While some bacteria are associated with disease, others are actually very important for strengthening of our immune system, proper functioning of the body organs including heart, maintenance of body weight and many other aspects of health. Trillions of these microbes exist in our body system particularly in the intestines and skin. Most of the microbes are associated in the large intestine in the form of a pocket called the cecum, and they are referred to as the gut microbiome. Although many different types of microbes are present in our body, however most of the studies have been carried on bacterial composition of the digestive gut system. In fact, there are several reports that the human body contains more number of bacterial cells than the actual human cell counts. It has been estimated that roughly 40 trillion bacterial cells are present in our body whereas human cells counts are around 30 trillion. Scientists all over the world have reported about 1,000 species of bacteria in the human gut microbiome, and each of them plays a different role in the body. Most of them are extremely important for maintaining our body health, while few species may be harmful in creating some serious diseases. Altogether, these microbes may weigh as much as 2–5 pounds (1–2 kg), which is roughly the weight of our brain.
Gut microbiome composition: Intestinal microbiome community (Source: internet web) Human microbiome consists of microorganisms like bacteria, archea, fungi, protozoans, and viruses. Among all microbiome micro-organisms, bacteria are the most predominant and the presence of bacterial population has been estimated between 75 to 200 trillion in a single person. The first bacterium that was noticed in the intestinal region was Escherichia coli in healthy children and in the children suffering from diarrheal disease. Other bacterial species observed were Veillonella parvula in the digestive tract and Bifidobacteria in the intestinal fluid. Later number of micro-organisms has been identified in the human gut system after the discovery of the molecular tools for DNA analysis. It has been estimated that human microbiota consists of more than 1000 different species of microorganisms. Further it is reported that human gut microbiome contains more than 160 species of bacteria. Besides healthy bacteria, there are number of unhealthy/pathogenic bacteria like Staphylococcus, Streptococcus, Enterococcus, Klebsiella, Enterobacter and Neisseria causing various types of intestinal disorders. Clostridium difficile a pathogenic bacterium most commonly found in the human gut microbiome causes severe recurrent diarrhea. The bacterial species like Prevotella and Firmicutes and their abundant presence in the gut system have been correlated with obesity.
Microbiome benefits: Microbiome in human body is associated since our birth time onwards and play very important role to carry out various physiological functions. There are also reports that once the baby is born in mother's womb the baby is exposed to the microbes through mother's placental cord. However, new evidence suggests that babies may come in contact with some microbes while inside the womb. As the baby grows the gut microbiome of the baby begins to diversify indicating that different types of microbial species start accumulating and it is assumed that more the diversification is good for the health. Later depending on the food we eat affects the composition, quality and diversity of the gut microbiome. Dietary food habits always influence the diversity of the gut microbiome which in turns affects the body functions. For example Bifidobacteria first begins to grow in the new born babies' intestine because they very much essential for the digestion of healthy sugars in the breast milk and these sugars are important for growth of the babies. There are certain bacteria which digest the fiber, producing short chain fatty acids and these fatty acids are most essential for the maintenance of gut health. Fiber may also help to prevent weight gain, diabetes, heart disease and the risk of cancer etc. There are several reports indicating that the gut microbiome help in improving the immune system. By communicating with immune cells, the gut microbiome can control our body by developing resistance to the infectious bacteria. In recent years several researchers have found out that the gut microbiome also plays important role in controlling the neurodegenerative disorders like Alzheimer's disease and Parkinson disorder. Therefore, there are a number of different ways in which the gut microbiome can affect key bodily functions and influence our health. There are several other benefits and few of them are summarized below.
Gut microbiome and body weight
Several studies on the composition of microbiome present in our intestinal portion have shown that there are thousands types of different bacteria involved with our body system. The composition analysis indicates the presence of both good and unhealthy bacteria. When there is a dominance of unhealthy microbes in the gut system which is also called gut dysbiosis then there is a possibility of increase in our body weight. Several confirmed 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 diversity is not genetic related. Interestingly, in one study, when the microbiome from the obese twin was transferred to mice, they gained more weight than those that had received the microbiome of the lean twin, despite both groups eating the same diet. These studies indicated that microbiome dysbiosis may play a role in weight gain.
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January - February 2020