A weak immune system can cause an imbalance in gut bacteria, leading to increased fat absorption and weight gain. While high energy intake is meant to help fight diseases, it often leads to obesity and can even be contagious. According to a study by the World Health Organization (WHO), approximately 1.9 billion adults worldwide are overweight, with 650 million suffering from obesity. Experts predict that by 2045, a quarter of the world’s population will be obese. While the causes of obesity are not fully understood, studies have shown that gut bacteria play a significant role in metabolism. Researchers at the University of Utah have now discovered that the gut microbiome is also influenced by the immune system.
Previously, it was known that bacteria responsible for metabolism were hindered by antibiotics, a diet lacking in fiber, and excessive hygiene. However, the discovery that the immune system also affects metabolism was accidental. Researchers found that mice with weakened immune systems became significantly heavier than genetically unaltered mice under the same diet and living conditions. The scientists concluded that the weakened immune system negatively affects the gut microbiome. Further investigation showed that in mice with weakened immune systems, antibodies no longer docked to gut bacteria to the same extent as in animals with a completely intact immune system. This leads to an imbalance between the different bacteria in the microbiome, which in turn affects health and metabolism responsible for obesity.
The study also found that an unbalanced gut microbiome can be contagious, as non-genetically altered mice that shared cages with genetically altered mice also became overweight. The new findings are relevant to humans, as overweight individuals often have a weak immune system and a low number of Clostridia bacteria in the gut. Combining these factors with known causes of obesity and related diseases such as type 2 diabetes could lead to new approaches for prevention and treatment.
