BEIJING — General advice on heart health used to be avoid eating too many eggs because of their cholesterol levels, but new research from China links one egg a day to reduced risk of heart problems, including death, by double-digit percentages.
Researchers from China and the United Kingdom used data from 416,213 people in the China Kadoorie Bank study who were free of cancer, cardiovascular disease and diabetes at baseline. At baseline, 13.1% reported daily consumption of eggs (averaging about 5.3 eggs per week), and 9.1% reported never or very rare consumption (averaging about 2 eggs per week).
Over a median follow-up of nearly nine years, there were 83,977 cases of cardiovascular disease and 9,985 deaths from cardiovascular disease. After multivariate adjustment, inverse associations were found to be significant between egg consumption and cardiovascular disease.
Those who consumed eggs daily had an 18% lower risk of death from cardiovascular disease. They also had a 26% lower risk of haemorrhagic stroke, which has a high prevalence rate in China, and a 28% lower risk of death from haemorrhagic stroke. The reduced risk of ischaemic heart disease was 12%. The daily consumers of eggs were more likely to have a higher level of education and household income, to have a new affluence dietary pattern, and to take multivitamins.
“The present study finds that there is an association between moderate level of egg consumption (up to one egg a day) and a lower cardiac event rate,” the study’s authors concluded. “Our findings contribute scientific evidence to the dietary guidelines with regard to egg consumption for the healthy Chinese adult.”
The study, published in the journal Heart, may be found here.
While being a source of dietary cholesterol, eggs also contain protein, vitamins and bioactive components such as phospholipids and carotenoids, the study pointed out. Egg-derived phospholipids have been shown to raise H.D.L. (good cholesterol) levels. Egg protein has been shown to result in greater satiety, and intake of eggs has been shown to increase plasma lutein and zeaxanthin, which play roles in protecting against oxidation, inflammation and atherosclerosis.
The researchers pointed out the study was lacking in people who consume more than one egg per day, which restricted them from assessing the association between higher egg consumption and the risk of cardiovascular disease. The study, which collected information on habitual egg consumption at baseline, also might not reflect dietary habits over the follow-up period.
Lead researchers were from the School of Public Health, Peking University Health Science Center. The study was supported by grants from the National Natural Science Foundation of China, the National Key Research and Development Program of China, the Kadoorie Charitable Foundation in Hong Kong, the Wellcome Trust in the United Kingdom and the Chinese Ministry of Science and Technology.
Dietary guidelines from the Chinese Nutrition Society recommend healthy adults consume 40 to 50 grams of egg (about 0.8 to 1 egg) per day. The upper limit of cholesterol recently was cancelled.
The Dietary Guidelines for Americans previously recommended people limit consumption of dietary cholesterol to 300 mg per day, but the Dietary Guidelines for Americans 2015-2020 does not. The most recent Dietary Guidelines does say people should eat as little dietary cholesterol as possible while consuming a healthy eating pattern.
“Strong evidence from mostly prospective cohort studies but also randomized controlled trials has shown that eating patterns that include lower intake of dietary cholesterol are associated with reduced risk of C.V.D., and moderate evidence indicates that these eating patterns are associated with reduced risk of obesity,” the Guidelines said, adding that more research is needed about the dose-response relationship between dietary cholesterol and blood cholesterol and that adequate evidence is not available for a quantitative limit for dietary cholesterol specific to the Dietary Guidelines.