Wednesday, May 14, 2014

L-Carnitine, red meat, and heart disease

In a recent article that hit most every newsroom last week, red meat kills people again.  Here is a link to one of the articles (1) and here is a link to the actual study (2).  The headlines that hit the newsstands were along the line of, "Red meat increases heart disease!" and things along that nature.  If the rate that nutritional information does a flip flop doesn't normally give you vertigo, it will today.  In an article published less than a week later, researchers note that an increase in L-Carnitine is protective in people who have just experienced a heart attack (3).  Before I show you why you should not rely on the news media to dictate your lifestyle choices, let's look at what each study showed.

In the first study, researchers compared the effect of L-Carnitine supplementation between meat eaters to non-meat eaters.  In meat eaters, bacteria in the gut fermented L-Carnitine in to TMAO, a chemical known to accelerate atherosclerosis while this effect was non-existent in non-meat eaters.  Since L-Carnitine is high in red meat, researchers believed that constant red meat consumption led to changes in gut flora that promotes an environment beneficial to creation of TMAO.  So, excessive red meat consumption leads to higher levels of bacteria that convert Carnitine to TMAO and this can increase atherosclerosis.  Check!

The second study was a meta analysis (Large study evaluating many studies) and found that using L-Carnitine was beneficial in the recovery from a heart attack.  People who used L-Carnitine were less likely to die from any cause, were less likely to experience arrythmia, less likely to experience angina, and had smaller infarct size than those who did not use L-Carnitine.  So, Carnitine conveyed a benefit to the person using it, specifically for heart health.

These 2 contradictory studies highlight a couple of problems.  First, the headlines that state, "Red meat increases heart disease" are wrong.  Having a specific type of gut flora that may be found in meat eaters would indicate you shouldn't take L-Carnitine supplements.  If you don't eat tons of red meat you are unlikely to have gut flora indicative of the people in this study that had a problem with TMAO.  Next, by looking at the study we can find the limitations of what the study can say.  One thing of note was that this study did not control for veggie intake.  What if the benefit of being vegan wasn't that you are not eating red meat, but that vegetable intake is high?  A meat eater that eats a lot of vegetables would have very different gut flora than a meat eater who eats none.  Maybe the vegan diet is beneficial because of the high vegetable intake, not because of a lack of meat.  This is one of the reasons the Synergy Wellness Program recommends a large diversity of foods.  A larger diversity of foods allows the bacteria in your gut to be diverse, preventing pathogenic bacteria from being able to grow to a capacity that could impact your health.

One of the problems with getting your science information from the popular press is that they seem to ignore what a study shows as well as the limitations study design put on what you can extract from a study.  When you see an article that one week shows coffee to be bad for you, then the following week find one that says it's bad for you, more often than not the problem isn't that the data is conflicting it's that people are ignoring the fact that certain types of data are not appropriate for drawing conclusions.  Even when the data is appropriate, the title of the article is meant to grab your attention, not be scientifically accurate.  Keep this in mind whenever you are looking at "science" in the popular press.