A strong immune system starts in the gut

Your digestive system accounts for the majority of your body's immune system. Studies show just how closely linked your gut are with immunity as it accounts for about three-fourths of your immune system. In fact, your gut is the home to a large population of gut microbiota which includes about a thousand different types of bacteria that are both 'good' and 'bad'. Keeping a healthy balance of 'good' and 'bad' bacteria is essential in order to maintain your health and well-being.

A Balanced Gut Microbiota for Health and Immunity

Gut microbiota refers to the collection of microorganisms that reside within your gut. Many studies have shown that the diversity and abundance of gut microbiota varies from individual to individual. Hence, a healthy human gut is dependent upon a healthy balance of 'good' bacteria (which provides you with positive health benefits) and 'bad' bacteria (which may cause inflammation and diseases).

A balanced gut microbiota helps to promote normal gut functions such as maintaining proper digestion, regular bowel movements and normal stool, as well as reducing symptoms of digestive disorders, e.g. bloating, constipation and diarrhoea.

Apart from its importance to gastrointestinal functions, a healthy balance of good bacteria and bad bacteria in the gut also provides the highest benefits to the immune system. This is because around 80% of the entire immune system is located in your gut. Part of the reason why good bacteria provides positive effects to the immune system is because they form a barrier on the intestinal wall, which prevents harmful microorganisms from being absorbed. Lastly, they also help to modulate the immune system, thus improving how it responds to external threats.

Consequences of Imbalanced Gut Microbiota

Imbalanced gut microbiota (or dysbiosis) occurs when the bad bacteria in your gut outnumbers the good bacteria and this may upset your overall gut health. The common signs and symptoms of dysbiosis include bloating, constipation, diarrhoea and abdominal discomfort.

An imbalanced gut microbiota could also lead to intestinal inflammation that might damage the gut lining, hence affecting normal gut and immune function as well as your overall health. If left untreated, dysbiosis can cause chronic digestive disorders such as Irritable Bowel Syndrome (IBS), leaky gut syndrome, celiac disease, and colon or rectum cancer.

Healthy Dietary Habits Promote Balanced Gut Microbiota

It is crucial to have a healthy balance of gut microbiota for overall well-being. You can help your body achieve an ideal balance by simply practising healthy eating, as dietary factors play a major role in maintaining a healthy gut.

Start by practising a balanced, moderate and varied diet every day and reducing the intake of foods high in sugar and fats. Consume probiotic-rich foods such as fermented milk products (e.g. cultured milk drinks and yoghurt).

Probiotics are live microorganisms which when consumed in adequate amounts has been shown to provide health benefits to the human body. Also known as beneficial or friendly bacteria, they help to replenish the 'good' bacteria in your body, thus promoting a healthy gut microbiota balance. For cultured milk containing probiotics, you should make sure the products are labelled with:

1. The total number of bacteria contained in the product
2. The genus, species and strain of probiotic used
3. Words containing "live" or "active" probiotic cultures
4. At least 106 colony-forming units (CFU) per ml or per gram of probiotic culture
5. Directions for storage

There are also various traditional fermented foods which may also contain beneficial bacteria. These foods include homemade yoghurt (tairu), fermented soy products (e.g. tempeh), and fermented vegetables (e.g. kimchi and sauerkraut).

Apart from that, you should also eat more high-fibre foods like whole grains, legumes, fruits and vegetables. Dietary fibres are non-digestible carbohydrates which can help to regulate bowel movement, thereby keeping the digestive system healthy. Some of these fibres may serve as prebiotics that help to feed the 'good' bacteria in the gut, thereby increasing the population of good bacteria. Examples of prebiotics in foods are bananas, garlic, onions, shallots, leeks, and asparagus. Besides that, other food ingredients that also serve as prebiotics are fructo-oligosaccharides (FOS), inulin and galacto-oligosaccharides (GOS) which may be added in some food products.

Healthy lifestyle improves digestive health

In order to improve your digestive health and boost your immune system, you should also look at the basic tenets of good health, namely ensuring that you do the following on a daily basis:

• get at least 30 minutes worth of exercise
• drink at least eight glasses of plain water, or more on hot days and if you play sports or exercise vigorously
• get eight hours of quality sleep
• manage stress
• if you are a smoker, quit smoking