Diets that reduce caloric intake have been proven to not only help prevent metabolic disease, but may also have positive results on immune function. A recent study demonstrated this via changes to gut microbiome that delay immune system deterioration as we age.
The gut microbiome is the collective collection of all digestive tract bacteria and microorganisms; these organisms affect our metabolism and immune systems in numerous ways, from metabolic regulation to immune defense.

Over 2 billion individuals worldwide are overweight. Obesity raises the risk of heart attack, high blood pressure and type 2 diabetes and may contribute to inflammation that weakens immunity by means of memory T and B cells accumulating – this change occurs naturally with age and is known as immune senescence.

Diets that help obese individuals delay metabolic diseases like type 2 diabetes may also have positive effects on immune systems and have been found to delay development of metabolic diseases like type 2 diabetes, although how the gut microbiome mediates these positive effects remains unknown. Researchers have now conducted studies analyzing interactions among calorie-reduced diets, metabolism, gut microbiomes and immunity systems.

Researchers first studied how an obese woman’s gut microbiome was altered by an extremely low-calorie diet of 800kcal per day for eight weeks. After that period had ended, their researchers transplanted her gut microbial community before and after eating this diet into germ-free mice to create a “gnotobiotic mouse model”, in order to better assess how its changes impacted metabolism as well as immune function.