Having a healthy immune system is vital for good health and there are many factors which can positively inﬂuence it. While leading a healthy lifestyle that incorporates healthy eating habits and regular physical activity can be considered as the de facto standard, many do not realise your immunity is closely linked to good digestive health as it is critical in keeping your immune system functioning optimally. However, most people tend to place very little emphasis on digestive health.
Unhealthy dietary habits and sedentary lifestyles are the main factors that contribute to poor digestive health. In addition to all these factors, a less well-known fact is that your digestive system accounts for as much as three-fourths of your body's immune system. Deep in your gut exists a large collection of microorganisms (e.g. bacteria, viruses, fungi and yeasts) collectively dubbed the gut microbiome. Just looking at the population of bacteria alone is interesting, as there are both 'good' and 'bad' bacteria. The balance between both determines the state of your digestive health.
The gut microbiome is critical for overall good health and well-being. Keeping a healthy balance of 'good' and 'bad' bacteria is essential in order to maintain your health and well-being. Research has determined that there are 'good' bacteria that reside in your gut. These helpful bacteria provide you with many beneficial functions for our body and mind.
Among some of its important functional roles are assisting with normal gut functions (e.g. helps the digestion process, regulates bowel movements, reduces symptoms of digestive disorder such as bloated, tummy discomfort, diarrhoea and constipation). Bear in mind that around 80% of your entire immune system centres on your gut. Thus, maintaining a healthy balance of good vs bad bacteria will benefit your immune system.
Associate Professor Dr Raja Affendi Raja Ali, Consultant Physician and Gastroenterologist at the Hospital Canselor Tuanku Muhriz, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM) explains, "Good bacteria helps your immune system in several ways. One method is by forming a barrier on the intestinal wall – this prevents harmful microorganisms from easily entering the mucosal barrier. The good bacteria also help the immune system by modulating its response to harmful external threats."
Various global studies
Research on good bacteria, or 'probiotics', is happening all around the world. Studies have shown promising links between probiotics and immunity.
In a European country, a 2010 study on children who attended day care revealed that daily intake of Lactobacillus helped to decrease the risk of upper respiratory tract infections1.
Subsequently, a 2011 study on healthy adults who lived in the United States of America showed positive results to their immunity after receiving an inﬂuenza vaccination followed by daily consumption of probiotics (Lactobacillus in this case). The results of the study showed promise in enhancing their immune response after receiving the vaccination compared to healthy adults who did not consume probiotics2.
More recently, in 2017 study performed in New Zealand showed how daily intake of probiotics reduced the duration and incidence of infections among elite rugby players2.
"Probiotics can help the immune system to deal with infections which are mainly spread via the mucosal membrane, such as the inﬂuenza virus. This research suggests that regular consumption of Lactobacillus can pave the way for improved immune responses," Assoc Prof Dr Raja Affendi elaborates.
Local study on probiotic benefits
Not to be left behind, Malaysia is also studying the efficacy of probiotics in the local context. The ongoing research is conducted by researchers at Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM). The research team, led by Assoc Prof Dr Raja Affendi, have so far demonstrated evidence that the Lactobacillus acidophilus and Lactobacillus paracasei strains provide noticeable improvements to digestive health and shown excellent potential to positively inﬂuence the immune system.
Thus far, they have demonstrated clear evidence that probiotics help improve digestive health. Clear improvements were noted, with:
- up to 33% reduction in intestinal transit time (ITT), which is the time it takes for food to travel from your mouth through your digestive tract and eliminated as stool.
- significant improvements in constipation symptoms among the Malaysian research subjects such as 45% of subjects spent less than 10 minutes in the toilet and 36% of the subjects need not strain so much as before.
An improved ITT is good as any the toxin build-up (due to constipation) is minimised. It also means that your digestive system is able to absorb nutrients more efficiently.
A healthy diet
Assoc Prof Dr Raja Affendi cautions against relying solely on supplements to help balance our gut microbiome. Probiotics can be found naturally in cultured milk drinks, yogurt, raw tempeh, and fermented foods (e.g. kimchi or acar).
However, in order for probiotics to ﬂourish in your gut, you should also 'feed' it with prebiotics, which can be found in certain dietary fibres such as whole grains, onions, garlic, banana, shallots, leeks, and asparagus. He also points out that while consuming probiotics is important, one should not neglect the other factors that affect digestive health.
"When it comes to your health, there is no shortcut or magic pill. Don't neglect the basics such as eating a healthy diet, exercising regularly, getting sufficient sleep and managing your stress levels. Leading a healthy lifestyle is the best thing you can do to minimise your risk of illnesses," he advises.
- 1 Hojsak I, Snovak N, Abdovic S, et al (Clinical Nutrition 29, 2010): Lactobacillus GG in the prevention of gastrointestinal and respiratory tract infections in children who attend day care centers: A randomized, double-blind, placebo-controlled trial
- 2 Davidson LE, Fiorino A, Snydman DR, et al (European Journal of Clinical Nutrition, April 2011): Lactobacillus GG as an Immune Adjuvant for Live Attenuated Influenza Vaccine in Healthy Adults: A Randomized Double Blind Placebo Controlled Trial
- 3 Haywood BA, Black KE, Baker D, et al (Journal of Sports Science & Medicine, July 2014): Probiotic supplementation reduces the duration and incidence of infections but not severity in elite rugby union players