Fermented Food
Sharon Nicholson, M.S, R.D, LDN, with over 40 years experience as senior clinical dietitian at St. Elizabeth’s Medical Center, writes about diet and nutrition for seniors.
Question: While humans have been fermenting
food for thousands of years, what evidence
supports the health benefits?
Answer:
Fermentation involves the addition of bacteria, yeast, or mold which adds flavor and delays spoilage. In some foods, organisms remain alive, while in others they are destroyed during processing. Foods that are products of fermentation include: dairy, such as most cheeses, milk-based yogurt, kefir, cream cheese, and sour cream; soy products, like tempeh, miso, and soy sauce; fermented cabbage, such as kimchi and sauerkraut; kombucha tea; some vinegars, such as rice and apple cider; and sourdough bread.
While beer and wine are also fermented, current medical recommendations advise cautious and limited alcohol consumption.
What Is Actually Known About the Benefits of Fermentation?
Sometimes it allows certain hard-to digest foods to be better tolerated. For example, those with lactose intolerance may be able to consume yogurt and kefir without discomfort. Sour dough bread can be a good choice for individuals with gluten sensitivity or irritable bowel syndrome (IBS).
However, many health claims are not clearly supported by scientific fact. Example: In 2024 the Food and Drug Administration allowed makers of dairy-based yogurt to state, “based on limited evidence”, that consuming two cups/week of this product MAY help to decrease the risk of developing Type 2 diabetes. Like these yogurt studies, conclusions about the benefits of fermented foods are suggestive but not definite.
While further investigation is needed, evidence points to advantages when microbes in fermented food are alive and able to possibly support the body’s microbiome. The microbiome itself consists of bacteria, fungi and other organisms that live primarily in the colon/large intestine and play an important role in maintaining health. Its many functions include protecting against and fighting infection, blocking chronic inflammation (involved in many illnesses that develop with aging), and supporting healthy brain function (another concern as we age).
Health Precautions Associated with Fermented Foods
While fermented foods can be a good choice for some individuals, others may need to exercise caution.
Kimchi, miso and sauerkraut are high in salt, a concern for those with high blood pressure, heart failure, and kidney problems. Kombucha often contains a lot of “added sugar” (read label). Those with diabetes should be especially mindful. The American Heart Association has strict guidelines for daily added sugar intake (2 tablespoons/day for women, 3/day for men). Those with compromised immune function should get medical advice concerning the safety of fermented foods with live cultures. This includes people on chemotherapy, high dose steroids or other immune-suppressing drugs, and organ transplant recipients.
Others who should get advice include folks with SIBO (small intestinal bacterial overgrowth). Individuals taking MAO inhibitors or experiencing histamine intolerance should avoid fermented foods.