Posted on by Britt Merrylees

By Dr Malcolm Ball

While the digestive process may not be regular dinnertime conversation, it is probably the most important part of your life. Let’s discuss the organs that help you digest your food, and in a real sense determine whether we are healthy or not.

The liver, pancreas, stomach and intestines work together to digest food, absorb nutrients and expel harmful waste – each one playing a unique role and complementing one another. Digestion is so interconnected that an issue with one organ will often produce a chain reaction throughout the system. So maintaining a healthy digestive system is vital to overall health.

The digestive process exists to provide our bodies with everything that we need to live apart from oxygen, this includes provide us with micronutrients to make enzymes function, amino acids to repair old cells and create new ones and fats and carbohydrates to convert to glucose for energy. There is a tendency to think of the pancreas and insulin when managing blood glucose levels however the truth is that all these organs, and the gut microflora all play an active roll in how blood glucose is managed. When any one of these integrated elements can’t do its job effectively, the whole system is affected. While the liver controls how glucose is released and to what organs, the pancreas regulates these glucose levels with insulin.

As our understanding of digestion expands we are beginning to realise that perhaps one of the key roles in human digestion falls to the gut microbial population (also called the microbiome) . While the gut microbiome may not be considered an ‘organ’ in the classic sense, the large microbe population living in our intestines is absolutely vital to our digestive health, as well as affecting inflammation and a range of other conditions. Think of the gut microbiome as a a sound board in a recording studio with each of the individual microbial populations as one of the dials; if the panel is balanced then everything is in harmony, but if one or more of the populations is too high or low then discord (poor health) results. Our microbiomes are also unique to each individual, with only one third consistent in human biology and the other two thirds developing over time, acquired and evolving by what we eat as we age(1). Essentially, the bacteria that make up the gut microbiome aid our bodies in digesting whatever the stomach and small intestine have not, as well as providing essential amino acids, vitamins and other micronutrients. The microbiome is also one of the body’s major defences against harmful pathogens.

Caring for the gut microbiome is as simple (or as complicated) as caring for yourself – the food you are putting into your body. Good nutrition works for both you and your microbial populations. Unprocessed foods that are high in vitamins, minerals and nutrients as well as dietary fibre and a good balance of protein, fats, and carbohydrates. Highly processed foods that are high in simple sugars and fats (typical in the modern diet) have been shown to have a negative impact on microbiome health, and consequently our own – including such problems as inflammation, poor blood glucose control and even an increase in serious chronic disease (2, 3). Conversely foods that are high in dietary fibre, low in processed sugars and have minimal processing have been shown to improve gut microflora and improve metabolic conditions (4). Foods that are specifically known to improve microbial health are known as prebiotic and act as ‘food’ for the good bacteria(5), alternatively you can help your microflora along with a “probiotic” that contains populations of good bacteria that can help overtake the bad living in the intestines (6). This helps microbiota function while initiating bacterial growth. Research has shown that that regular consumption of probiotic and prebiotics help maintain microbial balance and help with insulin sensitivity, inflammatory markers, postprandial incretins and glucose tolerance (7).

Why is microbial balance so important? When you are not ingesting enough probiotic and prebiotics, the bacterial growth becomes inconsistent and the gut microbiome is unable to work as effectively. This causes an increase in certain bacteria and a loss of others. This loss of balance results in dysbiosis, where inflammation increases and metabolic function starts to become impaired. Research suggests that people who suffer from diseases like Type 2 Diabetes have shown similar inconsistencies in their microbial levels – higher counts of certain bacteria and lower counts of others(8). Other autoimmune diseases and even obesity have been associated with differentiating levels of bacteria caused by an imbalance in the gut microbiome(7).

Overall, by looking after our digestion we can impact not only general wellbeing but also alleviate many metabolic conditions and even reduce the likelihood or impact of disease.


Graf D, Di Cagno R, Fak F, Flint HJ, Nyman M, Saarela M, et al. Contribution of diet to the composition of the human gut microbiota. Microb Ecol Health Dis. 2015;26:26164.

Myles IA. Fast food fever: reviewing the impacts of the Western diet on immunity. Nutr J. 2014;13:61.

Manzel A, Muller DN, Hafler DA, Erdman SE, Linker RA, Kleinewietfeld M. Role of “Western diet” in inflammatory autoimmune diseases. Curr Allergy Asthma Rep. 2014;14(1):404.

Birt DF, Phillips GJ. Diet, genes, and microbes: complexities of colon cancer prevention. Toxicol Pathol. 2014;42(1):182-8

Bindels LB, Delzenne NM, Cani PD, Walter J. Towards a more comprehensive concept for prebiotics. Nature reviews Gastroenterology & hepatology. 2015.

Poutahidis T, Kleinewietfeld M, Smillie C, Levkovich T, Perrotta A, Bhela S, et al. Microbial reprogramming inhibits Western diet-associated obesity. PloS one. 2013;8(7):e68596.

Hansen TH, Gobel RJ, Hansen T, Pedersen O. The gut microbiome in cardio-metabolic health. Genome Med. 2015;7(1):33.

Allin KH, Nielsen T, Pedersen O. MECHANISMS IN ENDOCRINOLOGY: Gut microbiota in patients with type 2 diabetes mellitus. Eur J Endocrinol. 2015;172(4):R167-R77.