A Beginner’s Guide to Fermented Foods

Fermented foods have been part of traditional diets around the world for thousands of years. Today, yogurt, kefir, sauerkraut, kimchi and miso are easy to find in most supermarkets. If you’re curious about adding them to your meals, this beginner’s guide explains what they are, how to choose them, and simple ways to enjoy them.

What are fermented foods?

Fermentation is a process in which microorganisms, such as bacteria and yeasts, break down sugars in food. It changes the food’s flavor and texture. It’s what gives yogurt its tang and sauerkraut its sour crunch. Fermentation was traditionally used to help preserve food.

Some fermented foods still contain live microorganisms when you eat them, often called “live cultures”. Research into fermented foods and the gut is an active and developing area. Fermented foods can be part of a varied, balanced diet, but they aren’t a cure-all.

Common fermented foods to try

• Yogurt: look for plain yogurt labeled “live” or “with live cultures”. Plain varieties let you control any added sugar.
• Kefir: a tangy fermented milk drink, a little thinner than yogurt. Non-dairy versions are also available.
• Sauerkraut: finely shredded fermented cabbage.
• Kimchi: a Korean dish of fermented vegetables, usually cabbage, often with chili and garlic.
• Miso: a savory fermented soybean paste used in soups, dressings and marinades.
• Tempeh: a firm fermented soybean product that can be sliced and pan-fried.

How to choose them

Check for live cultures

Not all fermented foods contain live cultures. Many jarred and canned products are heat-treated (pasteurized) after fermentation to make them shelf-stable, and baking kills the cultures in sourdough. If live cultures matter to you, look for words like “live” or “unpasteurized” on the label. These products are usually found in the chilled section.

Watch the salt and sugar

Sauerkraut, kimchi and miso can be high in salt, so a small portion is plenty. Flavored yogurts and kefirs can contain a lot of added sugar, so plain versions are usually a better everyday choice. Add your own fruit for sweetness.

Easy ways to add them to meals

• Breakfast: top plain yogurt with berries and oats, or add kefir to a smoothie.
• Lunch: add a spoonful of sauerkraut or kimchi to a sandwich, wrap or grain bowl.
• Dinner: stir a little miso into soups or dressings at the end of cooking, or pan-fry tempeh for a stir-fry.
• Snacks: make a quick dip with yogurt, garlic, lemon and herbs.

Start small

If fermented foods are new to you, start with small portions, such as a tablespoon of sauerkraut or a small glass of kefir, and see how you feel. Strong flavors like kimchi can take a little getting used to.

Part of a bigger picture

Fermented foods are just one part of everyday digestive wellness. A varied diet with plenty of fiber from vegetables, fruit, whole grains, beans and lentils, along with enough fluids and regular movement, is the foundation. Read more in Why Fiber Matters in a Balanced Diet and Everyday Foods That Support Digestive Wellness.

A note on safety

If you are pregnant, have a weakened immune system, or have a digestive condition, check with your doctor or a registered dietitian before adding fermented or unpasteurized foods to your diet. If you have ongoing digestive symptoms, please see a healthcare professional rather than changing your diet on your own.

Further reading

• NHS, Good foods to help your digestion
• NHS, Salt: the facts