Molecule in meat may increase heart disease risk

[aLptHW4k4y]

http://www.sciencenews.org/view/generic/id/349480/description/Molecule_in_meat_may_increase_heart_disease_risk_

This is somewhat alarming. Bacteria found specifically in meat-eaters metabolize L-carnitine into some nasty, artery-hardening compound.
I can't think of a reason that raw meat eaters would be immune to this, maybe some further research on the specific bacteria will give insight into that.

[LePatron7]

If you want a healthier gut microbe environment, consider raw-scd

[TylerDurden]

Heart-disease is directly linked to the consumption of heat-created toxins such as advanced glycation end products,
http://www.ncbi.nlm.nih.gov/pubmed/18473849

 so raw-meat-eaters do not have to worry.

[cherimoya_kid]

I wonder if raw meat is processed into TMAO.  I also wonder that, if it does,  if blood levels of TMAO are as high after eating meat raw instead of cooked.

[CitrusHigh]

http://www.sciencenews.org/view/generic/id/349480/description/Molecule_in_meat_may_increase_heart_disease_risk_
I can't think of a reason that raw meat eaters would be immune to this, maybe some further research on the specific bacteria will give insight into that.

You cant think of any reasons? This study was done on cooked and processed meats, how does that apply at all to raw meat at all? We know how heating and processing warps food molecules, is it surprising that a toxic food results in toxic byproducts?

Staying with the big picture reminds us that yes, raw meat is our most biologically appropriate food.

[aLptHW4k4y]

I'm just saying that we can't simply exclude the possibility of these bacteria producing TMAO when eating raw meat, because there's no evidence regarding this. L-carnitine is a molecule that should be same in cooked as well as in raw meat.. it's not some sort of new compound created specifically from heating. If a lot of it is regularly coming from diet it makes sense that the number of gut bacteria that thrives on it will be high (hence the difference between meat eaters and vegans in that study). Here are the amounts in some foods

http://en.wikipedia.org/wiki/Carnitine#Food

[TylerDurden]

I'm just saying that we can't simply exclude the possibility of these bacteria producing TMAO when eating raw meat, because there's no evidence regarding this. L-carnitine is a molecule that should be same in cooked as well as in raw meat.. it's not some sort of new compound created specifically from heating. If a lot of it is regularly coming from diet it makes sense that the number of gut bacteria that thrives on it will be high (hence the difference between meat eaters and vegans in that study). Here are the amounts in some foods

http://en.wikipedia.org/wiki/Carnitine#Food

The whole point Thoth was making was that the L-Carnitine is altered by the heat from cooking, much as proteins etc. are also altered by that process.

[aLptHW4k4y]

The whole point Thoth was making was that the L-Carnitine is altered by the heat from cooking, much as proteins etc. are also altered by that process.

And you have a reference for this claim?

[TylerDurden]

And you have a reference for this claim?

  I already provided a scientific reference earlier in the thread pointing out that heat-created toxins derived from cooking(advanced glycation end products) are the real culprits behind heart-disease. Lowering such levels thereof reduces heart-disease, increasing levels thereof  aggravates heart-disease and increases the chance of it occurring.

Other than that, it is common-sense to assume that heat changes all substances in some way - after all, if heat is applied in  sufficient quantity and for long enough, all food turns into charcoal. There is already plenty of evidence showing that even slight cooking denatures proteins and lowers levels of vitamins etc., so, really, the onus is on you to find a study that confirms that l-carnitine is somehow magically protected against being altered by heat.

[ys]

This is just another correlation that probably does not mean anything just like countless other correlations. 

[aLptHW4k4y]

Not really, e.g. they gave l-carnitine to mice and they ended up with atherosclerotic plaque unlike controls, or mice given both l-carnitine and antibiotics. The research looks like it was very well done, leaving little room for remarks like "it's just a meaningless correlation".

Pure carnitine is not produced by heat but by other means (chemical processes, bacterial fermentation, etc.), resulting in really exactly these molecules, so we can't simply say it's different from l-carnitine in raw meat, nor can we blame the results on heated/processed food (except maybe for the human trials between vegans and omnivores who were given meat I think).

[Projectile Vomit]

I agree with aLptHW4k4y that the study is fairly well done and leaves little room for questioning the link between L-carnitine and the potential for TMAO production in the presence of the right gut bacteria.

One worthwhile question though is whether the assumption that the gut bacteria that turn L-carnitine into TMAO would be as abundant in a healthy person's gut as the study assumes. The study compares vegans, vegetarians and people who assumedly eat a standard, industrial-food diet. None of these groups necessarily have healthy gut flora, and all would have very different gut ecologies relative to someone who's been eating a raw food diet, particularly one that's light on starch. 

An interesting study nonetheless, and I'm glad it was posted here.

[aLptHW4k4y]

That's what I'm hoping for, that the gut of someone eating raw does not allow much growth of such bacteria, but it's a bit far-fetched idea. Especially since these bacteria grow very easily once l-carnitine increases in the diet (at least in the mice). Or another (far-fetched) idea is that our systems have better capacity to get rid of the TMAO. Anyway, I'm sure a lot more research will follow on this so we can continue talking with less speculation.

[TylerDurden]

The point is that artificially-produced l-carnitine is even stranger in form than l-carnitine as found in cooked foods, let alone l-carnitine found in raw foods. So, it is the equivalent of  ridiculously stating that since ascorbic acid has the same chemical formula as vitamin C, that it is the same as vitamin C. Such a statement would be considered absurd by any logical person as we all know that there are a multitude of other bioactive aspects, such as enzymes etc., which confound the issue.

[PaleoPhil]

Dave Asprey responded to the study and made a point that rawists should appreciate:

A) The researchers presumably measured effects of CAFO (Concentrated Animal Feeding Operations) industrial meat with antibiotics known to impact gut bacteria, NOT grass-fed or even just antibiotic-free meat, and didn’t test for the presence of antibiotics.

B) The researchers used cooking methods proven to create nitrosamines, which are precursors to TMAO (searing at high heat, George Forman style, is not Bulletproof).

C) The researchers failed to acknowledge that TMAO is a byproduct of digestion of a lot of things including vegetables and choline found in vegetable oils.

D) False basic assumptions about what causes heart disease (based on longstanding cholesterol propaganda) led to a misinformed analysis and conclusions of data.

...

The article explicitly states, “The researcher himself bought a George Foreman grill for the occasion, and the nurse assisting him did the cooking.” The researchers didn’t think outside the scientific box. Searing as a cooking method creates more of a known carcinogen – nitrosamine! Nitrosamines are methylated by bacteria in the gut, which forms a substance called dimethylnitrosamine, which is a very toxic breakdown product of TMAO, the very substance the scientists were investigating. Did the paper measure the presence of nitrosamines in the meat after cooking, or test whether the inflammatory effects of it were at fault? Nope… but they did show that the straight carnitine has an effect on TMAO levels in people with some kinds of gut bacteria, so at least some of the cause is not from the overcooked/burned meat.

http://www.bulletproofexec.com/the-red-meat-scapegoat-the-new-york-times-carnitine-heart-disease-and-science/

Chris Masterjohn is also going to respond to the study and he tends to be relatively raw-friendly, so that may prove interesting.

[cherimoya_kid]

I rarely eat meat, maybe once or a month or so, so it doesn't really make much difference to me.  I eat fish for my flesh foods.

But I really doubt that raw grassfed meat in moderation is a big cause of heart disease. 

[ys]

Not really, e.g. they gave l-carnitine to mice and they ended up with atherosclerotic plaque unlike controls, or mice given both l-carnitine and antibiotics.

That means that diet containing l-carnitine is not a staple for mice.  Mice usually subsist on grains, insects, and other scrap.  Red meat is hardly ever on their menu.

Just like they fed rabbits with diet cholesterol and they developed plaque.  Everyone knows cholesterol is not rabbits natural diet.

So I totally do not buy mice example.

[TylerDurden]

Thanks, PP, you put the nail in the coffin of this notion...

[Busgrw]

Just in case anyone is interested:

http://www.marksdailyapple.com/does-red-meat-clog-your-arteries-after-all/#axzz2Q5h4T9zD

[aLptHW4k4y]

Thanks PaleoPhil!

[van]

Gosh did I laugh hard when Mark wrote, that somehow the vegans got the steak down'.  Can you imagine the whole sequence....

[PaleoPhil]

Glad to be of assistance, Tyler and aLptHW4k4y. I'll take it a step further and burn the coffin with this:

There is boatloads of research suggestive of carnitine as a beneficial nutrient (see The Carnitine Miracle by Robert Crayhon) and red meat as a beneficial food (http://www.ncbi.nlm.nih.gov/pubmed/10426698d - women who ate more red meat had lower rates of heart disease). Carnitine is required to transport fatty acids to the mitochondria for the breakdown of fats to generate metabolic energy. Heck, plenty of people even take carnitine capsules as a healthy supplement. Why would such a crucial part of our natural functioning be highly toxic and why would any raw Paleo dieter who thinks there may be a problem with cooked red meat suspect carnitine as the main culprit instead of say nitrosamines or AGEs, based on this and other studies?

Foods rich in boron--"almonds, walnuts, avocados, broccoli, potatoes, pears, prunes, honey, oranges, onions, chick peas, carrots, beans, bananas, red grapes, red apples and raisins" (http://www.livestrong.com/article/242015-foods-high-in-boron-vitamins/#ixzz2Q1oG7zuM)--also promote carnitine production:

"Throughout an experimental period of 28 days, the mineral boron decreased leptin, insulin, and glucose levels, while increasing levels of both T3 hormone and carnitine in the blood." http://hairevo.com/shop/content/16-what-is-fruitex-b-calcium-fructoborate

Does this mean that those who take the carnitine/tmao study seriously are going to minimize or stop eating these foods too?

And this from the link that Busgrw shared is quite interesting:

TMAO itself may not be “all bad.” It’s an osmolyte – a protein stabilizer. It’s even been used to prevent cataract formation in mammalian eye lenses.
Read more: http://www.marksdailyapple.com/does-red-meat-clog-your-arteries-after-all/#ixzz2Q6gDLfWY

And there's this from a study that Mark Sisson lined to: "Of 46 different foods investigated, only fish and other sea-products gave rise to significant increases in urinary trimethylamine and N-oxide [TMAO]." So if this study is any indication, then for anyone who is concerned about TMAO from animal foods, it looks like fish would be the prime concern, rather than red meat.

Of course, someone can probably come up with some other study that exonerates fish and turns the implication back onto red meat or whatever other food they fear. I try not to get too hyped up about any single study. As Tyler and others have pointed out, something like 80% or more that were analyzed by an objective third party were found to be wrong.

[Projectile Vomit]

There is boatloads of research suggestive of carnitine as a beneficial nutrient (see The Carnitine Miracle by Robert Crayhon) and red meat as a beneficial food (http://www.ncbi.nlm.nih.gov/pubmed/10426698d - women who ate more red meat had lower rates of heart disease). Carnitine is required to transport fatty acids to the mitochondria for the breakdown of fats to generate metabolic energy. Heck, plenty of people even take carnitine capsules as a healthy supplement. Why would such a crucial part of our natural functioning be highly toxic and why would any raw Paleo dieter who thinks there may be a problem with cooked red meat suspect carnitine as the main culprit instead of say nitrosamines or AGEs, based on this and other studies?

Hi Phil, I can't get the link in the above paragraph to work. Is it correct?

[aLptHW4k4y]

Remove the d at the end, this works: www.ncbi.nlm.nih.gov/pubmed/10426698

[aLptHW4k4y]

Hah, and few days later something contradicting appears
L-Carnitine Significantly Improves Patient Outcomes Following Heart Attack

These findings may seem to contradict those reported in a study published earlier this month in Nature Medicine by Robert A. Koeth and others (link below), which demonstrated that metabolism by intestinal microbiota of dietary L-carnitine produced trimethylamine N-oxide (TMAO) and accelerated atherosclerosis in mice. They also noted that omnivorous human subjects produced more TMAO than did vegans or vegetarians following ingestion of L-carnitine, and suggested a possible direct link between L-carnitine, gut bacteria, TMAO, and atherosclerosis and risk of ischemic heart disease.

"The Nature Medicine paper is of interest," agrees senior investigator Carl J. Lavie, M.D.,FACC,FACP,FCCP, Medical Director of the Cardiac Rehabilitation and Prevention Center at the John Ochsner Heart and Vascular Institute at the University of Queensland School of Medicine in New Orleans, "but the main study reported there was in animals, and unlike our study, lacks hard outcomes." He also notes that "there are various forms of 'carnitine' and our relatively large meta-analysis specifically tested L-carnitine on hard outcomes in humans who had already experienced acute myocardial infarction."