Red meat is bad for your heart health. This basic fact is pretty well-known all over the world and supported by many studies over the years. The American Heart Association says that red meats like beef, pork and lamb have more saturated fats than chicken, fish and vegetable sources of protein do. Saturated and trans fats are known to increase your blood cholesterol levels and lead to either the onset of heart disease or make a pre-existing heart condition worse.
According to the US National Institutes of Health, it’s not just the saturated fats in red meat that lead to heart diseases. Some nutrients in red meat promote the production of trimethylamine N-oxide (TMAO) by the gut bacteria, which is known to cause heart disease by enhancing cholesterol deposits in the arterial walls. Studies also show that TMAO interacts with blood platelets and interferes with normal blood clotting responses – another risk factor for heart disease and strokes.
Why this link isn’t as simple as that
A new study published in The BMJ suggests that although it’s true that red meat consumption is linked to a higher risk of heart disease, the link between the two is actually more complicated.
The researchers behind this study point out that studies do not explain how, for example, populations that have low consumption of red meat still have a higher risk of heart disease. This is especially true for the Indian population.
The researchers also state that most studies do not account for variable quantities and frequency of red meat consumption, differences in processed and unprocessed red meat consumption, and most importantly, the differences between comparable sources of protein to red meat.
To address these inadequacies, this new study examines the relation between the consumption of total, processed and unprocessed red meat and the risk of coronary heart disease (CHD). The researchers also estimated the effects of substituting other protein sources for red meat and the subsequent CHD risk with this diet change.
Red meat, plant and other proteins and CHD risks
The researchers collected data from the Health Professionals Follow-Up Study which includes detailed medical history, lifestyle and diet data of 51,529 American male dentists, veterinary surgeons, pharmacists, optometrists, osteopathic physicians, etc.
The researchers selected 43,272 of these health professionals because they did not have cardiovascular diseases or cancer at the time of enrollment in the study. Over an estimated 30 years of follow-ups, the researchers found 4,456 cases of CHD, of which 1,860 were fatal.
The researchers also found that among all the participants, those with higher total red meat consumption were more likely to smoke, consume alcohol, have diabetes and use aspirin regularly. These participants also had a higher intake of total energy and trans fats and were less physically active too. At the same time, they had a lower intake of multivitamins, fruits, vegetables and cereal fibers as compared to those whose red meat intake was lower: just one-fifth of their total diet.
This clearly indicates that those who have a red meat-dominated diet tend to have overall unhealthy eating and lifestyle habits too.
Further analysis showed the researchers that higher intake of total red meat, unprocessed red meat and processed red meat were each positively associated with a higher risk of CHD. Consuming one serving per day of total red meat was associated with a 12 percent higher risk of CHD, while one serving per day of unprocessed red meat and processed red meat increased CHD risks by 11 percent and 15 percent respectively.
Compared to red meat, consuming one serving per day of combined plant proteins (nuts, seeds, lentils and legumes, soy) was associated with a 14 percent reduced risk of CHD. In men over 65 years of age, the consumption of plant proteins reduced CHD risks by 18 percent while red meat consumption increased CHD risks by 17 percent.
The researchers also found that those who consumed a serving each or dairy products or eggs also had considerably lower CHD risk. They, therefore, concluded that substituting red meat (total, processed and unprocessed) with high-quality plant-based foods like legumes, nuts and soy can reduce the risk of CHD. Substituting total red meat with whole grains and dairy products and processed red meat with eggs might also reduce CHD risks, the study concluded.
For more information, read our article on Coronary artery disease.
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