Switching from red meat to chicken to keep your cholesterol down may not be a great strategy, according to a new study this Tuesday. It found that people’s blood cholesterol levels rose similarly when they ate a diet filled with either red or white meat, compared to a diet without meat.
This effect on cholesterol, however, may not be as bad for your heart as it seems at first glance.
Researchers at the Children’s Hospital Oakland Research Institute (CHORI) recruited more than 100 healthy volunteers for their diet experiment. They split them into two broad groups, with one group getting a diet high in saturated fats, while the other had a diet low in them. Both groups were then further split into three more batches.
For four weeks at a time, chosen in random order, the volunteers would eat a diet high in white meat, red meat, or non-animal proteins, then rotate to the other diets. Along the way, their blood would be tested for levels of total cholesterol as well as low-density lipoprotein, or LDL, cholesterol—the “bad” kind of cholesterol that can cause a build-up of plaque in our arteries and raise the risk of heart disease and stroke.
According to senior study author Ronald Krauss, the director of Atherosclerosis Research at CHORI, theirs is the first study to directly compare the effects of red meat, white meat, and non-meat sources of protein on cholesterol levels in diets where other major nutrients were kept constant and saturated fat intake was controlled. And what they found was surprising, given the conventional wisdom surrounding white meat.
“Our new finding was that the level of LDL cholesterol was the same with both red meat and white meat, and that the LDL level was lower with plant-based protein,” Krauss told Gizmodo by email. “These results were similar whether or not the diets were high or low in saturated fat. So the result can be viewed as indicating either a cholesterol raising effect of both meats, or a cholesterol lowering effect of plant foods, or both.”
The study was published Tuesday in the American Journal of Clinical Nutrition.
The effects of cholesterol on heart health aren’t completely cut-and-dry, though, nor are the foods that can affect cholesterol levels. There are actually different kinds of LDL, characterised by the size of their particles. And while small and medium-size LDL is strongly linked to a higher risk of cardiovascular disease, the relationship is weaker for large-size LDL.
In the current study, eating both types of meat only led to higher levels of large-size LDL, not the other types. Eating saturated fats led to an increase in large-size LDL, but again, not the smaller types.
“Therefore, using standard LDL cholesterol level as the measure of cardiovascular risk may lead to overestimating that risk for both higher meat and saturated fat intakes, as the LDL cholesterol test may preferentially reflect levels of larger LDL particles,” Krauss said.
The study does have some caveats. For one, the team didn’t look at the effects of eating the other major white meat, fish, which often contains higher levels of healthier fats, like omega-3s, that are thought to lower overall cholesterol. Nor did they study processed products that are often made from red meat, such as bacon or beef sausages. Either of these factors could have made the comparison more favourable for white meat.
Still, since public health agencies have long recommended that people try to cut down on red meat and switch to white meat or vegetables as their major source of protein, this study’s findings do carry some important implications. Although there can still be reasons to prefer white meat over red for health reasons (a lower risk of cancer, for once), the authors say their findings suggest that having a diet high in plant-based proteins might be the best way to keep your cholesterol in check.
“All we can say from our study is that if you are trying to lower your cholesterol, limiting white poultry meat may be just as effective as limiting red meat,” said Krauss. “And since individuals may differ in their responses, a cholesterol test is the best way to see how the diet is working.”