What makes red meat an enemy of the heart? Does it increase your risk of heart disease?

Like any other carnivore, 32-year-old Pranjal Seth had grown up with a hearty goat meat curry as a Sunday staple. But since genetics do not favour him, what with his family members having developed heart problems over the years, he has revised his eating habits. But he has always wanted to know how mutton damages his heart and whether he can be allowed occasional indulgence.
Now a research paper has zeroed in on the reason why a diet high in red meat raises the risk of heart disease. It has also found how this could make some people more susceptible to the cardiovascular effects of red meat. Turns out, this food trigger rests in the gut.
According to a study published earlier this month the American Heart Association (AHA) journal, Arteriosclerosis, Thrombosis, and Vascular Biology, a metabolite called trimethylamine N-oxide (TMAO) is released when gut microbes metabolise phosphatidylcholine (PC), a chemical found in red meat and egg yolks. Now this accelerates blood clotting and plaque formation in animal blood vessels. Higher TMAO levels have been linked to a higher risk of death in people who have heart disease. According to the study’s lead co-author, Meng Wang, PhD, a post-doctoral fellow at the Friedman School of Nutrition Science and Policy at Tufts University in Somerville, Massachusetts, TMAO has been on the radar of researchers for years. “We also know that TMAO can be produced our gut microbes during digestion of red meat and other foods that come from animals. In theory this could potentially explain why eating red meat increases the risk of cardiovascular disease (CVD),” she was quoted as saying. Now researchers are looking to assess to what extent meat consumption increased levels of TMAO, which raises cardiac risk.
WHAT IS A METABOLITE?
Reacting to the study, Dr Ajay Kaul, Chairman, Cardiac Sciences, Fortis Hospital, Noida, says, “This was known for a very long time that consumption of red meat causes a higher incidence of heart attacks when compared to white meat which comprises fish and chicken without the skin. It has been recently found that there is a metabolite that is released while the red meat is digested, which is the reason for a higher incidence of heart attacks in people consuming large amounts of red meat. This new chemical is due to the activity of normal microbes inside our intestine. Excessive consumption of red meat increases the level of LDL, which is bad cholesterol, and also makes us prone to blood clotting and plaque formation inside blood vessels. It is also important to understand that red meat contains a lot of fat, cholesterol and sodium content. These not only increase the risk of heart diseases but also elevate blood pressure. Red meat, beef, pork, and lamb have more saturated fat than chicken and fish.”
THE RISK ASSOCIATED WITH DIFFERENT MEATS
Grading the heart risk of several meats, Dr Kaul says, “You can say goat liver itself has a very high quantity of proteins, vitamin B, vitamin A, vitamin B12, folic acid and zinc. Lamb has more saturated fat, which is bad cholesterol, and puts you at a high risk of cardiovascular diseases than the other meats. It’s actually lamb meat which is the worst and we should understand that excessive amounts of fat contained in lamb are also very harmful.”
SHOULD WE GIVE UP EATING RED MEAT ENTIRELY?
“The answer is no, if it’s consumed within limits then it’s fine. Having three portions per week which is cumulatively around 300 grams is fine. Of course, the study also indicates a possibility of differing impacts because the gut microbiome in each person reacts differently. How each body reacts to different foods could help nutritions determine the best diet for each individual, “ advises Dr Kaul.
The new research included nearly 4,000 Americans older than 65, whose health and diets were tracked over decades as part of the Cardiovascular Health Study (CHS). Almost two-thirds of the participants were female and almost 90 per cent were White. The participants were tracked for at least 12 years, while some were followed for more than 20 years. In addition to diet, the study tracked blood biomarkers of TMAO and two related metabolites, gamma-butyrobetaine (GBB), and crotonobetaine, which both come from a chemical in red meat called L-carnitine. In the study, a person’s risk of CVD increased 22 per cent for every portion of red meat, especially processed meat, that they consumed daily.