Posted on 04/08/2013 1:49:21 PM PDT by neverdem
Gut bacteria may convert a nutrient found in red meat into a compound that can damage the heart
The link between red meat and poor heart health has traditionally been blamed on cholesterol, but new evidence suggests this isn't the whole story. US researchers found that carnitine, a nutrient found in red meat, is converted into a metabolite that promotes cardiovascular disease by gut bacteria. This may mean that the popular practice of taking carnitine supplements to build muscle is unwise.
‘The cholesterol and saturated fat content of red meat is not sufficient to account for increased cardiac risk,’ says lead author Stanley Hazen of Cleveland Clinic, Ohio. ‘There’s always been an argument that something else is contributing to that association.’
He says that he began to suspect carnitine when investigating trimethylamine N-oxide (TMAO), which promotes atherosclerosis – hardening of the arteries – in mice by altering cholesterol metabolism. TMAO is produced by gut bacteria when they break down choline, a trimethylamine-containing compound found in the head of phospholipids. Hazen and his colleagues suspected that carnitine, which also contains trimethylamine, was processed in a similar way by TMAO-generating bacteria. They confirmed this using a radioactive label to trace the fate of carnitine eaten by volunteers, which was subsequently detected in TMAO in the blood. Mouse studies then revealed a link between carnitine and atherosclerosis, although carnitine itself did not appear to have a direct effect.
Gut flora convert carnitine and choline to trimethylamine and enzymatic oxidation converts this to a heart harming molecule © NPG
‘We found that if you add carnitine to the diet you get enhanced atherosclerosis, but only in the presence of intact gut flora,’ explains Hazen. ‘If you give the mice broad spectrum antibiotics and suppress their ability to make TMAO, dietary carnitine has no effect.’
The team also surveyed over 2500 people and found a significant association between blood carnitine levels and cardiovascular disease risk, even after controlling for other risk factors.
Victoria Taylor, a senior dietician at the British Heart Foundation, says this is an interesting discovery. ‘The findings won’t necessarily mean a change to existing recommendations,’ she says, ‘but this has served up a good reminder for us to think about alternative sources of protein if we eat a lot of red meat.’
Those taking carnitine pills as a dietary supplement may also be at risk, notes Hazen. Though currently marketed as an aid to weight loss or muscle building, its effects on heart health have never been investigated. ‘Our data suggest that if you chronically ingest carnitine you’re shifting your metabolism and becoming more susceptible to cardiovascular disease,’ he says. ‘I think more studies are needed to look at the safety of long-term supplementation.’
R A Koeth et al, Nat. Med., 2013, DOI: 10.1038/nm.3145
Obamanomics has taken care of that for me. Can’t afford it.
I guess it’s too late for me, I intend to keep eating it.
The Choice cuts are too expensive, but I can still afford ground beef and a New york strip once in a while.
Not me. Gave up meat and dairy in May, and I gotta say, I don’t miss it a bit.
Heck I killed off all my gut flora with hot sauce, tumeric, hot peppers, kimchi, chili, curry, jalapenos, vinegar and paprika - hahah!
I'll continue my L-Carnitine supplements for now.
L-carnitine prevents the progression of atherosclerotic lesions
Chairman Obama says Health and Human Services bureaucrats have identified a strict diet of water and cardboard helps reduce health risks for all you peons out there. Eat up comrades!
http://i45.tinypic.com/5mlelk.jpg
red meat alert
The problem is people that want to live forever..
Of one thing I am certain... I am grateful that I was not born a mouse, especially in a lab. ;>)
About 5 years ago I lost a good friend. He was known by all of my neighbors as, The Tractor Guy. He was a meat and potatoes man. He had worked hard all of his life and was never overweight, but in his later years he suffered from diabetes. He lost half of his right foot, but this tough old guy still cut, baled and brought in his own hay — at the young age of 86.
All of those meat eating days finally caught up to him..... and my dear friend passed away at the age of 96.
—For me, everything in moderation.
They totally neglected the 500 pound gorilla in the room.
That is, *what* bacteria is doing this?
Typically, our digestive system is so oriented to digesting meat that we don’t need the help of bacteria to do so, until E. Coli, very late in the digestive game, squeezes out some of the last nutrients from the feces.
As an alternative line of thinking, since 1957 it was known that a shortage of magnesium in the body could cause several cardio problems, including atherosclerosis. This knowledge fell out of fashion, with cholesterol and other things blamed, but it still remains as a prime suspect.
In the News/Activism forum, on a thread titled New culprit for red meat health risks, Jed Eckert wrote:
Many studies have shown L-Carnitine to have the exact opposite effect on atherosclerosis that this study shows. It has been shown to help the heart and the arteries.
I’ll continue my L-Carnitine supplements for now.
Unaware of what my brother was ingesting. It included that stuff. I found him unresponsive slumped on the bathroom floor. Massive stroke. Prononuced dead next day. Suit yourself if your taking that stuff.
Don’t mind all the wise guys. I appreciate the medical info you post.
I also appreciate the wise guys’ wise cracks. ;-)
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