How does fermentation affect digestive symptoms?

Fermentation is a natural process in which micro-organisms break down carbohydrates (sugars) into acids, gases or alcohol. Although fermentation is often associated with fermented foods such as yogurt, kimchi or sauerkraut, it can also occur in the digestive system, influencing gastrointestinal symptoms.

Understanding fermentation

When carbohydrates are not fully digested in the small intestine, they pass into the colon and become a food source for the bacteria of the intestinal microbiota. These bacteria metabolize the carbohydrates via a fermentation process, producing gas and other compounds such as short-chain fatty acids (SCFA).

Impact on digestive symptoms

In some people, this fermentation can lead to unpleasant digestive symptoms such as bloating, gas, abdominal cramps, diarrhea or constipation. Individuals suffering from irritable bowel syndrome (IBS) (or often referred to as irritable bowel syndrome) are particularly susceptible to these effects, as their digestive systems can overreact to carbohydrate fermentation. This concept of fermentation refers to the FODMAP. For more details on this diet, see the blog on Irritable bowel syndrome: Beyond FODMAPs, what are the different avenues of intervention?

Fermented foods

Not all the effects of fermentation are negative. In fact, it optimizes the nutrient content of certain foods, such as bioactive peptides and vitamins, and improves digestibility. What's more, some fermented foods contain "live" bacteria that appear to help promote better digestive health, but more studies are needed to confirm this. Yogurt, kefir, miso and tempeh are just a few examples of fermented foods.

Symptom management

If you're experiencing digestive symptoms linked to fermentation, there are several strategies you can adopt to manage them. Reducing consumption of gas-producing foods, such as cruciferous vegetables (broccoli, cauliflower, cabbage, turnip), legumes, garlic and onions, can help alleviate symptoms in some people. Diet low in FODMAP can also help manage gastrointestinal symptoms. However, there's no point in limiting consumption of these foods if you don't observe any associated symptoms. Prolonged restriction of fermentable foods (such as FODMAPs) appears to have negative effects on the diversity of the intestinal microbiota. Accompaniment is essential to ensure a personalized approach to managing symptoms and meeting nutritional needs.

This blog is a summary of the subject. For further information and scientific references, see this complete blog and the document on The ABCs of fermented foodsavailable on the webshop.