New Research On Red Meat And Heart Disease
Heart disease is the leading cause of death worldwide. An estimated 80 million Americans have one or more types of the deadly disease. For many years, numerous studies stressed the link between a diet high in saturated fat and cholesterol with hardening of the arteries. But critics of these studies doubted they had found the true dietary cause. Now, new research from doctors at the Cleveland Clinic finds that a compound in red meat and supplements leads to higher heart disease risk. For our Mind and Body Series: the latest research on red meat and what it might mean for heart disease treatment and prevention.
director of the division of cardiovascular sciences, National Heart, Lung, and Blood Institute (NHLBI) at the National Institutes of Health (NIH).
chair of the department of cellular and molecular medicine, Cleveland Clinic's Lerner Research Institute.
vice president of scientific and regulatory affairs for the Council for Responsible Nutrition.
executive director of human nutrition research at National Cattlemen's Beef Association (NCBA).
Ask The Expert About New Red Meat And Heart Disease Research
Is grass-fed, free-range meat healthier than other types of meat? Does carnitine affect vegans differently than non-vegans? How does the human body use carnitine? Dr. Michael Lauer answered these listener questions and more about the latest research on red meat and heart disease. Dr. Lauer is the director of the Division of Cardiovascular Sciences at the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health (NIH). Some questions have been edited for space and clarity.
Q: In what levels is L-carnitine present in other meat (aside from red) and dairy products, in comparison to the levels in red meat? – from Juliana via Facebook
A: Carnitine is found in much higher levels in red meat than in other foods. In 100g of red meat, there are 95 mg of carnitine; in 100g of chicken breast there are 3.9 mg of carnitine. In 100 ml of whole milk, there are 3.7 mg of carnitine. In contrast, in 100g of a green vegetable like asparagus there are only 0.2 mg of carnitine.
Q: Since bacteria in fish create TMA, how would fish fit into the dietary picture? – from Stephen via Facebook
A: This is a fascinating question. Some marine animals, in particular sharks and deeper sea fish have high concentrations of TMAO (the toxic metabolite of TMA) in their tissues. In sharks, TMAO counteracts the toxic effects of urea (a break-down product of protein). In other fish, TMAO counteracts the effects of high water pressure, pressure which would otherwise crush cells.
What are the implications for the dietary picture? We honestly don’t know. Dr. Stanley Hazen’s [a guest on the program] work suggests that TMAO generated through dietary carnitine and gut bacterial activity worsens an individual’s cholesterol profile and exacerbates blood vessel disease. We don’t know whether dietary fish TMAO is harmful.
Q: Is there a difference between eating grass-fed, free-range red meat vs. other types of red meat? – from kforselius via Web
A: Some people think so, though the evidence is not definitive. It has been argued that grass-fed, free-range red meat is leaner, with less fat. We don’t know whether we can reduce the risk of heart attack or stroke by substituting “standard” meat with grass-fed, free-range meat. It’s a hypothesis that would be worth testing.
Q: What about leaner red meats such as elk, buffalo and venison? – from Chris via Facebook
A: Same answer as above.
Q: What is carnitine used for by the body? – from Andrew via Facebook
A: We can think of carnitine as a “fuel injector.” It enables mitochondria, the “fuel cells” of the body, to take up fat; with the aid of carnitine, mitochondria can absorb fat and burn it for energy.
Q: What about the genotypes of people who eat red meat? There are markers for cardiovascular disease, were they looked at? Humans have been eating red meat for a long time. – from Marjorie via email