Digestive health is essential for a healthy body. There are billions of bacteria in our digestive system, more precisely the intestines. Many of these bacteria, which are called probiotics, are necessary and highly beneficial. Probiotics are involved in the final and very important phase of digestion; they protect the body against pathogens by suppressing their growth with metabolic activity; they aid in the synthesis of some vitamins B and vitamin K; and are central to the normal functioning of the immune system. Beside beneficial bacteria, the intestines also house harmful ones. In fact, it is the balance between beneficial and harmful bacteria that determines the function of the digestive system and thus health in general.
Numerous factors can ruin this balance, such as unavoidable exposure to stress, a poor and unbalanced diet, physical and mental exhaustion, chronic medical conditions, and medications, particularly antibiotics. This can cause an increase in “bad” bacteria, leading in turn to a number of health issues, including diarrhea, constipation, bloating, vitamin and mineral deficiencies (due to reduced intestinal absorption), and a weakened immune system. In other words, intestinal microbiota are constantly undergoing transformation; therefore they must be regularly replenished. Prebiotics, or nourishment for beneficial bacteria, can be of great help.
Prebiotics are indigestible parts of plant foods (carbohydrates) – commonly sourced from Jerusalem artichokes and chicory. They feed beneficial bacteria, helping them to outnumber the potentially harmful bacteria. For this reason, they are added to fermented dairy products to improve the survival rate of probiotics. They can also serve as a replacement for sugar and fat. Another of their advantages is the low glycemic index value, which makes them suitable for diabetic patients.
Inulin and oligofructose are two of the most studied prebiotics. Numerous in vivo studies have demonstrated their beneficial effect on the intestinal microbiota balance. Inulin and oligofructose promote the growth of lactobacilli and bifidobacteria, which have been proven to confer a number of benefits to the body. In turn, strains of bifidobacteria and lactobacilli are also some of the most commonly used probiotics. There are other prebiotic substances in addition to inulin and oligofructose.
Some types can be found in foods that we consume daily.
One popular source is chicory root, which tastes similar to coffee, yet contains no caffeine. It is a rich prebiotic source, with inulin comprising up to 47% of the dietary fibre of the root. Onions and garlic are delicious plants with many health benefits. Inulin accounts for around 10% of the dietary fiber content of onions and garlic, while fructooligosaccharides (FOS) make up around 6%. Some studies have shown that onions and garlic act as prebiotics by promoting the growth of beneficial bifidobacteria, which suppresses the growth of potentially harmful intestinal bacteria. Barley and oats contain beta-glucans. There is a number of studies on beta-glucans, some of which have shown that the beta-glucans in barley and oats promote the growth of probiotics of the genus Lactobacillus.
Bananas have been extensively studied as well. Unripe (green) bananas are high in so-called resistant starch, whose prebiotic effect has been scientifically proven.
A diet rich in prebiotic foods can significantly contribute to the healthy balance between beneficial and harmful intestinal bacteria, and in turn support a healthy body.