the connection between gut bacteria and obesity

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In recent years, obesity has taken center stage as a worldwide epidemic. The World Health Organization (WHO) reports that almost two billion adults are overweight with a body mass index (BMI) greater than or equal to 25. There are also over 650 million individuals who are classified as obese. To gain the status of obese, an individual must have a BMI higher than 30. 

Gut bacteria may cause obesity

There are many theories about the growing weight problem. Some hypothesis that it is a combination of a sedentary lifestyle and an unhealthy diet. However, recently, researchers at Lund University in Sweden have discovered a link between gut bacteria and obesity. It appears that critical amino acids that reside in the bloodstream have a connection between the gut microbiome and weight gain. 

Individual microbiota 

Within the digestive tract of each person resides a flourishing world 300 to 500 different kinds of bacteria which also contain an estimated 200 million genes. The microbiota that lives within each person is as unique as a fingerprint. A person’s microbiota is determined by that of their mothers, the environment at birth, diet, and lifestyle. The bacteria lines the digestive tract with the highest concentrations residing within the colon and large intestine. Research has revealed that the bacteria affect your immune system, mood, and metabolism. 

Gut bacteria linked to obesity, cardiovascular disease, and diabetes

Gut bacteria appears to have a direct link to obesity, cardiovascular disease, and type 2 diabetes. Studies have revealed that individuals suffering from such diseases have specific occurrences of metabolites in the bloodstream. It is also believed that essential metabolites found in the blood can be tied to obesity. 

How can gut bacteria cause obesity?

When you consume food, your gut’s job is to break it down into tiny pieces that are absorbed into the bloodstream for fuel. The rest of the food is eliminated by the body as waste. Typically, not all of the calories that you eat are used by the body, so the gut bacteria break them down. It appears that some forms of bacteria are better able to break down food into small, usable pieces that can be utilized by the body. However, if the body does not need the digested material that it absorbs, then it is harbored as fat. So, the theory that many researchers are exploring is that individuals who have a large population of certain types of bacteria have a harder time losing weight than those who do not. 

Gut bacteria responsible for obesity

Researchers have found that four different intestinal bacteria: Blautia, Dorea, and Ruminococcus in the Lachnospiraceae family, and SHA98 have all been shown to be in high concentrations in obese individuals. Further studies have also demonstrated that the gut bacteria interact and are do not function independently of each other. 

Predicting the future with gut bacteria

In an interview for Science Daily, Marju Orho-Melander, professor of genetic epidemiology at Lund University, stated, “The differences in BMI were largely explained by the differences in the levels of glutamate and BCAA. This indicates that the metabolites and gut bacteria interact, rather than being independent of each other.”  Currently, glutamate has been shown to have a strong association with obesity. BCAA can also be used to predict a patient’s risk of developing type 2 diabetes and cardiovascular disease in the future. 

Diet can modify and change the digestive tract

Yes, your gut bacteria was handed to you at birth, but it has also gone through changes based on diet and environmental factors. Research has shown that what you eat and how you live your life has a direct effect on your microbial population. A diet high in fat is difficult to digest. As a result of such dietary choices, the fat is not readily broken down by the body and instead passes through the system.. It appears that the excessive fat intake causes an increase in harmful bacteria that may have a direct link to obesity. A high saturated and trans-fat diet alters the microbiota which places a person at risk of specific health dangers such as obesity. The increase of harmful bacteria in the gut’s microbiota promotes unwanted fat storage. 

There are ways you can maintain a healthy gut. 

  • Prebiotics: Consuming prebiotics may change or alter the gut microbial population to help prevent weight gain and protect against future health problems.
  • Fiber:  The modern Western diet typically contains less fiber and vegetables than the digestive tract requires for optimum health. This means that some gut bacteria die off. A person who consumes a diverse diet that is rich in fiber has a small number of pathogenic bacteria but a large and thriving population of beneficial microbes. 
  • Mediterranean Diet: The Mediterranean diet is rich in a wide assortment of fruits, various grains, monounsaturated fat, vegetables and polyunsaturated fat. Individuals consuming such foods have a high gut population of beneficial bacteria and a low ratio of wrong types. 
  • Vegetarian Diet: A pure vegetarian diet has the same health benefits as the Mediterranean diet; a reduction in harmful bacteria but an increase in the good varieties

Scientists have only started to discover the apparent link between gut bacteria and obesity. However, with diet modification, the microbiota within an individual can be altered to promote weight loss and a healthier long-term outlook. 

 

references: 

Lever, E., Scott, S. M., Emery, P. W., & Whelan, K. (2015). The effect of prunes on stool output, whole gut transit time and gastrointestinal symptoms: a randomised controlled trial. Proceedings of the Nutrition Society74(OCE1).

Rajoka, M. S. R., Shi, J., Mehwish, H. M., Zhu, J., Li, Q., Shao, D., ... & Yang, H. (2017). Interaction between diet composition and gut microbiota and its impact on gastrointestinal tract health. Food Science and Human Wellness.

Al-Assal, K., Martinez, A. C., Torrinhas, R. S., Cardinelli, C., & Waitzberg, D. (2018). Gut microbiota and obesity. Clinical Nutrition Experimental.