Q: I've heard a lot about the benefits of fermented foods. What, exactly, are they, and what do they do for you?
A The gut is the largest component of the immune system, and there is evidence that gut health can affect inflammation, allergies and autoimmune disorders in the whole body. Fermented foods have been part of the human diet for centuries, derived mainly for the purposes of preserving foods in the days when there was no refrigeration. In fermentation, bacteria or yeast feed on the natural sugars in foods, and create compounds such as lactic acid or alcohol, which help preserve the foods. The end product is filled with "friendly" bacteria (think: probiotics) and gut-friendly enzymes. The bacteria predigest certain food components, which makes it easier for your gut to handle and for nutrients to be absorbed when you eat them. Common fermented foods include yogurt (especially Greek yogurt), kefir, pickles, sauerkraut, kimchi, miso, soy sauce and tempeh. Just be sure to check the sodium and sugar content of the fermented foods you purchase.