• An epidemiologist and nutrition expert eats at least three fermented foods each day for gut health.
• Tim Spector shared his tips on how to incorporate fermented foods into your diet.
• These include starting small, checking food labels, and "backslopping."

You may have noticed a proliferation of kefir and kombucha in stores lately. Fermented foods are everywhere, but can be a little intimidating to people who aren't used to them.

Tim Spector, a British epidemiologist and cofounder of the nutrition company Zoe, eats at least three different types of fermented foods every day to aid his gut health.

Research on fermented foods is still developing, but, according to a 2022 review in the journal Nutrients, studies suggest that they can reduce risks of cardiovascular disease and type 2 diabetes, and increase the diversity of bacteria in the gut. The gut thrives on a varied diet, so this diversity is important for digestive and overall health.

Spector told Business Insider how he incorporates fermented foods into his diet.

Start small

"Little and often" is the best way to start adding fermented foods to your diet, Spector wrote in his cookbook "Food For Life," which is due to be published in the US in 2025.

This allows you to get used to the taste and your gut to get used to all the new bacteria.

Spector recommends adding a tablespoon of different fermented foods to your cooking — for example, kimchi in a stew for "flavor and crunch," or kefir to a soup for "creaminess and tang."

This chimes with what other experts told BI: Tanzil Miah, a dietitian specializing in gut health, said adding kimchi or sauerkraut to sandwiches or salads, and using yogurt as a sauce or marinade are easy ways to add fermented foods to what you're already eating.

Check out labels of shop-bought fermented foods

"My advice to the fermenting newcomer is to find some commercial fermented products you enjoy and slowly work up to fermenting your own," Spector wrote in "Food For Life."

When buying shop-bought fermented foods, such as kefir, kombucha, sauerkraut, or kimchi, he recommends looking for products that are:

• Low in added sugar.
• Have few/no chemical additives.
• Not pickled in vinegar, which kills live microbes.

Then make your own

When you're ready, Spector said you can expand the scope of fermented foods away from just pickles and kefir. He now makes his own homemade labneh and a fermented mushroom-and-garlic spread, for example.

Making fermented foods at home is also great for the environment and your wallet because it reduces food waste, he said.

And it's easy. "You can ferment just about any plant," he said, using only salt or honey.

BI previously reported a Michelin-star chef's techniques for making homemade kimchi, sauerkraut, and pickles.

Or, Spector said, you can make your own kefir from the dregs of a store-bought bottle with a technique called "backslopping." To backslop kefir, add a tablespoon of good-quality kefir to a bottle of full-fat milk, leave it at room temperature until it thickens, and then store in the fridge.