, not just what we eat, but how we eat it. We could be eating the ‘right’ foods, but in all the ‘wrong’ ways for perfect health.

Poor gut balance seems to peak at certain times of our lives, being prevalent in the elderly, for example. Research continues into whether this is to do with the ageing body, or the potentially reduced or simplified diet of an elderly person. Similarly, research shows that obese people have different gut microbiata patterns to champion athletes – but is this due to diet, exercise or pure genetics? Research in this area may be a significant step towards understanding why some people find it easier to lose weight than others, or why some approaches to diet work differently in different people.

Each individual has a unique combination of microbiata – so what works for one person may not work for all. Yet, we see tonics for our gut health advertised all the time, like the Lactobacillus and Bifidus families in yoghurt. These have been shown to have a short term positive influence, but these are only the widely available options, not necessarily the best ones for everyone. Early studies show that other substances, like a derivative of cocoa, might be much better than yoghurt at combating gut problems, but much more research is needed. Don’t reach for the chocolate bars yet!

There are still many gaps in the scientific knowledge about the relationship between diet, lifestyle, microbes and our health. We know that a diet rich in fruit and vegetables is ‘good for us’ at any age, but the ongoing examination of microbiata gets us closer to understanding exactly why that is. We don’t completely understand the role of microbes in helping our bodies to function to their potential. With further research, it may be possible to develop diets from infancy that lead to optimal microbial population health, leading to better health outcomes across the population.

Michael A. Conlon and Anthony R. Bird. (2015) The impact of diet and lifestyle on gut microbiata and human health. Nutrients, 7, 17-44.