People with weakened immune systems, such as those undergoing chemotherapy or individuals who have had an organ transplant, along with individuals who have digestive disorders like irritable bowel syndrome or inflammatory bowel disease, should approach fermented foods with caution. This caution is particularly important for foods such as sauerkraut and other probiotic-rich products. This guidance reflects statements from a British nutritionist, Bachy Van de Boer.
Fermented foods are created through microbial fermentation. In practical terms, they are foods that have been exposed to bacteria in a controlled environment, resulting in distinctive flavors and textures. Some fermented products, including yogurt, fermented vegetables, and kefir, contain probiotics. Probiotics are beneficial bacterial strains that can support gut health and the balance of intestinal microbes.
Nevertheless, not every fermented item is appropriate for everyone. For people with compromised immune defenses, certain fermented foods should be consumed carefully. The nutritionist noted that some items, such as kimchi, which is mainly fermented vegetables like Chinese cabbage, and certain artisanal cheeses, may harbor bacteria that show resistance to antibiotics.
Antimicrobial resistance occurs when microbes adapt to withstand the effects of drugs. If such resistant bacteria enter the body, they can pose significant health risks. For example, a bacterium known as Weissella has been associated with potential infections that affect the heart lining, called endocarditis, and certain bone infections, including osteomyelitis.
Individuals undergoing chemotherapy or those who have had donor organ transplants are identified as being at higher risk for infections caused by these resistant bacteria. The concern extends to people with digestive disorders such as IBS and IBD, who may experience flare-ups when consuming fermented or dairy-based products. In these conditions, abdominal bloating can become severe and painful, underscoring the need for cautious dietary choices.
When probiotics are consumed, their cell components interact with the gut environment. Some of these interactions can release small protein fragments that influence the activity of the intestinal ecosystem, sometimes contributing to increased gas production and bloating in susceptible individuals.
Additional guidance emphasizes that dietary habits promoting overall immune resilience and gut health remain important for adults. Health professionals often highlight balanced nutrition, mindful food choices, and awareness of how specific foods interact with existing digestive conditions. In the context of cancer care and post-transplant recovery, personal medical advice takes priority, ensuring that any fermented foods align with individual treatment plans and health goals.
Experts continue to study the role of gut microbes in health and disease. Ongoing research aims to clarify which probiotic strains confer the most benefit for specific conditions and how to minimize potential adverse effects in vulnerable populations. This evolving field reinforces the importance of individualized dietary strategies and consultation with healthcare providers when managing immune function and digestive health.