Promote "good intestinal dwellers": fiber, yoghurt, polyphenols
The intestinal flora (microbiota) affects health more than has long been suspected. Whether positive or negative depends mainly on the diet: plenty of vegetables, legumes and whole grains promote a cheap microbiota with a wide spectrum of bacteria and a high proportion of protective (protective) germs. In contrast, a typical western diet high in fat and protein with little fiber favors the growth of bacteria that form toxins, fire inflammation and weaken the intestinal barrier.
The constituents in which the intestinal bacteria react have been the subject of intensive research in recent years: "Dietary fibers are the key to a healthy microbiota," says Dr. Maike Groeneveld, practice for nutritional advice in Bonn. Water-insoluble fibers such as cellulose bind a lot of water and thus promote the exchange of materials and the »teamwork« between individual types of bacteria. The intestinal bacteria break down soluble fiber such as pectins into short-chain fatty acids, which have a positive effect on the intestinal environment. Some fiber such as inulin and oligofructose specifically stimulate the growth of useful bifidobacteria. Whole grains with a naturally high fiber content increased the proportion of bifidobacteria in a study with 80 healthy overweight people, while the inflammatory martens decreased.
Polyphenols such as anthocyanins in berries or flavonoids in apples and onions also promote the growth of bifidobacteria. »Only 5 to 15 percent of these secondary plant substances are absorbed in the small intestine; the lion's share gets into the large intestine, «explains Groeneveld. And there they have their positive effect.
Certain additives may have negative effects on the microbiota. This is supported by some studies, but the data situation is still too thin for clear conclusions. "Nevertheless, the influence of additives on the microbiota should be included in the risk assessment in the future," Groeneveld demands.
Clearly bad effects have pathogenic (disease-causing) germs on the microbiota. Above all, the frequent trigger of diarrheal diseases Campylobacter jejuni has a long-lasting effect - inflammation cells in the intestine are still detectable months after an infection has subsided. In the long term, an infection can increase the risk of inflammatory bowel diseases, and irritable bowel patients also often experience gastroenteritis before diagnosis. The aggressive germs are often transmitted via insufficiently heated, contaminated food, mostly poultry. "Infections can be avoided with careful hand and kitchen hygiene," advises Groeneveld. In contrast, fermented milk products such as yogurt, probiotics and kefir contain protective bacteria. Your daily consumption contributes to a stable microbiota. Dorothee Hahne, aid