Fermentation: turning foods into superfoods

Science by Dr. Ben Bikman

Modern conveniences are a blessing in most every way, but, oddly, refrigeration may have yielded unintended consequences on how we digest and ultimately metabolize the foods we eat. Before storing foods at 40F to prevent them from “going bad”, many foods and drinks were, deliberately or not, fermented. This process involves bacteria digesting the sugars (fructose, lactose, glucose, etc.) and producing myriad beneficial products (more on that below). Thus, the metabolic benefits of fermentation are as much a matter of what’s lost than what’s gained.

When bacteria are fermenting a food, like a grain or fruits, they eat the starches and sugars. Thus, by eating the starches in the fermenting food, the bacteria unwittingly help us by lowering the amount of starch we consume, thereby lowering the blood glucose and insulin effects of the foods. So, we have two pronounced insulin-sensitizing benefits when we consume a fermented food: we consume less starch than the non-fermented version; and, we ingest beneficial bacteria that can act as probiotics in our intestines.

Western diets include virtually no fermented foods, though some have remained, albeit sparingly (e.g., yogurt, sourdough bread, etc.). In contrast to the West, Eastern cuisine has maintained a healthier appreciation for fermented foods. Perhaps the most notable is kimchi, a mix of fermented vegetables. Sure enough, eating kimchi helps lower glucose and insulin levels in people with insulin resistance [1]. Interestingly, this study compared the effects of fresh kimchi against 10-day-old kimchi, suggesting that it wasn’t the vegetables that were important, but rather what had happened to them while fermenting. Similar benefits may be seen with fermented ginseng and soybeans [2].

But eating fermented foods isn’t the only way to benefit from the work of beneficial bacteria; probiotics may do the trick. Probiotics are bacteria you ingest that improve your health, usually in the form of a capsule or powder (if not part of a fermented food). Several lines of evidence support the insulin-sensitizing effects of probiotics and much of this is summed up in a meta-analysis that compiled the findings of 17 randomized trials, concluding that probiotics effectively lower fasting glucose and insulin[3] .



Fermentation and Fats

From an insulin perspective, the glucose-lowering effects of fermentation is the main benefit. But, as I mentioned above, there’s more to fermentation than just losing sugars; we also gain something. Bacteria are unique in what they produce after they eat glucose. One of the by-products are short-chain fatty acids. You may be surprised to learn what these small fats can do.

Firstly, these short fats (they’re literally much shorter than other fats we eat) have no capacity to be stored in the body–we must burn them. In fact, these fats demand to be burned so strongly that they stimulate the cell to help the burning; short-chain fats stimulate mitochondrial biogenesis (the place in the cell where we burn fat for fuel) [4].

Secondly, a result of this rapid fat burning is the production of ketones. These short fats aggressively produce ketones. This is one of the reasons why people focus on medium-chain fats, such as coconut oil, for producing ketones [5]. Short-chain fats do it even better.

Lastly, these fats also have the potential to help cells of the body become more insulin sensitive [6]!

Fermentation and Protein

Finally we come to protein–even protein is influenced by fermentation.

However, dietary protein also gets a boost, especially if it’s plant protein. An enormous problem with trying to get dietary protein from plant source is that the proteins are poorly digested and absorbed–you simply aren’t getting as much of the protein as you think you are [7], not to mention vitamins and minerals [8]. At least some of this compromised digestion is the result of “anti-nutrients” found within all plant proteins; molecules like trypsin inhibitors and tannins can block up to 50% of the digestion of proteins from sources like soy, wheat, pea, and more [9].

Fermentation directly addresses this concern by removing anti-nutrients, thereby improving protein digestion and absorption[10] !


Clearly, in all our advancements in food production and storage, the benefits of fermentation have been lost. In addition to possibly adding probiotics to your supplement regimen, focusing on fermented foods is a sure way to provide a metabolic boost you may be lacking.



  1.  An, S.Y., et al., Beneficial effects of fresh and fermented kimchi in prediabetic individuals. Ann Nutr Metab, 2013. 63(1-2): p. 111-9
  2.  Cheon, J.M., D.I. Kim, and K.S. Kim, Insulin sensitivity improvement of fermented Korean Red Ginseng (Panax ginseng) mediated by insulin resistance hallmarks in old-aged ob/ob mice. J Ginseng Res, 2015. 39(4): p. 331-7; Kwon, D.Y., et al., Long-term consumption of fermented soybean-derived Chungkookjang attenuates hepatic insulin resistance in 90% pancreatectomized diabetic rats. Horm Metab Res, 2007. 39(10): p. 752-7.
  3.  Ruan, Y., et al., Effect of Probiotics on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials. PLoS One, 2015. 10(7): p. e0132121
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4878196/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4878196/
  6. https://www.nature.com/articles/nrendo.2015.128
  7. https://pubmed.ncbi.nlm.nih.gov/24482589/
  8. https://pubmed.ncbi.nlm.nih.gov/34837522/
  9.  Sarwar Gilani, G., C. Wu Xiao, and K.A. Cockell, Impact of antinutritional factors in food proteins on the digestibility of protein and the bioavailability of amino acids and on protein quality. Br J Nutr, 2012. 108 Suppl 2: p. S315-32; Clemente, A., et al., Eliminating anti-nutritional plant food proteins: the case of seed protease inhibitors in pea. PLoS One, 2015. 10(8): p. e0134634.
  10. https://jabonline.in/abstract.php?article_id=575&sts=2

This article is for informational and educational purposes only. It is not, nor is it intended to be substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice.