Do Fermented Foods Cause Cancer?

Some research has been floating around the web that shows a connection between fermented foods and esophageal cancer. If you enjoy fermented foods, this can be very disappointing news to hear. There are many health benefits to eating fermented foods. But if they also cause cancer, do we really want to be eating them?

A meta-analysis of available research performed across Asia concluded that regularly eating pickled foods doubles your chance of getting gastric cancer (GC). That’s pretty alarming! So should you ditch all of your ferments right now? Well, no. There’s much more to the story.

It’s widely known that a diet high in vegetables is excellent for cancer prevention. In Korea and Japan where these studies were performed, residents eat 34 to 73 percent more vegetables than Americans. The thinking is that with that high of a vegetable intake their GC rates should be lower than Americans’ but it’s not. That’s what the researchers wanted to uncover. Why is it not lower?

Do Fermented Foods Cause Cancer?

The research compares the risk of GC in those who eat a high amount of fresh vegetables and those who eat a high amount of pickled vegetables. One concern is that the studies don’t differentiate fermented foods from those pickled in vinegar. Foods processed with vinegar are not going to be as nutritious as fermented vegetables. Without this distinction, it’s really impossible to know if fermented vegetables would cause the same rate of high GC incidence.

There are other issues that the researchers bring up—pickled foods are high in salt and a high-salt diet can lead to GC. Another issue is that an acidic solution, like is found in vinegar-based pickled vegetables, can degrade the cancer-fighting effects of vegetables.

Even if fermented foods did cause these same issues, there’s still one part of the analysis that may not be clear to everyone who hears about this research. There’s a connection between high intake of pickled vegetables (with a lower intake of fresh) and GC risk, not any amount of pickled food and GC risk.

The researchers’ conclusion states, “A high consumption of fresh vegetables, rather than the total amount of vegetables, which includes pickled vegetables, should be promoted to reduce GC rates in Japan and Korea.” So basically, don’t substitute pickled vegetables for fresh. Keep eating lots of healthy fresh vegetables in combination with fermented veggies in addition. Not in place of.

The Answer is NO!

At the end of the day, we would need a lot more research to say that fermented foods were carcinogenic at all. We would need to know:

  • If fermented foods caused the same problem as pickled
  • If the ingredients in the pickled food were to blame (hot peppers and vinegar)
  • What the ratio of fermented foods to fresh vegetables eaten is, not just how frequently.

So, rest easy knowing that your fermented vegetables still carry their cancer-fighting benefits such as reducing inflammation. And know that your fermented vegetables, when included in a healthy, varied diet are still very good for you!


If you are just beginning your fermentation journey, and are unsure if it’s for you, try the Fermentools Starter Kit. Less expensive than a fermentation crock, the kit will turn your Mason jar into a fermentation vessel for a fraction of the cost.


Mindy Wood is a writer, wife, mother, and homesteader, living in the beautiful mountains of New Hampshire. She writes at Purposefully Simple where she shows people how to live more self-reliant and healthy lives by growing their own food and learning other homesteading skills.

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