6

votes

Does lactic acid from fermented foods and beverages have negative effects on the human body as Ray Peat suggests?

Answered on September 12, 2014
Created December 19, 2011 at 11:28 PM

Recently I read an article by Ray Peat describing the almost limitless negative effects of lactic acid on the human body: http://raypeat.com/articles/aging/altitude-mortality.shtml

Peat does not consume any fermented foods except cheese for this reason. Although he provides tons of references supporting his statements about lactic acid in the human body and it all makes sense to me, I have two problems with his recommendation to avoid all fermented foods except cheese: 1 - just about every single culture throughout the recorded history of humanity (HG or agrarian) has consumed at least one fermented food or beverage in their diet, including the longest living cultures like the Okinawans; 2 - I recently started making water kefir and although I have not noticed any significant effects on my health from it yet, I really don't want to give it up because of how cheap and superior in both quantity and variety of species it is compared to probiotic supplements.

Can someone reconcile the negative effects of lactic acid described in the above article by Peat with the known health benefits of consuming fermented foods and beverages daily? Could there be some property of the fermented foods and beverages that offsets the putative negative effects of the lactic acid? Is this a perfect example of the limitations of science in explaining human health and disease or is there validity to Peat's argument? Any facts or ideas about this subject will be greatly appreciated.

If anyone has any evidence showing positive effects of lactic acid on the body I would be interested in that also.

Abf0b6d5e20906f742fd600887292c15

(192)

on February 24, 2013
at 03:40 AM

It could just be that they are good at preserving food. Okinawa being a tropical island foods would spoil rapidly if they weren't preserved through fermentation and other methods

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 23, 2011
at 10:49 PM

Your statement about the history of fermented foods compared to neolithic foods is a point well taken, however it doesn't explain the fact that all of the longest lived cultures I have read about (Hunzas, Bulgarians, Okinawans, etc.) consume at least one fermented food or beverage regularly. To the contrary, cultures that consume the most neolithic foods (like the U.S.) have shortened lifespan and/or greater incidence of disease. Correlation does prove causation, but I can't believe the correlation between fermented food/beverage consumption and health and longevity is a coincidence.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on December 23, 2011
at 02:53 PM

I thought you did the paleo diet jon?? People have been eating grains, legumes and other neolithic foods just as long as fermented foods. Maybe it wasn't weeded out because it produces alcohol and new food taste? Your examples aren't that great, people have been eating human flesh since the beginning of humans, should you become a cannibal?

Cf32992bfa1907147c7cdc451bba9c63

(2890)

on December 22, 2011
at 08:38 PM

Very interesting no doubt, but if anything it reinforces the significance of glucose as fuel.

Cf32992bfa1907147c7cdc451bba9c63

(2890)

on December 22, 2011
at 08:37 PM

Jon, if you re-read the wikipedia article I think you will see that it states the lactate comes from glucose. Then, intercellular lactate shuttle transfers lactate molecules to neurons. So glucose still is the fuel source, it is just turned into lactate by other brain cells for the neurons.

Cf32992bfa1907147c7cdc451bba9c63

(2890)

on December 22, 2011
at 08:37 PM

Jon, if you re-read the wikipedia article I think you will see that it clearly states the lactate comes from glucose. Then, intercellular lactate shuttle transfers lactate energy to neurons. So glucose still is the fuel source, it is just turned into lactate by other brain cells *for* the neurons.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 08:25 PM

This is in addition to the use of lactic acid in the Cori cycle of course.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 08:24 PM

Just found evidence to support both of your statements: http://en.wikipedia.org/wiki/Lactic_acid#Brain_metabolism Apparently Peat isn't aware of this information or is discounting it for some reason, although he must be aware of it since I found it using google and Wikipedia. I had no idea lactic acid had such an important role in the brain. Apparently this is one more strike against the allopathic/conventional medicine belief that glucose is the preferred or only fuel for the brain.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 08:18 PM

@cliff, from my research on this subject Peat is only partially correct, because brain lactic acidosis is only a symptom of the underlying dysfunction of brain ischemia. No ischemia, no lactic acidosis, a fact that makes the study you cited irrelevant IMO. Also, I wonder what Peat (or you) think about this info on lactic acid metabolism by glial cells in the brain: http://en.wikipedia.org/wiki/Lactic_acid#Brain_metabolism It seems Peat isn't aware of the role of lactic acid as an energy source for neurons.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 07:32 PM

Exactly my thoughts. Could a behavior that has survived so long throughout human history in almost every culture have harmful effects on health? I think such behaviors are necessarily weeded out of human culture over time, like eating poisonous mushrooms or the like. There had to be at least one good reason human cultures have continued to consume fermented foods and beverages so long.

Db4ad76f6f307a6f577e175710049172

(2297)

on December 22, 2011
at 12:45 PM

But, if traditional cultures often ate fermented foods long enough, you could argue that there would be selective pressure to select for a tolerance to lactic acid ingestion.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 09:30 AM

Thanks for the helpful advice, but if the kefir still has a strong fruit flavor when you taste it, doesn't that mean there is still a significant amount of sugar in it? From what I read there should be as little sugar as possible left in the kefir when you drink it, for the health of the grains and us.

Bb2adc4df725b56e99e0652c0feb4640

(254)

on December 22, 2011
at 06:05 AM

Well, they might not have known the details, but they likely would have noticed that "Hey, I'm not as hungry as I usually am!" It might have made a difference in lean times. This link suggests that kefir can have upto 3% alcohol. http://www.kefir.biz/ferm.htm

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 22, 2011
at 04:38 AM

@Jon, you can also use whole fruit of course, and I use lemon, raisins and a fig in my first fermentation, but when I've used whole fruit in the second fermentation the flavor isn't as strong and clear as when I use organic juice. I ferment the kefir/juice mix for a day on the counter and 2 days in the fridge and it seems just right (up north it might take a little longer to eat up the sugar.)

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 22, 2011
at 04:35 AM

For water kefir fermentation, you can use juice rather than whole fruit because the microbes eat the sugar. I do buy organic, though. For my blueberry batch, I used a juice mix that listed blueberry first but also included apple. At first, the blueberry was subdued but after fermentation the blueberry was the dominant flavor. I don't put juice in with the grains; it's added after the fresh water kefir is strained. The only fruit I know of that is avoided is grapefruit because it's something of a natural antibiotic and could kill some or all of the microbes.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 04:02 AM

I think one of primary benefits of the good bacteria in fermented foods/beverages is keeping the potentially pathological bacteria under control in the intestines, but studies like the ones cited above suggest there are many more benefits to regular consumption of LAB.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 03:58 AM

I never thought of that and it makes sense although before the advent of modern science such cultures would not have known that the lactic acid in fermented foods/beverages could reduce metabolic rate, which I am still not completely convinced of anyway. Now I want to know how long a food or beverage has to ferment to produce a significant amount of alcohol. From experience making water kefir, the longer I let it ferment the more acidic it becomes, so perhaps you are referring to other fermented foods or beverages like kombucha which is known for its higher alcohol content?

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 22, 2011
at 12:31 AM

Agreed! I'd expand that to meat as well. The natural "partner" that works for me is fruit and, since I make extra-fat yogurt it feels like a balanced meal.

Bb2adc4df725b56e99e0652c0feb4640

(254)

on December 22, 2011
at 12:16 AM

@jon is it beneficial or simply the lesser of two evils, by acting as a defense against nastier bugs.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 20, 2011
at 09:27 AM

+1 for the research showing the benefits of LAB. It doesn't seem logical that lactic acid could be harmful to humans when the bacteria that produce it are so beneficial.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 20, 2011
at 09:24 AM

Nance, I am really jealous of you for that. Unless you only used 1 blueberry I can't make that flavor of water kefir because blueberries are too expensive at my local grocery stores. Could cheap fruits like apples be used instead, or do certain fruits not work well with water kefir?

100fd85230060e754fc13394eee6d6f1

(18706)

on December 20, 2011
at 05:22 AM

I don't consider a stringing together of sentences that occasionally contain the word lactate an "argument".

100fd85230060e754fc13394eee6d6f1

(18706)

on December 20, 2011
at 05:10 AM

I was thinking something similar. Has he not heard of the Cori cycle?

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 20, 2011
at 04:36 AM

@Jon, as I read your question I'm sitting here sipping on a fizzy bottle of blueberry water kefir. :-))

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4 Answers

7
Cf32992bfa1907147c7cdc451bba9c63

on December 20, 2011
at 03:58 AM

Yeah lactic acid is a primary energy source so I dunno what he's smoking. It's like someone saying pyruvate is toxic.

100fd85230060e754fc13394eee6d6f1

(18706)

on December 20, 2011
at 05:10 AM

I was thinking something similar. Has he not heard of the Cori cycle?

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 08:25 PM

This is in addition to the use of lactic acid in the Cori cycle of course.

Cf32992bfa1907147c7cdc451bba9c63

(2890)

on December 22, 2011
at 08:37 PM

Jon, if you re-read the wikipedia article I think you will see that it clearly states the lactate comes from glucose. Then, intercellular lactate shuttle transfers lactate energy to neurons. So glucose still is the fuel source, it is just turned into lactate by other brain cells *for* the neurons.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 08:24 PM

Just found evidence to support both of your statements: http://en.wikipedia.org/wiki/Lactic_acid#Brain_metabolism Apparently Peat isn't aware of this information or is discounting it for some reason, although he must be aware of it since I found it using google and Wikipedia. I had no idea lactic acid had such an important role in the brain. Apparently this is one more strike against the allopathic/conventional medicine belief that glucose is the preferred or only fuel for the brain.

Cf32992bfa1907147c7cdc451bba9c63

(2890)

on December 22, 2011
at 08:38 PM

Very interesting no doubt, but if anything it reinforces the significance of glucose as fuel.

Cf32992bfa1907147c7cdc451bba9c63

(2890)

on December 22, 2011
at 08:37 PM

Jon, if you re-read the wikipedia article I think you will see that it states the lactate comes from glucose. Then, intercellular lactate shuttle transfers lactate molecules to neurons. So glucose still is the fuel source, it is just turned into lactate by other brain cells for the neurons.

5
96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 20, 2011
at 04:51 AM

Jon, the links below refer to research conducted in animals but they're probably relevant to why we seem to benefit from water kefir, yogurt, etc. And I think we need to distinguish between lactic acid and probiotic lactic acid bacteria.

In one study, probiotic lactic acid bacteria inhibited growth of Salmonella in young chickens.

In another, perhaps more relevant, I found this quote:

"Lactic acid bacteria also inhibit the growth of harmful putrefactive microorganisms through other metabolic products such as hydrogen peroxide, carbon dioxide and diacetyl."

A third document says, "Probiotic micro-organisms including lactic acid bacteria (LAB) positively influence the composition of the gut microflora; they stimulate the production of secretory IgA; they affect the targeted transportation of the luminal antigens to Peyer???s patches and they increase the production of IFN-??. LAB stimulate the activity of non-specific and specific immune cells. ???ese properties of the LAB depend on the particular species or strain of bacteria. ???ese singularities are probably determined by differences in the cell wall composition. LAB belong to a group of beneficially acting bacteria and they are able to eliminate damage to the gut microenvironment; they stimulate local and systemic immune responses and they maintain the integrity of the gut wall."

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 20, 2011
at 09:27 AM

+1 for the research showing the benefits of LAB. It doesn't seem logical that lactic acid could be harmful to humans when the bacteria that produce it are so beneficial.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 04:02 AM

I think one of primary benefits of the good bacteria in fermented foods/beverages is keeping the potentially pathological bacteria under control in the intestines, but studies like the ones cited above suggest there are many more benefits to regular consumption of LAB.

Bb2adc4df725b56e99e0652c0feb4640

(254)

on December 22, 2011
at 12:16 AM

@jon is it beneficial or simply the lesser of two evils, by acting as a defense against nastier bugs.

3
E5c7f14800c5992831f5c70fa746dc5c

(12857)

on December 22, 2011
at 12:29 PM

His recommendations are more about not burning glucose in a oxygen deprived state which produces lactic acid, this is where most of the damage from lactic acid occurs.

People get pretty hyped on the fermented food thing because traditional cultures did it but they forget they did it because it was a necessity they would die without. Would they be healthier with out it?? Maybe, maybe not. Not a very good argument though imo.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3043458/ "Cerebral lactic acid, a product of ischemic anaerobic glycolysis, may directly contribute to ischemic brain damage in vivo."

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 08:18 PM

@cliff, from my research on this subject Peat is only partially correct, because brain lactic acidosis is only a symptom of the underlying dysfunction of brain ischemia. No ischemia, no lactic acidosis, a fact that makes the study you cited irrelevant IMO. Also, I wonder what Peat (or you) think about this info on lactic acid metabolism by glial cells in the brain: http://en.wikipedia.org/wiki/Lactic_acid#Brain_metabolism It seems Peat isn't aware of the role of lactic acid as an energy source for neurons.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 07:32 PM

Exactly my thoughts. Could a behavior that has survived so long throughout human history in almost every culture have harmful effects on health? I think such behaviors are necessarily weeded out of human culture over time, like eating poisonous mushrooms or the like. There had to be at least one good reason human cultures have continued to consume fermented foods and beverages so long.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on December 23, 2011
at 02:53 PM

I thought you did the paleo diet jon?? People have been eating grains, legumes and other neolithic foods just as long as fermented foods. Maybe it wasn't weeded out because it produces alcohol and new food taste? Your examples aren't that great, people have been eating human flesh since the beginning of humans, should you become a cannibal?

Db4ad76f6f307a6f577e175710049172

(2297)

on December 22, 2011
at 12:45 PM

But, if traditional cultures often ate fermented foods long enough, you could argue that there would be selective pressure to select for a tolerance to lactic acid ingestion.

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 23, 2011
at 10:49 PM

Your statement about the history of fermented foods compared to neolithic foods is a point well taken, however it doesn't explain the fact that all of the longest lived cultures I have read about (Hunzas, Bulgarians, Okinawans, etc.) consume at least one fermented food or beverage regularly. To the contrary, cultures that consume the most neolithic foods (like the U.S.) have shortened lifespan and/or greater incidence of disease. Correlation does prove causation, but I can't believe the correlation between fermented food/beverage consumption and health and longevity is a coincidence.

Abf0b6d5e20906f742fd600887292c15

(192)

on February 24, 2013
at 03:40 AM

It could just be that they are good at preserving food. Okinawa being a tropical island foods would spoil rapidly if they weren't preserved through fermentation and other methods

3
Bb2adc4df725b56e99e0652c0feb4640

(254)

on December 22, 2011
at 12:20 AM

It is possible that cultures used it as a mechanism to reduce metabolism in order to make do with less food and less nutrition. Another confounder is the fact that continuing the fermentation will make alcohol, that is pretty sought after.

On a personal note, it feels wrong to eat yogurt and eggs at the same meal.

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 22, 2011
at 12:31 AM

Agreed! I'd expand that to meat as well. The natural "partner" that works for me is fruit and, since I make extra-fat yogurt it feels like a balanced meal.

Bb2adc4df725b56e99e0652c0feb4640

(254)

on December 22, 2011
at 06:05 AM

Well, they might not have known the details, but they likely would have noticed that "Hey, I'm not as hungry as I usually am!" It might have made a difference in lean times. This link suggests that kefir can have upto 3% alcohol. http://www.kefir.biz/ferm.htm

6cca02352c216b4ca8325fda7d83832c

(1042)

on December 22, 2011
at 03:58 AM

I never thought of that and it makes sense although before the advent of modern science such cultures would not have known that the lactic acid in fermented foods/beverages could reduce metabolic rate, which I am still not completely convinced of anyway. Now I want to know how long a food or beverage has to ferment to produce a significant amount of alcohol. From experience making water kefir, the longer I let it ferment the more acidic it becomes, so perhaps you are referring to other fermented foods or beverages like kombucha which is known for its higher alcohol content?

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