The Specific Carbohydrate Diet

Frequently Asked Questions

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D-lactic acid

27th Jan 2004 Elaine writes:
Since researching D-lactic acid, I have just received some enlightening news.

To begin with, my book talks much in the Brain Connection and in the Autism Connection chapters about the effect on behavior of too much D-lactic acid being absorbed into the bloodstream as a result of bacterial growth - even good guy bacteria sometimes. I thought that, usually, when D-lactic is produced, equal amounts of L-lactic acid is also produced and this is the form we need not be concerned about because L-lactic is quickly metabolized by the liver, does not accumulate in the bloodstream and, therefore, does not threaten the brain cells.

I found an authority on this, Dr Brian A. Nummer, Ph.D. and we have been dialoguing, here is my question to him and what he told me.

To Brian:
So you are telling me that the terminology "whey" can be used correctly to describe the watery separation as in curd and whey (no fermentation) (as is accomplished by rennin) and also can be used to describe the watery formation after yogurt production. So, both can aptly be called" whey?" And now that I have your ear, could you please tell me if the
lactic acid produced in making yogurt is D-lactic acid or L-lactic acid or is it a combination of both? Thanks so much.

To Elaine:
Yes, whey is used for the water phase after coagulation of milk casein regardless of method. Whether D- or L- lactic acid is produced will depend on the strains of lactic acid bacteria. Since the actual yogurt culture can vary there is no simple answer. You would have to look at the members of the culture used. Lactobacillus bulgaricus, L. helveticus, and L. delbrueckii will produce optically pure (99%) L+. If my memory serves correctly Streptococcus thermophilus will also produce only L+.

Dr Brian A. Nummer, Ph.D.
Project Coordinator
National Center for Home Food Preservation

Elaine's comment:
This means that using Lactobacillus Bulgarians and Streptococcus thermopiles in making our yogurt, we are home safe as far as D-lactic acid is concerned.

I am going to pursue this further and will let you know what I find out. In addition, I must find out if this is so for Lactobacillus acidophilus and some of the other probiotic strains that people take in addition to yogurt.

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