Japanese study on eggs and mortality is not scientifically sound

Jul 29 2004

Representatives of the American Egg Board's Egg Nutrition Center as well as independent scientists say that a just-released Japanese study on eggs and mortality is not scientifically sound because the subset of women studied was too small to deliver accurate data.

In addition, experts say that the results of the study, which claimed that women who ate two or more eggs a day were more likely to die than women who ate less eggs, are misleading because just as many women died in the group who ate the least amount of eggs as did among those who ate the most eggs.

What's more, the study does not account for almost 50% of the causes of death of the study participants who were reported more likely to die of "any cause" -- including old age, smoking, complications from obesity, among an assortment of other factors (i.e., getting hit by a car) that can lead to one's demise. Specifically, experts point to the following as examples of sloppy and misleading research findings:

• The women who had higher rates of death from heart disease and stroke were statistically insignificant as too few women overall died of either cause, but, rather, most women died from "other causes." If cholesterol in eggs was a factor than heart disease and stroke deaths among women should have increased and they did not.
• The study did not require participants to provide other dietary intake information nor did it allow for lifestyle factors. Besides eggs, what else were the women eating? Did their daily diet consist of foods high in saturated fats? Aside from overall diet, was the group active or sedentary? Research has shown that poor diet and a lack of exercise are key factors in increasing one's mortality rate.
• Women in the study who ate two or more eggs a week were older and had more hypertension, twice the incidence of diabetes and were heavier smokers than other study participants.
• The study is at odds with U.S. studies that have shown no such link between egg consumption and increased mortality rates among women.

U.S. Studies Show Positive Findings for Eggs

• A longer-term study done at Harvard University that adjusted for risk factors found no increased risk from egg consumption. The American Heart Association no longer limits the amount of eggs a person can consume as long as their cholesterol is in check. Additional research studies have shown that eggs may actually help prevent heart disease, age-related macular degeneration and enhance memory function in a growing fetus.