Kimchi, yogurt, and other fermented food could trigger migraines, headaches, and food-borne illness
Kimchi, yogurt, and kombucha are some of the popular fermented items hailed for their health benefits. But a group of individuals may react badly to these fermented products, according to Manal Mohammed, lecturer of medical microbiology at the University of Westminster.
Mohammed says fermented products can trigger allergy-like symptoms and a host of other side-effects such as headaches, bloating, and migraines, in a small group of people. Further, it is possible for fermented products to get contaminated with bacteria that can cause illness. Hence, adopting a one-size-fits-all approach towards fermented products can be damaging, says the researcher.
"While there are a wide variety of health benefits that can happen from consuming fermented foods, these may not work for everyone. While most people will be fine eating fermented foods, for some, they could cause serious health problems," says Mohammed.
In the early days, fermentation was carried out to preserve food, enhance shelf life, and improve the flavor by introducing good microorganisms, such as live bacteria and yeast or probiotics. These microorganisms, in turn, convert carbohydrates into alcohol or acids - natural preservatives - while also giving fermented foods their distinct flavor.
Fermentation has come a long way since then, with its benefits extending beyond preservation. Armed with high amounts of good microorganisms, fermented foods have shown to fight inflammation, diabetes, harmful microbes and fungus.
The popularity of fermented products has skyrocketed in the recent past: the consumption of fermented foods was up a whopping 149% in 2018 in the US alone, according to Upserve, a tech-based restaurant management platform. The worldwide market is expected to be worth US$ 40 Billion by 2022. What is more, PepsiCo and Coca Cola have acquired mainstream brands of kombucha in the US and Australia.
Some of the most popular fermented foods include kefir, kombucha, sauerkraut, tempeh, natto, miso, kimchi, and sourdough bread.
Previous studies have shown that fermented products improve digestion, boost immunity, and even help people lose weight. According to health experts, these items may help boost the strength of gut microorganisms residing in the digestive tract. These organisms, according to research, have some role to play in health conditions from obesity to neurodegenerative diseases.
Accompanying these benefits are a few side-effects. The most common of them all is gas and bloating, which happens when microorganisms in the fermented products kill harmful bacteria and fungus. Although a good sign, bloating can be painful for some.
Some people are also sensitive to certain components present in fermented products such as "yogurt", "sauerkraut", and "kimchi", writes Mohammed. To break down the amino acids in fermented foods, bacteria produce amines, a component that alters blood flow, and thereby causes headaches and migraines in some people.
Besides amines, bacteria in fermented products also produce histamine, a component that alerts the immune system and, in some instances, sends the immune system into overdrive, triggering allergy symptoms. While some people can break histamine down, others cannot - these people end up with allergy symptoms such as itching, headaches or migraines, runny nose (rhinitis), eye redness, fatigue, hives, and digestive symptoms include diarrhea, nausea, and vomiting.
Fermented food products do not come without risks of contamination with harmful microorganisms. In 2012, an outbreak of 89 cases of Salmonella in the US occurred because of unpasteurized tempeh - an Indonesian soy product, Mohammed recalls. These products are even more dangerous to people with a weak immune system.
Further, these products could also contribute to the antibiotic-resistance crisis. According to Mohammad, six probiotic Bacillus strains found in food products - including kimchi, yogurt and olives - were also resistant to several antibiotics.