I often receive emails asking me if I eat or drink foods that have been fermented. I used to make lots of homemade yogurts and also fermented vegetables because I was coming from the idea that these foods are traditional and that they would help us. I used to love… Kambucha! Well, what I found as I ate these fermented foods was that they really didn’t make me feel so well and I was confused to why.
Then I discovered the works of Dr. Raymond Peat, who has been studying and writing about nutrition for 40 + years and what I discovered is that fermented foods aren’t that healthy after all!
Reading Dr. Peat’s articles helped me to understand that lactic acid in fermented foods is actually stressful and inflammatory for the body and can really mess with your metabolism and its ability to make energy. Fermented foods are actually stressful to your entire system. Yes, it was fun to make them and to and to eat them. But, if you look at the cellular level and how lactic acid reacts to the cell: fermented foods are actually unhealthy. When our cells are stressed they make lactic acid. Our liver then needs to convert lactic acid to glucose- which takes a lot of energy. So for those of us that don’t have a fast metabolic rate – extra lactic acid in the system is just too much burden on a liver that is already dealing with a lot in this day and age of all kinds of toxins. Now, personally, I limit eating fermented foods.
When I consider these foods I think of quotes like this one by Dr. Raymond Peat: “The presence of lactic acid, which indicates stress or defective respiration, interferes with energy metabolism in ways that tend to be self-promoting. Harry Rubin’s experiments demonstrated that cells become cancerous before genetic changes appear. The mere presence of lactic acid can make cells more susceptible to the transformation into cancer cells. (Mothersill, et al., 1983.)”
Traditionally people ate fermented foods because they had no choice. Methods of the times used the production of lactic acid to preserve foods because there was no refrigeration. However, when you eat these foods, the lactic acid goes through your digestion and into your circulation. A buildup of lactic acid in the liver will overpower the organ and the liver, which becomes overworked, cannot do its job well.
If you are feeling well, a bit of lactic acid may be ok. But, it can also push the system over the edge. I believe most people can’t deal with much extra stress. Most people’s systems (at least people I work with) have been weakened by years of poor eating and stress. Historically, when people ate fermented foods, they may have had stronger systems; meaning their thyroids were stronger, having been breast fed for 4 + years. Now we have PUFA in the diet plus all kinds of toxic elements in the environment. Our system just can’t handle the lactic acid in the diet.
Ray Peat actually says he avoids all fermented foods. He stopped using black pepper (a fermented food, apparently) about 30 years ago when he saw the toxicity studies.
When I asked him recently about cottage cheese, he told me that if he suspects that his cottage cheese has a lactic acid dressing on it so he actually washes off his cottage cheese! He told me, “some have a ‘dressing’ with lactic acid added. If that’s the only kind available, I wash it until just the curds are left.” So what I understood from that statement, Dr. Peat avoids all fermented foods.
When I consulted with Dr. Ray Peat about the fermented foods and if they are safe, I asked him if he could help me to understand his thoughts. This is what he told me:
“Fermented vegetables, beans, and fish have been associated with cancer for a long time, and fungal toxins are the main carcinogens, but too much lactic acid is toxic, and even acetic acid could be in some situations.”
Dr. Peat listed studies for interest, including a study of the association between diet and esophageal cancer in Taiwan (1) explored the importance of dietary factors in the development of esophageal cancer.
The purpose was to evaluate the effects of several common dietary factors on the risk of squamous cell carcinoma of the esophagus in a Taiwanese population. The association between diet and esophageal cancer was examined over a 6-year period.
Consumption of preserved and overheated foods was found to be associated with increased risk of esophageal cancer, whereas intake of fresh fruits, vegetables, and tea was inversely associated with this risk. Men who consumed fermented bean products, salted food and preserved/pickled vegetables more thanonce a week after age 40 years had a 3.4-fold risk.
It was further found that these preserved foods were more strongly associated with esophageal cancer among men who consumed fruit less than once per day than those who consumed fruits one or more times per day. These results suggest that a high intake of preserved foods and overheated drinks might increase the risk of esophageal cancer, and intake of fruit, vegetables, and tea might be negatively associated with risk of esophageal cancer. The results also suggest that diet is an important factor in the development of esophageal cancer in Taiwan.
Another study of Chinese historical records from about 2,000 years ago (2) noted several unique epidemiological features and possible risk factors of esophageal cancer in the country. It has been hypothesized that the prevalence of esophageal cancer in high-risk areas of China may be associated with fermented and moldy foodstuffs, nitrosamines, deficiencies of molybdenum, nutritional deficiencies, specific living habits, and poor oral hygiene. Accordingly, comprehensive studies are being conducted in Lin County and other areas with elevated risk of this disease so that the possible function of fungi and nitrosamines in the carcinogenesis of esophageal cancer can be determined.
Association between soy foods and colorectal cancer incidence is evaluated in a School of Public Health, University of North Carolina at Chapel Hill study. (3) Seven case-control studies evaluated the association between soy intake and colon or colorectal cancer (2,008 cases). Point estimates generally suggest an inverse association between higher soy consumption and colon cancer onset, although nearly all of the confidence intervals overlap 1.0. Two of the nine case-control studies focused on adenomas as the outcome.
So, from what I understand, lactic acid actually puts stress on the liver. With all the toxins, with the pollution, with the stress, with low thyroid and high estrogen, the body just can’t deal with added lactic acid. A little bit of Kimchee may be fine, but, personally, I would rather eat ice cream!
1. J Gastroenterol Hepatol. 2004 Jun;19(6):632-7. Association between diet and esophageal cancer in Taiwan. Hung HC, Huang MC, Lee JM, Wu DC, Hsu HK, Wu MT. College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
2. Natl Cancer Inst Monogr. 1982;62:113-20. Epidemiology of esophageal cancer in China. Li JY.
3. Nutr Cancer. 2003;47(1):1-12. Soy consumption and colorectal cancer. Spector D, Anthony M, Alexander D, Arab L. School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.