Our body is not formed just over thirty billion cells and tissues responsible for such important organs such as skin, heart, lung or liver. In the digestive system they hide thousands of bacteria that help us absorb nutrients from food and have an important effect on our health. The microbes mainly found in the intestine have been called intestinal microbiota.

We might think that the microbiome, ie, the set of bacteria that live with us, has an important role in our health. However, in recent years various studies have identified that these “invisible bugs” could play a role in diseases such as cancer, HIV infection or autism.

A recent study published last week in the journal Science offered most detailed and extensive microbiome research to date. Their findings provide an unprecedented look over the set of microorganisms that coexist in our body, also determining factors that can alter its composition.

The results come from initiatives such as the Belgian Flemish Gut Flora Project and LifeLines-Deep, plus analysis of several global databases. In total, researchers have been able to study the microbiome of more than 4,000 people. The study identified fourteen types of microbes found in the gut of more than 95% of the volunteers, in addition to describing 664 different species of microorganisms in total.

Among the factors that affect our digestive system microbiome, scientists highlight the role of drugs.  Intake of medicines such as antibiotics, laxatives, female hormones, antidepressants or antihistamines alters the composition of the intestinal microbiota, according to the paper published by the team of G.  Falony .

Meanwhile, research group of Alexandra Zhernakova determined some of the parameters that directly affect the diversity of bacteria that inhabit our digestive system. According to their findings, a diet Western-style, with a greater amount of calories, snacks or milk with lots of fat, it is associated with less diversity in the microbiota and a higher amount of carbohydrates.

Consumption of sweetened soft drinks also has negative effects on gut microorganisms. By contrast, coffee, tea or red wine was associated with a greater diversity in the microbiome. Even episodes like a heart attack also affect these microbes, as having suffered a heart attack is associated with a lower abundance of bacteria Eubacterium eligens.

A third study, led by the team of Simone Li, sheds light on some of the mysteries about the microorganisms that remain after performing fecal transplants. Such interventions, particularly effective in the treatment of Clostridium difficile infection is one of the great promises in microbiome research.  Their results have identified what kind of microbes are optimal in fecal transplants, recognizing that can persist for up to three months in the intestine of the receptor. But is not the only biomedical application of these microbes. The work published by the group of Eric Pamer published in Science also explores the role they can play these “good microorganisms” in the fight against antibiotic resistance.

Understanding the composition of the microbiome and the factors influencing it is essential to take care of our health. According to another study, also published in Science, our own genetics also could have some impact on the microbial diversity of the organism. This type of microorganisms, particularly during childhood, can affect the immune system, determining the onset of disease many years later.

It is therefore essential to monitor the type of microbes that live together with our cells. One measure, conducted by the team of Martin J. Blaser, treatments could be directed against specific pathogens and abandon the broad – spectrum antibiotics, which may have very negative consequences for the whole of our microbiome. All results show the role this type of bacteria in health and the growing importance of “invisible bugs” that live in the body.