Is eating eggs good for you or not? This has been a hotly debated subject for many years. Lately there have appeared a couple of studies suggesting that eating eggs does not affect cholesterol levels or risk of death later in life. Though the media was quick to spread this happy news, these studies were quickly put into proper perspective when it was pointed out that the absorption of cholesterol from food is not a straightforward linear process whereby increasing cholesterol in the diet leads to steadily increasing cholesterol in the blood. Instead blood cholesterol reaches a plateau after which its absorption slows down. In other words, if a person is eating little to no cholesterol, adding cholesterol from the diet will drastically increase the amount of cholesterol that ends up in their bloodstream. Conversely, the addition of more cholesterol-containing foods into the diet of someone already eating high levels (400 mg of cholesterol or 2 eggs daily on average) will result in a much smaller rise in blood cholesterol (1).
A very recent study, published March 15, 2019 is adding to our knowledge on the health outcomes of eating more cholesterol. This new research looked at dietary cholesterol, especially that from eggs, and its relationship to the risk for heart disease and early death (2). Researchers from Northwestern University in Illinois, USA followed 29,615 male and female participants for an average of 17.5 years. This study pooled data from six earlier prospective cohort studies that included ethnically diverse participants and followed them for up to 31 years. Data regarding the diet of participants was collected using self-reported food frequency questionnaires at the start of the study. Outcomes were adjusted for age, sex, race, education, smoking, exercise and other traits that could contribute to heart problems. Results remained significant even after controlling for diabetes, high blood pressure, obesity, blood cholesterol and other cardiovascular risk factors.
Results showed that (2);
Consumption of cholesterol, regardless of the source, was associated with increased risk of heart disease and early death from all causes. These risks go up as cholesterol intake increases.
Cholesterol was the driving factor of these associations independent of the consumption of saturated fat and other types of dietary fat or overall diet quality.
Overall each additional 300 mg intake of dietary cholesterol per day was associated with;
A 17% increased risk for cardiovascular disease
An 18% increased risk for early death from all causes
A 14% increased risk of heart failure
A 26% increased risk of stroke
Overall each additional half an egg consumed per day was associated with;
A 6% increased risk for cardiovascular disease
An 8% increased risk for early death from all causes
In women, each additional 300 mg intake of dietary cholesterol per day was associated with;
A 28% increased risk of early death from all causes
In women, each additional half an egg consumed per day was associated with;
A 13% higher risk of cardiovascular disease
A 16% increase in risk of early death from all causes
Researchers found that if two people were eating almost exactly the same diet except for differing amounts of eggs, whether the diet tended towards a standard Western diet or a healthy plant-based diet, the effect of even an extra half an egg a day on heart disease was measurable.
There are some limitations inherent in this investigation. For instance, participants were asked only once, at the start of the study, about their eating habits so this analysis cannot take into account any changes in diet along the way. However, the study does have strength in its large numbers of participants and the many years of follow-up, both of which give credibility to its conclusions.
This new study serves to reinforce our already formidable arsenal of evidence about the effects of dietary cholesterol on human health. We know that eating cholesterol does indeed increase blood cholesterol levels, unless they are already very high. We also know that higher blood cholesterol does lead to worse health outcomes. To date there exist more than 200 prospective cohort studies and randomized trials covering more than 2 million participants with 20 million person-years of follow-up that demonstrate consistently that the higher the LDL-cholesterol in the blood, the greater the risk of atherosclerotic cardiovascular disease (the build-up of fatty plaques in artery walls that can increase the risk of heart attacks, strokes and peripheral vascular disease) (3).
Eggs are the leading source of cholesterol in the standard Western diet. One large egg contains about 211 mg cholesterol (4). Other sources of cholesterol are meats of all kinds (including poultry and fish), dairy products and shellfish. There is no cholesterol in plant-based foods.
Should we cut back on egg consumption? Definitely. But we should also cut back on other sources of dietary cholesterol if we are looking for our best chance for a long, healthy life. Keep in mind that our bodies can make all the cholesterol we need so there is absolutely no need to eat it. Isn’t it time that you checked out the delicious and satisfying alternative of whole plant foods to supply the bulk of your calories?
1 Hopkins, P.N. Effects of dietary cholesterol on serum cholesterol: a meta-analysis and review. Am J Clin Nutr. 1992 Jun; 55(6):1060-1070.
2 Zhong, V.W., Van Horn, L., Cornelis, M.C., Wilkins, J.T., Ning, H., Carnethon, M.R. et al. Associations of dietary cholesterol or egg consumption with incident cardiovascular disease and mortality. JAMA. 2019;321(11):1081-1095.
3 Ference, B.A., Ginsberg, H.N., Graham, I., Ray, K.K., Packard, C.J., Bruckert, E., Hegele, R.A., Krauss, R.M., Raal, F.J., Schunkert, H., Watts, G.F., Borén, J., Fazio, S. et al. Low-density lipoproteins cause atherosclerotic cardiovascular disease. 1. Evidence from genetic, epidemiologic, and clinical studies. A consensus statement from the European Atherosclerosis Society Consensus Panel. Eur Heart J. 2017 Aug 21; 38(32):2459-2472.
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