Probiotics are beneficial to health microorganisms living in the intestinal tract. They are important for good digestion and absorption of food. In contrast, prebiotics are not living organisms, but indigestible carbohydrates  in the form of dietary fiber . Prebiotics serve to feed the intestinal microbiome , the collection of colonies of bacteria , viruses and other intestinal microbes (probiotics).
Prebiotics support the function and growth of probiotics and provide optimal digestion for humans.
All prebiotics are fiber, but not all fiber is prebiotics. Only some fibers are water-soluble, in contact with water their chemical bonds are broken, they swell and form a gel with water. This type of fiber is rich in prebiotics, known as oligosaccharides, and contains substances such as inulin and oligofructose . These compounds are not broken down by human digestive enzymes or stomach acids and cannot be used by humans. Intestinal bacteria such as lactobacilli and bifidobacteria use these substances for food and metabolize them through fermentation processes .
In this way, prebiotics reduce the acidity of the stomach, retain and prolong the absorption of nutrients over time, their expansion in water gives them more volume, bringing a feeling of satiety and nourish healthy microorganisms.
Foods rich in prebiotics are: almonds , apples , bananas , garlic , onions , soy , wheat , corn , oats and more. According to clinical studies, the human body needs a daily intake of prebiotics up to 10 grams.
A varied diet rich in prebiotic fiber improves not only digestion but also the strength of the immune system , reducing the likelihood of developing colitis , a group of inflammations of the lining of the gastrointestinal tract, mainly affecting the intestines . Good health of the intestinal flora is necessary for the suppression of inflammatory processes in other tissues and organs, through prebiotics they are more active and have a preventive and depressing effect on the symptoms of asthma and rheumatoid arthritis .
The lack of prebiotics depletes the intestinal flora, which lowers its metabolic activity. The amount of substances synthesized by the probiotics on which the body relies decreases and metabolic problems associated with neurodegenerative diseases such as sclerosis and sleep disorders develop .
For good nutrition it is important to monitor the intake of prebiotics - exceeding the daily dose of a maximum of 10 grams can lead to an excess of inulin, which is associated with decreased gastrointestinal tolerance and increased gastric disorders .