CLA – Conjugated linoleic acid

One of the the most interesting dietary conundrums I’ve encountered. Basically, every study that has been done with it has shown some kind of positive effect – you could say it’s good “for everything”. On the other hand, it is found basically only in animal products; on a vegan diet it is practically absent. Paradoxically, vegans are less likely to contract the diseases it is supposed to prevent.

It’s called rumenic acid, as it’s found in very large amounts in the meat and milk of cows, mainly those that can pasture on free range; it’s almost absent in the bodies of industrially raised animals (that is, in almost every product available in the store). In fact, it’s a collective name for dozens of substances with slightly different properties, some of them belonging to the notorious “trans” fat group.

Perhaps the most hopeful is its anti-cancer effect. Without too much exaggeration, it can be said that mankind knows of few substances that are able to exert a stronger effect without side effects, or perhaps none at all. For example, in this study

https://jn.nutrition.org/content/129/12/2135.full

supplementation – whether from pills or enriched butter – reduced the risk of cancer twofold. Dozens of studies confirm its effects “in the test tube,” but unfortunately there are no solid clinical trials in humans – admittedly, there is an epidemiological study in which women with the highest concentrations had less than half the risk of the disease than those with the lowest

https://www.ncbi.nlm.nih.gov/pubmed/11525591

but too many factors come into play here. A person consuming CLA necessarily provided a number of other co-occurring substances along with it. It should be the first supplement a cancer victim reaches for – after all, what is he risking? Will he die from it more?

Conflicting results have been obtained with clinical trials on asthma, as in the well-known saying in my country, one rabbi says it works, another says just the opposite.

https://www.ncbi.nlm.nih.gov/pubmed/20642580

https://www.ncbi.nlm.nih.gov/pubmed/21411834

Perhaps it depends on whether the patients were overweight, it seems to work more effectively in them. Given that one study showed a strong effect in making it easier for patients to breathe, while in the other there was no effect (and therefore no harm), you can take a chance, especially if you have a few extra pounds.

And here we come to another very interesting point: this is a substance that can literally remodel the shape of the body. Fat disappears, muscles appear. Well, maybe I exaggerated a little, but only a little. The difference won’t be particularly big, just a few pounds a year, but it’s hard to find another substance that will show any change in body fat at all without side effects. Here CLA is unrivaled.

It’s not entirely clear what its effects on the human brain might be. In rats, supplementation during pregnancy significantly improved memory and reduced anxiety in offspring.

https://www.ncbi.nlm.nih.gov/pubmed/25913570

https://www.ncbi.nlm.nih.gov/pubmed/23916660

It is known that the substance affects brain function in some way, but in what way? This remains a mystery for the time being.

Supplementation increased the number of mitochondria and the ability of muscles to consume oxygen.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3515476/

At this point, anyone involved in endurance sports (cycling, running, swimming) should stop reading and run to the pharmacy. However, if they lasted a few seconds and read this paragraph to the end, it turns out that supplementation increases oxidative stress in muscles during prolonged exercise.

https://www.ncbi.nlm.nih.gov/pubmed/17313269

This can be counteracted with antioxidants, the question is whether the game is worth the candle. While taking this wonder, one can expect an increase in testosterone levels, which is practically always beneficial for athletes:

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0079686

In fact, one wonders if athletes on specific diets (vegans) will benefit from the additional supplementation, while the rest can give themselves the extra expense, as those eating an average diet had no visible positive effect.

https://journals.lww.com/nsca-jscr/Citation/2014/08000/Effects_of_6_Weeks_of_Aerobic_Exercise_Combined.7.aspx

All indications are that we have another substance that was supposed to help in theory, but did not work in practice.

Supplementation very significantly improved the health of patients with rheumatoid arthritis.

https://onlinelibrary.wiley.com/doi/10.1111/j.1756-185X.2009.01374.x/abstract

The mechanism at work here was the quieting of inflammation, from which it can be concluded – cautiously for the time being – that there will be similarly beneficial effects in other conditions of the autoimmune type or with a course of inflammation, and indeed, supplementation has quieted Crohn’s disease quite significantly.

https://www.ncbi.nlm.nih.gov/pubmed/22521469

It’s too early to write about its effect on the cardiovascular system – studies suggest it’s positive, but the results are quite contradictory.

It remains to look at the paradox of vegetarianism. Studying the concentration of these acids in the body, it was observed that vegetarians had significantly lower concentrations of the c9t11 isomer, while vegans had almost three times lower concentrations compared to omnivores. Slightly smaller – but also pronounced – were the differences for t10c12 (apologies to purists if I wrote in a different form than the one used in our nomenclature).

https://ajcn.nutrition.org/content/82/2/327.full

If CLA is so healthy, then theoretically vegans should clearly suffer more often from ailments that disappear after supplementation. Meanwhile, vegans have about a 15% lower risk of cancer (studies of this type generally take into account additional factors, i.e., for example, for non-smoking vegans are matched with non-smoking omnivores, I add this because soon some “wise” person will start proving that vegans probably live healthier in general, therefore they get sick less often). In general, vegans statistically live longer and get sick less often.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4073139/

The example of Japan provides even more food for thought. The people of this country, where there are virtually no sources of CLA in the diet, until recently still suffered from breast or prostate cancer 3 to 5 times less often than Western societies (this has changed with the increase in meat and dairy consumption, but they still have less than half the risk). What’s more, when such a Japanese man moves to the US and starts eating large amounts of the substance – he simultaneously increases his risk of getting the disease to that of his white neighbors. So one can confidently rule out “Japanese genes” as the cause of this low incidence. It is obvious that diet is involved. How does this relate to the research on CLA when, on the one hand, those with the highest concentrations in their blood suffer from these cancers less than half as often, and on the other hand, the Japanese who consume virtually none of it are so resistant to it?

Maybe it’s a matter of specific interplay of different elements, maybe CLA protects partially but not sufficiently against other harmful substances co-occurring in meat or milk, so a person consuming it from natural sources will paradoxically have worse health? Such a slightly more blunt example: antibiotics or chemotherapy are very harmful, but in some situations they can save lives. That is, if we eat some harmful bacteria and sip antibiotics, our health will be better than if we did not sip them, which does not mean that these drugs are “healthy.” This, by the way, is a favorite argument of various para-experts who read one study and lecture the scientists who have been working on the issue all their lives, for example, one online sect pastes everywhere a study in which the ketogenic diet improved the health of people dying of diabetes, which is supposedly “proof” that it is generally healthy and right for people.

Or is it all about the duration of action? Quite a few substances seem to help when we use them for a short time, but in the long run they cause degenerative changes, slow but inevitable. Maybe that’s why CLA has rapid positive effects in clinical trials, but on the other hand, people who consume it from diet, have much worse health?

I myself stopped eating meat about 20 years ago for ethical reasons, but the positive health effect I felt was so powerful that I stayed on the diet after growing out of that youthful idealism. Something is severely wrong here, on the one hand, health improves tremendously after weaning off sources of CLA, while on the other hand, dozens of studies show that it is beneficial.

I love to experiment on myself, so I started a trial supplementation. I keep a close eye on all my health parameters, since I’m an amateur athlete, I very often take basic measurements, such as orthostatic tests or measuring the relationship of performance to heart rate. Some things, such as a change in cancer risk, are not observable, but I think that if CLA has any clear health benefit, a vegetarian with 20 years of experience (a good portion of which as a vegan) should feel it.

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