Nutrition is one of the most important factors affecting intestinal composition and metabolism. Factors such as the amount of nutrition, the type of nutrition, the distribution percentages of carbohydrates, fats and proteins, which are macronutrients, the transit times of foods through the intestine and pH values are effective on the intestinal microbiota.
The effects of food groups on gut health are different from each other. To look at the effects of different food groups separately;
Fibers can improve the microbiota profile by changing the intestinal environment and positively affecting the growth of beneficial microorganisms. Prebiotic fibers improve the profile of beneficial bacteria in the colon by stimulating the growth of probiotics such as lactobacilli and bifidobacteria. It is known that the short-chain fatty acids produced by the intestinal microbiota have positive effects on human health by regulating intestinal homeostasis and providing optimum immune function. These improvements in the intestinal microbiota play an active role in many health problems such as irritable bowel syndrome, obesity, cardiovascular health.
A diet rich in fiber can have a protective and therapeutic effect against constipation. Therefore, daily consumption of 20-30 grams of fiber and adequate fluid intake is recommended.
However, fiber is not used therapeutically in all cases. Because fermentable fibers such as oligocarides and inulin can increase symptoms of irritable bowel syndrome, a low-FODMAP diet, i.e. diets that restrict fermentable fibers, may be required in these cases.
Unlike IBS, fiber consumption should not be restricted in inflammatory bowel disease.
To summarize briefly, accepted dietary guidelines recommend that fiber consumption should be at least 20 grams per day for a healthy gut.
Diets high in fat and high in saturated fat can have negative effects on the gut microbiota and lead to an unhealthy metabolic state.
Also, while high MUFA diets may adversely affect gut microbiota, PUFA does not appear to adversely affect gut microbiota or metabolic health outcomes.
Protein metabolism is closely related to the gut microbiota. Dietary proteins are metabolized by proteases and peptidases secreted from the small intestine, and the resulting amino acids can be used for protein synthesis by intestinal bacteria.
Undigested protein and amino acids are fermented into various bacterial metabolites, mainly short-chain fatty acids hydrogen sulfide and ammonia. Some of these bacterial metabolites can be transported within colonocytes and may exert beneficial or deleterious effects on epithelial cells depending on their toxic potential and concentration.
The type of protein in the diet, its concentration and amino acid balance can affect the composition of the gut microbiota. Consumption of adequate protein from the right sources contributes to intestinal health and immune system by supporting the intestinal microbiota.
Complex carbohydrates are fermented by microorganisms in the large intestine and, in addition to being used as an energy source, they positively affect the microbiota composition and metabolic activities by supporting the development of healthy microorganisms.