Have you heard about the recent study connecting red meat with heart disease? Briefly the theory holds that carnitine, an amino acid found in red meat, is converted in the intestine to trimethylamine oxide (TMAO) by bacteria found in omnivores (people who regularly eat meat) but not in vegetarians. High blood levels of TMAO had previously been correlated with atherosclerosis, providing a new explanation for red meat as a risk factor for heart disease (besides its content of saturated fat and cholesterol).
Well, don’t swear off steaks just yet. The New York Times article questions whether the association between high TMAO levels and heart disease is cause & effect (i.e. will lowering TMAO reduce your risk?) and concludes “the study does not mean that red meat is entirely bad or that it is best to avoid it entirely…”
Chris Masterjohn, writing for the Weston A. Price Foundation, critiques this study raising other questions and objections:
• a 1999 study showed that beef did not generate significantly more (and often less) TMAO than most other foods including chicken and pork; vegetables such as carrots, cauliflower, peas, and tomatoes; and milk, eggs and bread
• the only foods in the 1999 study which produced significantly more TMAO than beef (up to 100 X higher!) was seafood, which of course is known to lower the risk of heart disease
• the steak eating experiment studied only 5 people – one vegan and 5 omnivores – and the results were too varied to draw any firm conclusions
• numerous studies have shown that carnitine supplementation is beneficial to patients with heart disease
• finally, the whole premise of red meat and heart disease is debatable. Masterson writes “…the balance of epidemiological evidence fails to show an association between fresh, unprocessed red meat and heart disease.”
So don’t give up your steaks yet, at least not based on this study.
"Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis" Nat Med. 2013 May;19(5):576-85
New York Times article
Culprit in Heart Disease Goes Beyond Meat’s Fat" New York Times, Gina Kolata, 7 April 2013
Weston A. Price Foundation - critique
Does Carnitine From Red Meat Contribute to Heart Disease Through Intestinal Bacterial Metabolism to TMAO? Chris Masterjohn, 10 April 2013
Mercola.com article - more on the subject
Will Eating Meat Really Increase Your Risk of Heart Disease? 22 April 2013
For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.