Fermented foods: good for the gut, bad for cancer



Fermentation is a chemical process that keeps foods from spoiling, but it has other benefits, especially when we are fighting or recovering from illness. Fermentation produces bacteria called probiotics that are good for the gut, boost our immune system, and help free up more nutrients to be digested and used by our bodies. And if you love grains, know fermentation reduces their gluten and lectins—the not-so-healthy stuff in them.


Research shows probiotics influence hundreds of our genes, helping them express in a way that fights disease

For instance, they help curb a protein that causes cancer-promoting inflammation, according to alternative physician Dr. Joseph Mercola. 

Unfortunately, you won’t find many fermented foods in most grocery stores, especially in the United States. But here are some good ones still on the shelves, they are most commonly found in health foods stores and in some Indian and Asian grocery shops.


Good fermented foods

Dietician Gale Maleskey recommends sourdough bread; pickled vegetables like German sauerkraut, natto (Japanese soybeans), kimchi (Korean dish with cabbage, other vegetables and spices), and tempeh (Indonesian dish derived from fermented soybeans.) There’s dark chocolate, aged cheeses, pickled and cured olives, and yogurt (full-fat Greek yogurt or strain your own to cut out the sugars).

You’ll get added benefits with some of these foods. Sourdough bread is a classic example: it has a lower glycemic index than other breads, helping reduce insulin spikes, which gives sugar-loving tumors less to feed off of, and boosts immune strength.

Organic yogurt has healthy protein and carbs, associated with better immunity and reduced risk for colon cancer. And with dairy in general, fermentation breaks down milk sugar lactose, helping with insulin levels and digestion. 


“Just don’t overdo it because the saturated fats in dairy can cause inflammation, which is not good for cancer,” she says, adding to avoid milk that is mass manufactured because it’s injected with hormones and antibiotics.


Be sure you’re buying real fermented foods

Shop at organic food stores, Asian markets or major supermarkets that can tell you the food isn’t pasteurized or homogenized; these processes destroy health-promoting microorganisms. 

Some of these products are available online, through Berkeley Bowl in the US, Cold Storage in Singapore, or other on-line “stores” (e.g., Amazon.com sells raw, organic sauerkraut).


Know some fermented foods may be safer than others

“With some products, probiotics are added by food manufacturers (called seeding). Then there are probiotics from wild fermentation, where the food is left open to the air to take up microbes,” says Gale.

“Wild fermentation can result in spoiled food. I recommend someone with cancer sticks with the seeded foods to know exactly what’s in them, and to get their full benefits,” she says. 


More information:

Ideas for fermented dishes



Probiotics and cancer



Health benefits of probiotics



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3 Responses to “Fermented foods: good for the gut, bad for cancer”
  1. Idelle says:

    This is really good information, Rachel. I agree with Gale that it’s important to consume non-hormone treated dairy. One way to ensure that is to look for labels that read “not from rBST treated cows,” or purchase organic dairy products.

  2. Tami Boehmer says:

    Great article, Rachael! I really love that sourdough bread is on the list! Yum!

  3. I have some pickles in the fridge and am really hoping they fall into this category. And Greek yogurt? I had no idea! Thanks for this informative post.

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