Most people in the health blogosphere focus on the positives of kefir; it is the bee’s knees! However, what about the negatives of ingesting the probiotic drink? Why do so many of the clients I coach seem to be intolerant of the beverage? It is chocked full of strains of probiotic bacteria and yeast; it should help revitalize the digestive tract, yet is it truly the panacea that everyone praises?

What is Kefir?

Kefir is a fermented milk product that originated from the Caucasus mountain region. It is a slightly tangy beverage full of probiotic yeast and bacteria. It is made by adding kefir grains (a “grain” is a combination of bacteria, yeast, proteins, lipids, and carbohydrates) to a liquid medium (either ruminant dairy, coconut milk / water, or water). “Controlled” fermentation occurs to produce the actual kefir product. 1

Since kefir is a fermented beverage, it is rich in many different vitamins, minerals, SCFA’s, and amino acids. The fermented drink contains: 2 3 4 5 6

  • B vitamins (thiamin, folate, B-12, biotin)
  • Vitamin K2
  • Calcium
  • Magnesium
  • Phosphorus
  • Propionic acid
  • Acetate
  • Vitamin A
  • Vitamin E
  • Amino acids (methionine, cysteine, tryptophan, phenylalanine, tyrosine, isoleucine, threonine, lysine, valine)
  • Lactoferrin
  • Probiotic bacteria and yeast

Why I Am Hesitant In Recommending Kefir

Kefir has helped many people recover from their digestive woes and improve their overall health. That being said using it on a daily basis maybe hiding digestive issues if it brings constant relief. There are issues with its use including:

  • Histamine intolerance – some kefir contains strains that produce histamine. If you are suffering from histamine intolerance, then you want to stay away from kefir that contain: Lactobacillus bulgaricus, Lactobacillus casei, Lactobacillus helveticus, and Lactobacillus reuteri (might be ok for some people with histamine intolerance, converts histidine to histamine). 7 8 9
  • SIBO – I do not recommend the ingestion of probiotics when motility is compromised.
  • Yeast and aldehyde sensitivity – the yeast in the probiotic drink can produce aldehyde. Aldehydes are broken down in the body by the enzyme aldehyde dehydrogenase in the liver. The body’s production of aldehyde dehydrogenase depends on bio-availability of molybdenum, liver function, and genetics (ALDH genes). People with yeast sensitivities do not have enough aldehyde dehydrogenase and because of this react negatively to products containing yeast and mold. 10 11
  • D-lactate sensitivity – many of the lactic acid producing bacteria in kefir produce d-lactate. L-lactate is the primary lactic acid produced within the body and is readily metabolized. D-lactate is also produced by our bacteria and our metabolism, but in lesser amounts. When d-lactate is over produced and leaks out into the bloodstream from our gut, medical problems including delirium, ataxia, slurred speech, trouble concentration, and brain fog can occur. Though true d-lactate acidosis is rare (short bowel syndrome), issues from too much d-lactate being in the blood can occur. L. acidophilus, L. bulgaricus, L. fermentum, L. delbrueckii subsp lactis are examples of a d-lactate producing probiotics. 12 13 14 15 16 17
  • Contamination – production of fermented foods always comes at a likelihood of contamination. Granted the risk of contamination of a foreign strain is manageable in a controlled environment. Microorganisms, however, are mostly everywhere and are hard to keep out of a medium that is tailored to their growth.
  • Immunocompromisation – immunocompromised individuals should ingest probiotic foods or probiotic supplements with caution because of potential opportunistic effects.
  • Casein sensitivity – casein is a protein found in some dairy products (milk, cheese, kefir). Casein can be a hard to digest protein and can cause inflammation and digestive issues for some people. Casein also contains the opioid peptide casomorphin, which can slow motility and possibly cross the blood brain barrier causing proposed issues (cravings, histamine intolerance, further slowing of motility). There are claims of differing beta-casein proteins, known as A1 and A2. A1 proteins are mostly found in U.S. and Canadian dairy and may be more reactive in the gut because of the release of beta-casomorphin-7 upon its digestion. Also, A1 beta-casein contains histidine at position 67 of its makeup instead of proline that may affect its digestion and possible triggering in people who are histamine intolerance. However, studies are differing in the reactions of A1 or A2 casein in the human body. To be the most health conscious, if possible, I would consume milk or dairy products produced from A2 dairy. 18 19 20 21 22
  • Lactose intolerance – lactose is a disaccharide sugar found in some forms of dairy. Not all dairy kefir contains lactose. Some people are lactose intolerant and ingestion of the sugar causes digestive symptoms including diarrhea, abdominal cramps, gas, and bloating. 23
  • MAP (Mycobacterium avium paratuberculosis) – If you suffer from ulcerative colitis or Crohn’s disease you should avoid all dairy products including kefir produced from dairy. If you are suffering from either condition you should have little issue with dairy free kefir.

Final Thoughts on Kefir

Kefir is fine to ingest occasionally for most people as long as you do not have any of the above issues.

Homemade kefir might be a better option because you can control the strains used you use and the type of starter material (dairy, coconut, or water). It is possible to produce the fermented drink overlooking most of these issues from home. You could produce for example either water or coconut kefir from d-lactate free / low histamine producing probiotics and yeast. In doing so, you would avoid issues with d-lactate sensitivity, histamine intolerance, and casein / lactose intolerance. If I were to produce kefir at home, this is what I would make so that I could ingest the best possible kefir.24

What about producing kefir without using yeast? Well, kefir technically is supposed to have yeast in it, producing kefir without yeast is more akin to producing yogurt, sorry.

That being said if you were suffering from SIBO, yeast sensitivity, or severe immunocompromisation there might be no version of the drink that you would be able to tolerate. I cannot recommend kefir ingestion if you fall into these categories.

  1. http://chriskresser.com/kefir-the-not-quite-paleo-superfood/
  2. http://chriskresser.com/kefir-the-not-quite-paleo-superfood/
  3. http://jitek.ub.ac.id/index.php/jitek/article/view/157
  4. http://www.ncbi.nlm.nih.gov/pubmed/24532061
  5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC65674/
  6. http://users.sa.chariot.net.au/~dna/kefir-composition.htm
  7. http://thelowhistaminechef.com/these-probiotic-strains-lower-histamine-rather-than-raising-it/
  8. https://examine.com/supplements/lactobacillus-reuteri/
  9. https://www.bulletproofexec.com/why-yogurt-and-probiotics-make-you-fat-and-foggy/
  10. http://www.ncbi.nlm.nih.gov/pubmed/18983993http://www.jbc.org/content/227/1/533.full.pdf
  11. http://lpi.oregonstate.edu/mic/minerals/molybdenum
  12. http://www.biolab.co.uk/docs/dlactate.pdf
  13. http://www.hindawi.com/journals/grp/2015/476215/
  14. http://www.ncbi.nlm.nih.gov/pubmed/15987839
  15. http://www.mommypotamus.com/popular-probiotic-strain-may-induce-neurotoxicity/
  16. http://www.ncbi.nlm.nih.gov/pubmed/22968410
  17. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3723183/
  18. http://www.breakingtheviciouscycle.info/knowledge_base/detail/casein-sensitivity/
  19. http://www.marksdailyapple.com/dairy-intolerance/#axzz3wodQdDP3
  20. http://www.amymyersmd.com/2013/04/the-dangers-of-dairy/
  21. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwj19dKlv57KAhVMRSYKHXShBpAQFgguMAI&url=http%3A%2F%2Fblog.healthkismet.com%2Fcasomorphins-cheese-addiction-diet-health&usg=AFQjCNE3OyNj_9IbJzFAxLDbiJJBExHpzg&sig2=3uSj-Sf6yVdPZSS08Fm8GA
  22. http://www.nature.com/ejcn/journal/v59/n5/full/1602104a.html
  23. http://www.mayoclinic.org/diseases-conditions/lactose-intolerance/basics/definition/con-20027906
  24. https://www.jenreviews.com/kefir/
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