What happens when you eat a lot of fermented foods?

Fermented foods and drinks can improve digestion, boost immunity, and aid in weight loss. Commonly consumed ones include kombucha (fermented tea), sauerkraut, tempeh, natto (Japanese fermented soybeans), miso, kimchi, and sourdough bread.

Fermented foods contain a variety of microorganisms, such as live bacteria and yeasts (probiotics), some of which are harmless or beneficial. During fermentation, probiotics convert carbohydrates (starches and sugars) into alcohol or acids. They act as natural preservatives, giving foods a distinctive flavor.

In addition to probiotics, other factors that influence the fermentation process are metabolites such as lactic acid and amino acids. Fermented foods may have many health benefits, but they are not for everyone. For some people, fermented foods, especially those rich in probiotics, can cause health problems.

Flatulence

The most common reaction after consuming fermented foods is bloating. This is the result of excess gas produced after probiotics kill harmful gut bacteria and fungi. Probiotics secrete antimicrobial peptides that kill harmful, disease-causing organisms such as salmonella and e.coli.

Recent research has shown that regular yogurts are rich in probiotic Lactobacilli, which have antibacterial properties. Bloating after consuming probiotics is a good sign that harmful bacteria are being eliminated from the gut, but some people may experience severe abdominal pain. Drinking too much kombucha can also lead to excess sugar and calories, which can cause bloating.

Headache or migraine

Probiotic-rich foods like yogurt, sauerkraut, and kimchi contain biogenic amines, which are produced during fermentation. Amines are produced by some bacteria that break down amino acids. Common substances in probiotic-rich foods are histamine and tyramine.

Some people are sensitive to histamine and other amines. They may experience headaches after eating fermented foods. This is because amines stimulate the central nervous system, which can increase or decrease blood flow, causing headaches or migraines. One study found that a low-histamine diet reduced headaches by 75%.

Foodborne illness

Most fermented foods are safe, but they can still be contaminated with disease-causing bacteria. In 2012, 89 people in the US were infected with salmonella after eating unpasteurized tempeh. Salmonella infection is common and can occur at any age. The disease comes from many different sources and presents with many unpleasant symptoms, typically diarrhea and abdominal pain. If left untreated, this condition can lead to dangerous complications and even death.

In 2013 and 2014, South Korea also recorded two outbreaks of E. coli infections at schools due to students eating kimchi and fermented vegetables. The disease caused urinary tract infections, intestinal infections, and infections of many other organs.

In most cases, probiotics in foods like cheese, yogurt, and buttermilk prevent the growth of harmful bacteria. But in some cases, probiotics don’t work, and bacteria can produce toxins that are dangerous.

Infection from probiotics

Probiotics are generally safe, however, in some cases they can cause infections, especially in people with compromised immune systems.

A study in London reported that 65 patients developed liver abscesses after consuming probiotics. Susceptible patients are advised not to use too much probiotics. These probiotics can cause serious infections, such as pneumonia, systemic infections, sepsis, and endocarditis.

Antibiotic resistance

Probiotic bacteria can carry antibiotic resistance genes. These genes are passed on to bacteria in the food chain and the human digestive tract. The most common antibiotic resistance genes in fermented foods are those that inhibit erythromycin and tetracycline, which are commonly used to treat some respiratory diseases and sexually transmitted diseases.

Researchers have also found many drug-resistant strains of probiotics in commercially available dietary supplements. This puts them at risk of reaching the public. A recent Malaysian study found that probiotic lactobacilli in the fermented nutritional drink kefir were resistant to ampicillin, penicillin, and tetracycline. These are antibiotics used to treat bladder infections, pneumonia, gonorrhea, and meningitis.