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New research blaming L-carnitine

mellster

Marco
Messages
805
Location
San Francisco
From: http://news.yahoo.com/culprit-red-meat-linked-heart-disease-122309519.html

The high amounts of saturated fat and cholesterol in red meat have long been blamed for increasing people's risk of heart disease. But now, new research points a finger at another culprit in meat that may be more closely tied to this leading killer.
A new study reveals that a nutrient called l-carnitine, which is found in red meat and is also popular as a dietary supplement, may also play a role in the development of heart disease.
In a series of experiments in people and mice, scientists for the first time demonstrated that carnitine from foods as well as from supplements influenced cardiovascular risk.
"We now have an understanding of a new nutritional pathway that helps explain the long-standing recognition of a link between red meat and the development of heart disease," said study researcher Dr. Stanley Hazen, section head of preventive cardiology at the Cleveland Clinic in Cleveland, Ohio. The pathway involves the gut bacteria that metabolize carnitine in people who regularly eat meat, he said.
Hazen and his research team suspected there must be something else in red meat, besides its cholesterol and saturated fat, that explains its association with heart disease. "This study suggests carnitine may be a piece of this link," he said.
The findings were published online today (April 7) in the journal Nature Medicine.
A carnitine connection
Two years ago, Hazen and his research team discovered that microorganisms in the intestines can convert substances found in choline, a common dietary fat, to a by-product known as TMAO, trimethylamine-N-oxide.
This new study looked at l-carnitine, which has a similar chemical structure to choline.
Carnitine is a nutrient found at high levels in red meat, but fish, poultry, milk and other dairy products are also good food sources of it. Carnitine is also a popular over-the-counter diet supplement, often billed as helping to boost energy and bulk up muscle. It's found in some energy drinks and muscle milks.
The researchers looked at fasting levelsof blood carnitine in nearly 2,600 men and women. The findings showed that carnitine levels could quite strongly predict participant's risk of existing coronary artery disease, as well as the risk of having a major cardiac event, such as heart attack, stroke, or death over a three-year period, but only in adults who had high blood levels of TMAO.
Hazen's group also compared mice fed their normal chow, which is basically a vegetarian diet, with mice whose food was supplemented with carnitine.
"We saw that carnitine supplements doubled the rates of atherosclerosis in the mice," Hazen said. It did this by dramatically increasing levels of TMAO, which is produced by gut bacteria that metabolize l-carnitine.
As for how carnitine in red meat may be linked with heart disease, Hazen explained that chronic ingestion of carnitine fundamentally shifts the metabolism of cholesterol. "It's changing it in a way that will make you more prone to heart disease," he said. Eating carnitine causes more cholesterol to be deposited onto artery walls, and less to be eliminated from the body.
What to do
Besides looking at animal models, researchers also looked at what happens when people eat carnitine, comparing 51 people who normally eat meat to 23 people who were vegetarian or vegan (who consume no animal products). The researchers found that adults who avoid meat and eat fewer animal products produced much lower concentrations of TMAO in the blood compared with the meat eaters.
"If you're eating a lot of red meat, this study argues to consider cutting back," Hazen said. He recommended decreasing the frequency of eating red meat, and its portion size.
For people taking carnitine supplements, Hazen said he's unaware of a compelling study that shows a dramatic benefit from them. And taking the supplement could be influencing a person's long-term risk of heart disease, he suggested.
 

perchance dreamer

Senior Member
Messages
1,691
Hmmm, it doesn't look like Hazen made any distinctions in how the different forms of carnitine supplements affect the heart. GPLC, propionyl ester of carnitine with glycine, is supposed to be good for the heart by improving arterial blood flow.
 

adreno

PR activist
Messages
4,841
Well, this is a bit worrisome. And GPLC is still a source of carnitine, even though it's bound to glycine.

Carnitine is quite popular as a supplement for ME/CFS. Maybe it's time to reevaluate that.
 

perchance dreamer

Senior Member
Messages
1,691
Here's Steven Sinatra's reaction to this latest research on carnitine. He's an integrative cardiologist, who recommends carnitine as part of the Awesome Foursome for heart health supplements.

http://www.drsinatra.com/l-carnitine-is-not-only-safe-its-essential

He does sell supplements, but I don't think that negates the research he's done into supplements for heart health. I appreciate doctors who take an integrative approach. I first came across him in the Earthing book that came with my 1/2 sheet.

I think this is an interesting topic and I want to remain open minded, but the research presented by Hazen and the rest doesn't make me want to stop carnitine right now.
 

MeSci

ME/CFS since 1995; activity level 6?
Messages
8,231
Location
Cornwall, UK
Considering the length of time for which the blame has been placed on saturated fat (which an increasing number of scientists are now doubting), let's also bear in mind the fact that research is often contradictory. It may be a case of 'moderation in all things', and as perchance dreamer says, they didn't subgroup the different types of carnitine. This page has some good info about carnitine:

http://www.umm.edu/altmed/articles/carnitine-l-000291.htm
 

jimells

Senior Member
Messages
2,009
Location
northern Maine
I realize that 'health news' articles are generally worthless, but this one has more holes than swiss cheese. Perhaps the actual research paper is a little more solid.


the intestines can convert substances found in choline, a common dietary fat, to a by-product known as TMAO, trimethylamine-N-oxide. This new study looked at l-carnitine, which has a similar chemical structure to choline.

The study blames l-carnitine for the TMAO, but what about the choline, "a common dietary fat". Did the study exclude all choline from the participant's diet?

Hazen's group also compared mice fed their normal chow, which is basically a vegetarian diet, with mice whose food was supplemented with carnitine.

I've never seen a mouse eat a steak (I have seen where they ate butter!). A recent article (here on PR, perhaps?) criticized the overuse of mouse models in studying human diseases. Seems like they need to breed carnivorous mice for this kind of research.

chronic ingestion of carnitine
This is a wonderful phrase if one is writing propaganda. Makes it sounds like a disease. How about a study to find out if "chronic ingestion of health news" corelates to anxiety?

carnitine levels could quite strongly predict participant's risk of existing coronary artery disease, as well as the risk of having a major cardiac event, such as heart attack, stroke, or death over a three-year period, but only in adults who had high blood levels of TMAO.
That's a pretty big "but" stuck at the end of a long sentence, where it can be easily overlooked. It seems to imply that some participants had high carnitine levels, low TMAO, and lower risk of cardiac disease. So how do they conclude that high carnitine corelates to high risk of heart disease?


comparing 51 people who normally eat meat to 23 people who were vegetarian or vegan (who consume no animal products). The researchers found that adults who avoid meat and eat fewer animal products produced much lower concentrations of TMAO in the blood compared with the meat eaters.
But do the meat eaters in this study have less heart disease and live longer? If so, the author 'forgot' to tell us.

Perhaps the actual study has something useful in it. But for my money, the best use of the health news article would be to print it out and use it to start a fire in the wood stove.
 

MeSci

ME/CFS since 1995; activity level 6?
Messages
8,231
Location
Cornwall, UK
The carnitine issue was looked at in last night's BBC Radio 4 programme 'Inside Health'. It's repeated today and can be downloaded (at least in the UK - not sure about elsewhere). The programme has a tendency to be rather patronising and lowbrow, but the webpage has some links which may be useful. There was another item about head injury and hypopituitarism which I will mention in more detail in another thread.

The webpage is here:

http://www.bbc.co.uk/programmes/b01rr37c
 

Little Bluestem

All Good Things Must Come to an End
Messages
4,930
Even Dr. Sinatra is recommending only 2 - 3 servings of 3 - 4 oz. of hormone-free red meat per week. I am still not convinced.

Re: BBC Radio 4 - lowbrow suits my cognitive state.
 

MeSci

ME/CFS since 1995; activity level 6?
Messages
8,231
Location
Cornwall, UK
?

I've never seen a mouse eat a steak (I have seen where they ate butter!). A recent article (here on PR, perhaps?) criticized the overuse of mouse models in studying human diseases. Seems like they need to breed carnivorous mice for this kind of research.

That is a major flaw in using rodent models for anything to do with human food consumption. Rodents are almost exclusively herbivorous. I know that mice are traditionally regarded as liking cheese but, in my own experience of rescuing innumerable rodents from my cats, what they really like, and thrive on, are peanuts, seeds and fruit.
 

dbkita

Senior Member
Messages
655
The microbiome is a fascinating thing. But what the author does not explain is how to rectify that carnitine is used by cv doctors to help yhose with afib and those recovering from various heart disorders including MI. Your heart is a muscle. Depriving your mitochondria of fat transport for fuel is not I think what nature intended. Still this suggests imo moderation is in order. Check out for example how badly valproic acid crushes carnitine transport and read the associated effects. Not fun. Then again if all us working well methylation cycle makes most of the body's carnitine anyways.
 

Waverunner

Senior Member
Messages
1,079
Adding to the confusion :D

http://www.sciencedaily.com/releases/2013/04/130412132321.htm
Apr. 11, 2013 — L-carnitine significantly improves cardiac health in patients after a heart attack, say a multicenter team of investigators in a study published today in Mayo Clinic Proceedings. Their findings, based on analysis of key controlled trials, associate L-carnitine with significant reduction in death from all causes and a highly significant reduction in ventricular arrhythmias and anginal attacks following a heart attack, compared with placebo or control...
 

sianrecovery

Senior Member
Messages
828
Location
Manchester UK
The carnitine issue was looked at in last night's BBC Radio 4 programme 'Inside Health'. It's repeated today and can be downloaded (at least in the UK - not sure about elsewhere). The programme has a tendency to be rather patronising and lowbrow, but the webpage has some links which may be useful. There was another item about head injury and hypopituitarism which I will mention in more detail in another thread.

The webpage is here:

http://www.bbc.co.uk/programmes/b01rr37c

thanks for posting this - I missed the discussion of hypopituitarism, but my husband heard it, and it sounds interesting. Will have a look.
 

caledonia

Senior Member
Yes, that's how I got to this thread. I read the article. It looks like they don't know how to address TMAO yet, so for now they would recommend reducing their food (l-carnitine).

Maybe you don't directly reduce TMAO. Maybe you find out why some people have more TMAO than others, and go after it that way.
 

Victronix

Senior Member
Messages
418
Location
California
There's another one out now also that implicates lecithin --

Intestinal Flora May Promote Atherosclerosis
http://www.medpagetoday.com/Cardiology/Atherosclerosis/38664
But avoiding excessive consumption of the major sources of lecithin (also known as phosphatidylcholine) -- eggs, liver, beef, and pork -- should help keep TMAO levels down, they suggested.
also:
One limitation of the study was that it couldn't provide a mechanism for how TMAO promotes atherothrombosis, Loscalzo noted. He suggested a possible role in promoting vascular injury via its action as an oxidant that consumes thiol-reducing equivalents, including glutathione.

So presumably if you can increase your levels of glutathione and that could offset TMAO vascular injury . . . ?

If so, might this in the end this may come down to a decent balance of antioxidants, rather than avoiding any meat or eggs or semi-essential nutrients like choline?