Worried About Diabetes or Your Heart? Eggs Not Harmful

Two recent studies suggest egg lovers aren’t at higher risk of type 2 diabetes or coronary artery disease. In a new meta-analysis, egg consumption was largely unrelated to risk of type 2 diabetes. And in a population study, egg consumption was not associated with increased incidence of coronary artery disease among men, even those with a genetic risk factor.

“It is important to keep in mind that eggs were only one of many foods people reported eating in these studies,” says Alice H. Lichtenstein, DSc, director of Tufts’ HNRCA Cardiovascular Nutrition Laboratory. “When isolating the independent effects of eggs within the context of a relatively modest range, one to two eggs per day, there seems to be little impact on health outcomes. Of course, that conclusion is based on the assumption that their frequent partners on the plate, bacon and sausage, or heavily buttered toast, are not present.”

Shifting views of the health effects of dietary cholesterol have contributed to a recent rehabilitation of eggs. Most scientists, along with the latest Dietary Guidelines for Americans, now say that the amount of dietary cholesterol in one large egg – 185 milligrams – doesn’t significantly contribute to unhealthy levels of cholesterol in your blood. (See the August 2015 newsletter.) But concerns have remained about eggs and diabetes risk, as well as about their cardiovascular effects on people genetically sensitive to dietary cholesterol.

LITTLE DIABETES DANGER: The meta-analysis, published in the American Journal of Clinical Nutrition, looked at 12 study populations totaling 219,979 individuals, 8,911 of whom developed type 2 diabetes. Overall, there was little difference in risk of diabetes between the highest and lowest categories of egg consumption; eating fewer than four eggs a week was not associated with diabetes risk. Researchers commented, “This is reassuring for individuals who rely on eggs as a source of affordable protein.”

Further analysis did reveal a modestly elevated risk of diabetes with more frequent consumption of eggs. And when results were broken out by geography, consumption of three or more eggs per week was associated with higher diabetes risk, but only in US studies.

One possible explanation for the US difference might involve the foods typically eaten here along with eggs. Americans’ preference for bacon and eggs, or other processed meats as egg accompaniments, might be responsible for the elevated diabetes risk – rather than egg consumption itself.

The study did not address the health effects of egg consumption on individuals who already have type 2 diabetes.

ARTERIES AND EGGS: A second study supports the updated thinking about egg consumption and blood cholesterol, as seen in coronary artery disease. Finnish researchers looked at data on 1,032 men, initially ages 42-60, participating in the Kuopio Ischemic Heart Disease Risk Factor Study. Over almost 21 years of followup, neither egg consumption nor dietary cholesterol intake was significantly associated with risk of coronary artery disease. The same was true for measurements of carotid intima-media thickness (IMT), used to diagnose the extent of carotid atherosclerotic vascular disease (“hardening” of the arteries serving the heart).

Participants’ average egg intake was about four per week – the equivalent of about one egg every other day. Dietary cholesterol intake from eggs contributed about 28% of total dietary cholesterol.

The study also looked at a subgroup of 32.5% of the men with the ApoE genetic variation, in whom the effect of dietary cholesterol on blood cholesterol is thought to be stronger. Even in this highly susceptible population, a modest intake of eggs and dietary cholesterol was not linked to greater risk of coronary artery disease or carotid IMT. In fact, eating more eggs was associated with a slightly lower risk among ApoE4 carriers

WHOLE FOODS: Publishing their findings in the American Journal of Clinical Nutrition, Jyrki K. Virtanen, PhD, of the University of Eastern Finland, and colleagues pointed out that eggs are more than merely a source of dietary cholesterol: “Eggs are an inexpensive and widely available source of several beneficial nutrients, such as high-quality protein, unsaturated fatty acids, vitamins and minerals. Eggs are also a good source of other bioactive compounds, such as lutein, zeaxanthin and phospholipids, which can have beneficial effects on inflammation, lipid oxidation, lipid metabolism and atherosclerosis progression.”

Therefore, the researchers concluded, the health effects of eggs – or any other food – cannot be reliably determined by a single nutrient in the food, such as cholesterol. “This emphasizes the need to investigate the impact of whole foods, rather than individual nutrients or food components, on health.”

As the nutritional negatives about eggs continue to crack, most people can safely include up to five to seven eggs per week in a balanced diet.

TO LEARN MORE: American Journal of Clinical Nutrition, March 2016—

http://dx.doi.org/10.3945/ajcn.115.122317

TO LEARN MORE: American Journal of Clinical Nutrition, February 2016—

http://dx.doi.org/10.3945/ajcn.115.119933