The relationship between obesity and the gut microbiome
Chronic diseases are rapidly increasing worldwide, and obesity, which refers to severe overweight, is considered one of the main culprits (1). Although there are a variety of methods that attempt to prevent the ever-increasing weight gain, obesity remains a widespread problem. Thus, there is an urgent need to develop new solutions. Obesity-related diseases such as cardiovascular disease, diabetes, and cancer are among the leading causes of death, so researchers are striving to find new efficient treatments for these diseases (2).
The causes of obesity
A high-calorie diet is a causal factor in obesity and may also lead to alterations in the gut microbiome (3). In addition to dietary, lifestyle, and genetic factors, it is suspected that obesity may also result from a disruption of the gut microbiome, which affects metabolic function and the balance between food intake and energy expenditure (3).
The Role of the Gut Microbiome on Health
It is well known that the gut microbiome has a tremendous impact on overall health and well-being. The bacteria in the gut influence the absorption, breakdown, and storage of nutrients and have potential effects on physiology (1). In addition to high caloric intake, overuse of antibiotics has also been linked to the occurrence of obesity (4). An imbalance in the gut microbiome, which is also known as dysbiosis, can promote the growth of harmful organisms that can cause chronic inflammation and thus plays an important role in the prevention of chronic metabolic and intestinal diseases (5). A balanced gut microbiome on the other hand, is considered an important factor in the prevention or alleviation of obesity and metabolic diseases (6). Thus, increasing beneficial bacteria while reducing harmful bacteria can contribute to better health and well-being (7).
The microbiome determines appetite
The intestine has come to be called the “second brain” because the microorganisms living there communicate directly with the brain and thus influence brain signals that are responsible for stimulating hunger and appetite (8).
It’s all about the right ratio
In most studies, the ratio of Firmicutes to Bacteroidetes was found to be significantly higher in obese subjects (7). In addition, a study was conducted to investigate the differences in the gut microbiome between obese and nonobese Japanese subjects. Obese subjects had a significantly reduced number of Bacteroidetes and a higher ratio of Firmicutes to Bacteroidetes compared with nonobese subjects. Bacterial diversity was also lower in obese subjects than in nonobese subjects (9).
A study of obese and lean Chinese college students showed a negative correlation between BMI and diversity. Obese male subjects had a less diverse microbiome than individuals in the lean group. In addition, the composition of the microbiome in lean males was more complex and had a higher ratio of Bacteroides to Firmicutes.
With myBioma you can learn how your microbiome utilizes your calories and how it stands around your diversity. Learn here more.
The Influence of Diet.
Different diets have a different impact on the composition and diversity of the gut microbiome (10). In this context, the typical Western diet, which consists of the consumption of highly processed foods, a high intake of saturated fatty acids and sugars, and a low intake of vegetables, fruits, and fiber (11), upsets the gut microbiome (12).
Studies have shown that African children who eat a low-fat, high-fiber diet have higher diversity and fewer disease-causing bacteria. These children also have greater amounts of Bacteroidetes than European children, who have greater amounts of Firmicutes and Enterobacteriaceae (13).
In contrast, a high-fat, low-fiber diet has been shown to reduce gut microbial diversity (14), protective gut bacteria, and SCFA (short-chain fatty acids) (15). Intake of high-fiber foods (e.g., fruits, vegetables, and legumes) increased microbial diversity (14, 16) and was associated with reduced weight gain in humans, independent of caloric intake (17).
In addition, astaxanthin, one of the most potent antioxidants, and the medicinal mushroom Antrodia cinnamomea were shown to improve the gut microbiome in obese mice induced by a high-fat diet. Both prevented weight gain, improved fat and sugar metabolism, and regulated the balance of the gut microbiome (18, 19) by optimizing the ratio of Bacteroides to Firmicutes and improving Akkermansia (19).
The influence of movement
Sports activities have a positive influence on the gut microbiome. They promote microbial diversity and also the proliferation of butyrate-producing gut bacteria (20). One study compared changes in gut microbial diversity and composition in young adults engaged in moderate to intense physical activity. The study found an increase in microbial diversity, particularly in participants who also ate an adequate amount of fiber per day (21). In addition, an increase in Bacteroidetes and a decrease in Firmicutes were reported in obese adults after aerobic moderate to intense physical activity (22). It can be concluded that both exercise and a high-fiber diet have a positive effect on our “slimming bacteria.”
Taking a holistic view
Finally, several factors influence the diversity and composition of the gut microbiome and can lead to an imbalance associated with weight gain and obesity. In particular, diet, physical activity, dietary supplements, medications influence the gut microbiome. The influence of the gut microbiome on metabolism, hormone balance, and the brain may play an important role in weight control and obesity treatment..
We are already excited to see more studies. In our next blog article we share with you a microbiome recipe to increase your healthy slimming bacteria. Be excited!
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