The gut comprises our gastrointestinal tract and includes the esophagus, stomach, and intestines. Primarily, it digests, absorbs, and excretes nutrients and thus it is very important to maintain a healthy gut. There are many different species of microorganisms like bacteria, fungi, and viruses residing in our gut and can be ‘good’ as well as ‘bad’ which constitute our ‘gut microbiome’ or ‘gut microbiota’. A healthy gut therefore can be defined as proper growth and concentration of these “good” bacteria and keeping in check and eliminating the ‘bad’ bacteria residing in our gut. These varieties of bacteria in the gut are an important indicator of our gut health.
Gut health is directly connected to our metabolic health like digestive health, immune and mental health. Many factors, including the foods we eat, can impact the type of bacteria found in our GI tract. Our diet thus, can have short-term and long-term effects on our gut microbiome environment.
The gut microbiome aids digestion by fermentation of non-digestible substances like fibers, starches, and endogenous intestinal mucous. The fermentation process liberates Short-chain fatty acids (SCFAs) which again support the growth of healthy microbes in the gut.
Gut microbiota has a major role to play in immunity. The ‘good’ bacteria not only are helpful in digestion but also keep in check the growth of bad bacteria which in turn leads to many infections and diseases.
Another important function is maintaining good mental health. A possible explanatory mechanism is through the Gut-brain axis (GBA). The gut-brain axis is a bidirectional communication between CNS and the gut. Foster JA et al. concluded a positive correlation of microbiota in influencing anxiety and depressive-like behaviors. Dysbiosis is shown to disrupt the GBA and thus can contribute to poor mental health.
How diet can change our Gut Health?
Emily R Leeming et al. reviewed that, typically, the gut microbiota is shaped due to a variety of factors– both intrinsic and extrinsic. Intrinsic factors are genetics, immune and metabolic regulations while extrinsic being the diet, lifestyle, and medications. It was seen that extrinsic factors elicit a predominant role in the gut microbiota.
There are generally 2 types of flora residing in our gut– Transient and Resident flora.
Transient flora is the one that keeps on changing, is highly variable from person to person, and majorly depends upon the person’s diet. While the resident flora is permanent and has some key bacterial species present in all individuals and is independent of the above extrinsic factors.
Diet plays a crucial role in maintaining a healthy gut microbiome.
Parkar G.S. et al. observed a positive correlation between the composition of the diet, time, duration, and frequency of the meals with the gut microbiota. The impact of meal timing in humans on the gut and oral microbiotas was explored in a 2018 randomized crossover study by Collado et al. who found that the timing of a meal can affect the diurnal rhythms of the salivary microbial profile. Changes in the timings are shown to increase salivary taxa, generally considered pro-inflammatory; affecting body weight, cortisol rhythm, basal metabolic rate, glucose tolerance, and body temperature.
Some foods like red meat or eggs are shown to have some substances present in them which these bacterias act on, and along with the liver, make a substance called trimethylamine-N-oxide, TMAO. This formed TMAO may augment the cholesterol buildup in the blood vessels and thus, are recommended to be consumed in moderation.
How can we change our gut microbiota?
The gut microbiota can be changed by following a proper diet and lifestyle. Some of the ways are–
● Choose more plant-based plant-based foods in the diet – Studies carried out by Ercolini D et al. found that a plant-based diet appears to be beneficial for human health by promoting the development of more diverse and stable microbial systems. This could be due to the fiber content in the vegetarian diet that has lower nutrient bioavailability, found in larger food particles, intact plant cell walls, and food without thermal treatment, which means that more nutrients reach lower in the gastrointestinal system, thus enriching nutrient delivery to the gut microbiota. This helps support normal gut microbiota development and function.
● Include more prebiotics and probiotics in the food- Probiotics are the ‘live microorganisms’ present in the food that when consumed promote the symbiosis of gut microbiomes whereas prebiotics don’t contain live microorganisms but serve as the food for these microbes. Consumption of them has been shown to promote gut health.
● Cut down on sugars and sweeteners- Consumption of sugars and artificial sweeteners upgrades dysbiosis and deteriorates gut health. In a clinical trial, it was seen that the non-nutritive sweeteners were shown to disrupt the gut microbiome of healthy people.
● Reduce stress- Stress is an independent extrinsic factor in the disruption of gut health. It has been seen that it disrupts the gut-brain axis thereby disrupting the normal flora in the gut.
● Avoid unnecessary consumption of medications like antibiotics- Antibiotics change the composition of healthy gut flora as well as increase the chances of other infections. For example, a person who takes antibiotics may experience changes in their gut bacteria that make them more vulnerable to yeast infections.
● Other ways include smoking cessation, avoiding alcohol consumption, exercising regularly, and getting enough sleep which will overall contribute substantially to robust gut health.
Avanti is India’s leading food science and nutrition expert.