Letting bacteria thrive in our food might sound counterintuitive, but fermentation is an ancient preservation technique that fosters beneficial microbes essential for health.
Yogurt, sourdough bread, sauerkraut, and pickles have surged in popularity lately. Fermentation, used long before refrigerators existed, extends food shelf life. Natural or added ferments (like rennet, sourdough, or kefir) acidify foods, inhibiting harmful bacteria and fungi. This process alters flavor and enhances nutritional value.
Fermentation transforms food composition (see box 1). It breaks down antinutrients that block absorption of minerals like calcium, zinc, and iron, making them more bioavailable. Vitamins, especially B12 (cobalamin)—vital for red blood cell production and nerve function—increase. It also speeds digestion and nutrient uptake. Opt for sourdough over yeasted bread, as it degrades hard-to-digest phytic acid. Lactose-intolerant individuals often tolerate yogurt and cheese better than milk.
Fermented foods teem with microbes. Can they diversify our gut microbiota—the community of bacteria, yeasts, viruses, and fungi that supports immunity? A Stanford University study followed 18 people on a fermented-food-rich diet for 10 weeks. Results, published in Cell (July 2021), showed greater microbial diversity and lower inflammation markers. While promising, it doesn't yet prove protection against diseases like diabetes; research continues.
The Different Types of Fermentation
Lactic (lacto-) fermentation converts sugars to lactic acid—unrelated to lactose despite the name. Used for dairy (yogurts, cheeses), cured meats, mushrooms, and veggies (cabbage, beets, carrots). Alcoholic fermentation turns sugars into ethanol, as in bread, beer, and wine. Acetic fermentation converts ethanol to acetic acid, yielding vinegar.
Beware of Unproven Claims
"Boosts immunity," "Strengthens defenses," "Activates health," "Balances gut flora"—no such claims for fermented foods are EFSA-approved. Only two yogurt ferments are recognized for easing lactose intolerance.
