Why is intestinal bacteria beneficial

Researchers have found that even though the composition varies between individuals, different compositions can have similar functions e. It has therefore been suggested that the function of the gut microbiota, rather than the composition, is more important for health.

The microorganisms present in the gut play a crucial role in digestive health, but also influence the immune system. Immune tissues in the gastrointestinal tract constitute the largest and most complex fraction of the human immune system. The intestinal mucosa is a large surface lining the intestine and is exposed to pathogenic disease-causing and non-pathogenic environmental antigens substances that trigger the immune system to produce antibodies.

In the gut lumen, the microorganisms play a critical role in the development of a robust and balanced immune system. In recent years researchers have established a link between the gut microbiota and body weight. Although much of the research is still in its early stages, studies have revealed that people with obesity tend to have a somewhat different composition of gut bacteria compared to lean individuals.

Much of the evidence on the association between the gut flora and risk of obesity so far comes from animal studies. Findings from animal studies indicate that the microbiota of a person with obesity i. This area of research is fairly new and more studies, in particular in humans, are needed to understand how and to what extent the composition of microorganisms in the gut influences various metabolic functions in the body. Probiotics are defined as live microorganisms, which, when administered in adequate amounts, may confer a health benefit.

Numerous types of probiotics have been studied. There is some evidence that certain probiotics are effective in improving symptoms of irritable bowel syndrome, ulcerative colitis a form of inflammatory bowel disease , and infectious disease, as well as reducing the risk of developing eczema and other allergic conditions. Also healthy individuals may benefit from taking probiotics — there is some evidence suggesting that probiotics can reduce the risk of infectious diseases, including upper respiratory tract infections, in healthy populations.

This means that if an effect of one probiotic strain is found, no conclusions about the possible effects of other probiotic strains can be made. The European Food Safety Authority, which provides scientific advice to the European Commission, has so far rejected any health claims for use on food products that suggest that healthy individuals benefit from taking probiotics.

More research is underway, using newer technologies and specific biomarkers that may help understand whether or how individuals may benefit from the use of probiotics. It is only in the past 10 years that it has become possible for microbial ecologists to contemplate a description of the microbiota in any habitat. Now, new technologies such as genetic sequencing machines can rapidly describe microbial communities in terms of genetic markers, bypassing the need to culture.

A recent study, for instance, used computational analysis to look at how many and what kinds of microbes are in the gut and found that bacterial species are even more diverse than previously thought. As soon as the amniotic sac is broken, we are exposed to bacteria. If we are born via a vaginal delivery, we begin by getting a dose of microbes from the birth canal, but if born by caesarean section our first dose is from the skin of our carers. Differences due to this initial exposure can be seen in the microbial community of babies for several weeks at least, although the significance of this is hotly debated.

As we grow, and begin to put all kinds of things into our mouths not just a variety of foods, but all those other goodies that toddlers like to taste test we introduce new microbes into our gut. Sometime between a period of six months and three years, a stable microbiome composition is attained.

This happens in association with the adoption of an adult-like diet and the completion of immune development.

They remain stable for periods of a year or more in the absence of certain external factors, discussed below in terms of the types of species present, though varying in the abundance of the different species.

As we move through life, our microbiota is affected by disease states; changes in age, diet, and geographical location; intake of food supplements and drugs, including antibiotics; and other environmental influences. There are also differences between populations. Some, such as Salmonella , are harmful to us. But many are harmless, and others, it seems, are positively helpful.

Helicobacter pylori , for example, can trigger the formation of gastrointestinal ulcers but has recently been found to have benefits for appetite regulation. If we take a step back and consider our microbiome as a system, we can see that microbes and people live in a mutually beneficial symbiotic relationship.

We feed them goodies and, in return, they do a whole heap of things for us, like:. As it encounters a diversity of microbes in the gut, the immune system learns which pathogenic bacteria to attack and which beneficial bacteria to leave alone. The development of defined arms of the immune system thus goes hand in hand with the acquisition of a complex microbiota. Numerous potential explanations have been put forward, including extensive use of antibiotics, which can decimate microbe populations; changes in what we eat especially the trend towards more highly processed foods ; and more hygienic living conditions, which have led to the decline of some potentially useful microbes in the gut.

Whatever the causes are, there is no doubt that we have changed our association with microbes, and the consequences are turning out to be numerous. People whose intestines have smaller and less diverse bacterial populations appear to be more prone to obesity.

Comparing lean and overweight people in a study of twins, researchers found that the gut community in lean people was very diverse. They had a wider variety of Bacteroidetes, for instance, which specialise in breaking down bulky plant starches and fibres into shorter molecules that the body can use as a source of energy.

In another experiment, by researchers at Washington University in St Louis, Missouri, germ-free mice were populated with bacteria from lean and obese women. Even though they were fed the same diet and in the same amounts, those with the bacteria from the obese women grew fatter also associated with a less diverse gut microbiota. Next, the lean mice were placed in the same living quarters as the obese mice. Consequently, the obese mice became leaner. The absence of certain microbes may also mean we may not be able to effectively regulate our appetites, potentially leading to obesity.

Although it was once common in our digestive tracts, the prevalence of H. Some studies have revealed a connection between gut microbiota and the brain. More specifically, gut microbes may have a role to play in anxiety and depression. However, new evidence suggests that babies may come in contact with some microbes while inside the womb 4 , 5 , 6. As you grow, your gut microbiome begins to diversify, meaning it starts to contain many different types of microbial species.

Higher microbiome diversity is considered good for your health 7. Therefore, there are a number of different ways in which the gut microbiome can affect key bodily functions and influence your health. The gut microbiome affects the body from birth and throughout life by controlling the digestion of food, immune system, central nervous system and other bodily processes.

There are thousands of different types of bacteria in your intestines, most of which benefit your health. An imbalance of healthy and unhealthy microbes is sometimes called gut dysbiosis, and it may contribute to weight gain Several well-known studies have shown that the gut microbiome differed completely between identical twins, one of whom was obese and one of whom was healthy.

This demonstrated that differences in the microbiome were not genetic 22 , Interestingly, in one study, when the microbiome from the obese twin was transferred to mice, they gained more weight those that had received the microbiome of the lean twin, despite both groups eating the same diet Fortunately, probiotics are good for a healthy microbiome and can help with weight loss.

Nevertheless, studies suggest that the effects of probiotics on weight loss are probably quite small, with people losing less than 2. Gut dysbiosis may lead to weight gain, but probiotics can potentially restore gut health and help reduce weight.

The microbiome can also affect gut health and may play a role in intestinal diseases like irritable bowel syndrome IBS and inflammatory bowel disease IBD 25 , 26 , The bloating, cramps and abdominal pain that people with IBS experience may be due to gut dysbiosis. This is because the microbes produce a lot of gas and other chemicals, which contribute to the symptoms of intestinal discomfort Certain Bifidobacteria and Lactobacilli , which are found in probiotics and yogurt, can help seal gaps between intestinal cells and prevent leaky gut syndrome.

These species can also prevent disease-causing bacteria from sticking to the intestinal wall 29 , In fact, taking certain probiotics that contain Bifidobacteria and Lactobacilli can reduce symptoms of IBS A healthy gut microbiome controls gut health by communicating with the intestinal cells, digesting certain foods and preventing disease-causing bacteria from sticking to the intestinal walls. Fill Up on Fiber. Pick Prebiotic-Rich Foods. Try Probiotic Foods. Avoid Animal Products. Limit Fats.

Avoid Unnecessary Antibiotics. Practice a Healthy Lifestyle. Join the Day Vegan Kickstart! Try these plant-based recipes Recipe Tempeh Sloppy Joes. Recipe Broccoli Burritos. Recipe Facon Bacon.