Interest in high-protein and high-fat diets like the keto diet keeps growing, but concerns about the health effects of many foods on those diets remain high. For at least one of those foods—the simple protein-packed egg—a new, large-scale study suggests that devouring one a day is fine for most people, even those with a history of heart disease. That finding runs counter to old-school nutritional guidance, but lines up well with more recent science suggesting that we’ve demonized eggs for too long.
First, if you’re wondering why we should bother defending the egg aside from its role in high-protein diets, there are a few good reasons, namely that it’s a relatively cheap nutritional powerhouse full of iron, vitamins and minerals. Those merits have been overshadowed by the egg’s cholesterol and saturated fat content and fears that daily consumption may raise risk of heart disease (although in the last couple of decades we’ve seen a loosening of restrictions on eating eggs, most notably from the American Heart Association).
The latest study directly tackled the heart-health issue by assessing “the association of egg consumption with blood lipids, cardiovascular disease (CVD), and mortality in large global studies involving populations from low, middle-, and high-income countries.”
The researchers studied about 177,000 people total from 50 countries across six continents, using data from three previous long-term studies. Collectively, the studies provided a wealth of data on the association between diet and cardiovascular health against a range of cultural and socioeconomic backdrops. That’s an advantage over smaller studies that often focus on higher income groups.
The findings: “Moderate egg intake, which is about one egg per day in most people, does not increase the risk of cardiovascular disease or mortality even if people have a history of cardiovascular disease or diabetes,” said Mahshid Dehghan, the study’s first author and a researcher with the Population Health Research Institute (PHRI) at McMaster University.
“Also, no association was found between egg intake and blood cholesterol, its components or other risk factors,” Dehghan added in a press statement. “These results are robust and widely applicable to both healthy individuals and those with vascular disease.”
The key here, of course, is the word “moderate.” These findings suggest that “moderate” is about an egg a day, while older guidelines placed the line at about three per week.
These findings run counter to those from a headline-grabbing study published last year that claimed to find a link between egg consumption (an additional half an egg per day) and risk of cardiovascular disease. That study focused on a smaller population in the U.S. only, and the data was self-reported, which raised concerns about whether participants were correctly identifying sources of cholesterol in their diets (eggs vs. other sources).
The latest research doesn’t necessarily provide relief from cardiovascular concerns for hardcore egg lovers downing multiple eggs a day. Since most of the cholesterol and saturated fat is concentrated in the yokes, it’s still advisable for heavy eaters to limit how many yokes they munch and focus on the whites.
Also, this research doesn’t directly address how eggs are prepared. Frying eggs in certain oils obviously changes the health profile. Best bet, keep it clean and simple. And as with all dietary decisions, if you have heart disease or are at high risk of developing it, keep your doctor informed.
The study was published in The American Journal of Clinical Nutrition.