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Steak is bad for the heart and now we know why


“Red meat is bad for your heart”, that is typically the story we hear from people. While some might take this as meat is bad for us, or that it is wrong to eat red meat, science has been trying to find a better answer to that question. After all it wouldn’t do for science to say, it just does. Well as luck may have it, new research provides details on how gut bacteria turn a nutrient found in red meat into metabolites that increase the risk of developing heart disease. The findings may lead to new strategies for safeguarding individuals’ cardiovascular health.

Previous research by this same team revealed a pathway by which red meat can promote atherosclerosis, or hardening of the arteries. Essentially, bacteria in the gut convert L-carnitine, a nutrient abundant in red meat, into a compound called trimethylamine, which in turn changes to a metabolite named trimethylamine-N-oxide (TMAO), which promotes atherosclerosis.

Now the team, through extend their earlier research, identified another metabolite, called gamma-butyrobetaine. This new metabolite is generated to an even greater extent by gut bacteria after L-carnitine is ingested, and it too contributes to atherosclerosis.

The researchers found that gamma-butyrobetaine is produced as an intermediary metabolite by microbes at a rate that is 1,000-fold higher than the formation of trimethylamine in the gut, making it the most abundant metabolite generated from dietary L-carnitine by microbes in the mouse models examined. Moreover, gamma-butyrobetaine can itself be converted into trimethylamine and TMAO.

Interestingly, however, the bacteria that produce gamma-butyrobetaine from L-carnitine are different from the bacterial species that produce trimethylamine from L-carnitine.

The discovery that metabolism of L-carnitine involves two different gut microbial pathways, as well as different types of bacteria, suggests new targets for preventing atherosclerosis—for example, by inhibiting various bacterial enzymes or shifting gut bacterial composition with probiotics and other treatments.

“The findings identify the pathways and participants involved more clearly, and help identify targets for therapies for interventions to block or prevent heart disease development,” says Dr. Stanley Hazen, lead researcher.

“While this is into the future, the present studies may help us to develop an intervention that allows one to ‘have their steak and eat it too’ with less concern for developing heart disease.”

Well I don’t know about you, but I do enjoy a good steak, so the idea that it could be healthier is one that I look forward to.

Koeth RA, Wang Z, Levison BS, Buffa JA, Org E, Sheehy BT, Britt EB, Fu X, Wu Y, Li L, Smith JD, DiDonato JA, Chen J, Li H, Wu GD, Lewis JD, Warrier M, Brown JM, Krauss RM, Tang WH, Bushman FD, Lusis AJ, & Hazen SL (2013). Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis. Nature medicine, 19 (5), 576-85 PMID: 23563705

Robert A. Koeth, Bruce S. Levison, Miranda K. Culley, Jennifer A. Buff, Zeneng Wang, Jill C. Gregory, Elin Org, Yuping Wu, Lin Li, Jonathan D. Smith, W.H. Wilson Tang, Joseph A. DiDonato, Aldons J. Lusis, & Stanley L. Hazen (2014). g-Butyrobetaine is a proatherogenic intermediate in gut microbial metabolism of L-carnitine to TMAO Cell Press : 10.1016/j.cmet.2014.10.006.


10 responses

  1. Jesse

    orrrrrrr you could stop eating meat and focusing on eating healthier


    November 5, 2014 at 4:54 pm

    • Orrrrr you could eat meat if you are eating “healthier”, there is nothing wrong with meat eating, humans (among other animals) were made to eat meat. Saying meat in general isn’t healthy is just ignorant.


      November 5, 2014 at 5:20 pm

      • Heh_Vegans

        Vegans don’t care about evidence. They only care about animals, even if it means harming their own health.


        November 6, 2014 at 9:16 am

      • Hey plants have feelings too!


        November 6, 2014 at 9:32 am

  2. Pingback: Steak is bad for the heart and now we know why ...

  3. Unless you are a fruitarian and eat just the fruits and leaves of a plant, you still kill plants to survive. Gluten fucks up your colon and causes you leach nutrients. Oxygen eventually causes type mitochondria to screw up, which causes you to age and die. So stop with the propaganda scare.


    November 5, 2014 at 10:08 pm

    • I hope that wasn’t directed at me, I made it abundantly clear I love eating steak, among other things. I just found the reason red meat was deemed “bad” fascinating. That doesn’t mean you shouldn’t eat it, just that there is actual science behind the claim.


      November 6, 2014 at 7:47 am

  4. This is nonsense. We convert fish to much higher levels of TMAO yet fish has been proven to be cardio-protective.


    November 7, 2014 at 12:13 pm

    • Lovely, well publish your data in a peer reviewed journal and I will do a post on that next time. Personally, I don’t care one way or another I just thought this was a bit of interesting info and I make it abundantly clear I’m still a steak eater so it’s not like I have some ulterior motive here


      November 7, 2014 at 4:26 pm

  5. Pingback: Steak raises cancer risk and now we know why | Lunatic Laboratories

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