by Charles Poliquin
Red Meat ScareHave vegans and vegetarians finally found the holy grail of research studies: a peer-reviewed, scientific study that establishes a direct link between heart disease and eating meat? Well, one thing is for sure – a new study on this topic has captured the attention of the mainstream media, making the headlines of news programs on NBC, CBS, CNN and even NPR. Is this the end of Paleo and the resurgence of carrot stick diets and wheatgrass smoothies? Not quite.
The interest in such a study is obvious – heart disease, according to the government supported Centers for Disease Control and Prevention, is the number-one cause of death in the United States. On a world scale, heart disease also ranks at or near the top, although in low-income countries diarrheal diseases and HIV/AIDS are higher on the list than lower respiratory infections and heart disease. Death would not “take a holiday” if all heart disease were eradicated (we all have to die of something, after all), but certainly a healthy-heart lifestyle could increase longevity.
Before getting into the details of this study on the effects of carnitine (which is found in red meat) that was conducted at the Cleveland Clinic in Cleveland, Ohio, let’s look at the big picture. Certainly, if red meat were as bad as the tree huggers say it is, then it would follow that those countries with the highest meat consumption would have the highest death rates from heart disease. This is not the case.
In looking for an association between meat consumption and heart disease, you’ll find that in the US the average meat consumption per capita is 120.2 kilos per year, followed by Australia (115.5) and New Zealand (106.4). At the bottom of the meat lovers’ scale are Bangladesh, with just four kilos of meat consumed each year, India (4.4) and Pakistan (4.7). Now consider that in these latter three countries, the death rate from heart disease is more than three times as high as the rate in the countries having the highest meat/carnitine consumption. At the very least, this data suggests that it is difficult to isolate a single cause for the prevalence of heart disease.
Many of the bold headlines about this study, such as “Red Meat Linked to Heart Disease,” are misleading. What the study actually found was that a chemical byproduct of gut bacteria called trimethylamine N-oxide (TMAO) enters the bloodstream and correlates to an increased building of plaque on the arteries. So forget about trying to develop a direct cause-and-effect association between red meat and heart disease – what we’re dealing with is a problem with gut bacteria. In fact, the researchers found that one solution to this problem, although radical, was the administration of broad-spectrum antibiotics. The headlines should have been “Fix Your Gut, Fix Your Heart!”
Before critiquing the researchers’ conclusions, let’s just remind ourselves that all meat is not created equal. Meat that comes from a concentrated animal feeding operation (aka industrial meat) is often treated with antibiotics that alter gut bacteria. Although the study did not address the organic-nonorganic aspect, it’s doubtful that the participants in the Cleveland Clinic study consumed grass-fed, organic meat. The use of organic meat consumption in the United States is quite low due to its cost.
How about the fact that the researchers were making correlations between research done on humans and research done on mice? And those mice were not even normal mice; they were genetically altered rodents who had been engineered to have a higher sensitivity to heart disease. And the subjects in the human studies were not representative of an average population, as they already had heart disease!
Excessive and chronic inflammation is linked to heart disease, but research presented this year at the Proceedings of the National Academy of Sciences concluded that inflammatory stress models developed for mice are not necessarily relevant to humans. The presenters noted, “…although acute inflammatory stresses from different etiologies result in highly similar genomic responses in humans, the responses in corresponding mouse models correlate poorly with the human conditions and, also, one another.”
Another issue with the mice studies is the amount of carnitine administered to the mice. The amount of carnitine given to the mice was 3,250 mg/kg. For an average human adult who weighs 70 kilos, that would equal a daily dosage of 18,446 mg. If a pound of meat contains 454 mg of carnitine, you’re looking at about 40 pounds of meat a day. World champion hot dog eater Takeru Kobayashi can scarf down 69 hot dogs in 10 minutes, but even he would have a hard time consuming about a quarter of his bodyweight in meat a day!
Another issue is that there is an assumption that serum TMAO levels are increased only by red meat. According to a research study published in 1999 involving six human subjects, many other foods can increase TMAO excretion levels far more than red meat, such as peanuts, tomatoes, peas, cauliflower and (pay attention, vegans and vegetarians) soy beans.
Can carnitine cause heart disease? An interesting question, but if you follow the science and consider the research parameters and limitations of the Cleveland Clinic study, it’s a question that has not been answered.
www.charlespoliquin.com
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