- The once-maligned egg may not be that bad after all — despite having more than twice the cholesterol compared to a Big Mac.
- Dietary cholesterol doesn’t have as much of an impact on blood cholesterol levels as was previously thought (the American Heart Association and latest 2015-2020 Dietary Guidelines for Americans no longer recommend limits on daily cholesterol consumption).
- Most of the cholesterol absorbed from our gut is manufactured by our body and only about 25% of cholesterol from a typical Western diet is absorbed
Some people have a genetic predisposition to absorb more cholesterol than others and carriers of the gene called Apo-E4 in general have higher cholesterol levels. Of interest, Finland has a higher number of Apo-E4 carriers -a genetic marker for increased dietary cholesterol absorption. A recent study from eastern Finland (Kuopio Ischaemic Heart Disease Risk Factor Study) looked at the question of increased dietary cholesterol and the development of cardiovascular disease and heart attack. This study was particularly interesting since it sheds more light on the long-held concern about eggs and heart attack risk.
More eggs higher cholesterol?
The 2016 study reported in the American Journal of Clinical Nutrition included people between the ages of 42 and 60 followed for 21 years, who on average consumed nearly 400 milligrams of dietary cholesterol plus one egg per day (one medium-sized egg has approximately 200 mg of cholesterol and a Big Mac only about 85 mg). The average daily consumption of cholesterol in the study was a whopping 520 mg. That’s a high cholesterol diet!
Surprisingly, the study reported that the consumption of eggs, a significant source of dietary cholesterol was not associated with either the progression of hardening of the artery disease in the carotid artery or any increase risk of heart attack. The findings suggest that a high-cholesterol diet (and/or the frequent consumption of eggs) does not increase the risk of cardiovascular diseases even in persons who are genetically predisposed to a greater effect of dietary cholesterol on serum cholesterol levels.
This study is consistent with other larger collections of studies (meta-analysis) with more than 3 million person-years of data that found no evidence of an association between egg consumption (one a day) and risk of heart attack (coronary heart disease) or stroke. In addition, people with higher egg consumption had a 25% lower risk of developing hemorrhagic stroke.
Remember an egg yolk in addition to cholesterol also has other important nutrients such as vitamins D, E, B12, folate, riboflavin, essential fats, choline, lutein, zeaxanthin, and protein that may improve health. The carotenoids lutein and zeaxanthin may reduce the risk of age-related macular degeneration, the leading cause of blindness in older adults. Eggs are considered to be one of the best sources of protein available. One medium-sized egg contains about 6 grams of complete protein (eggs contain all eight essential amino acids) and valuable minerals like calcium, zinc and iron.
Despite what you thought, an egg a day in the context of a healthy diet pattern does not appear to pose a risk for heart disease or significantly impact dietary cholesterol levels according to the totality of the research. But remember it’s the entire dietary pattern that is important: an egg a day on top of buttery biscuits and gravy is not the same as an occasional egg within the context of a Mediterranean dietary pattern. This concept is highlighted in the 2015 Dietary Guidelines for Americans Recommendations that now no longer restricts fat and other macronutrients for heart disease prevention but supports instead, dietary pattern-based recommendations, emphasizing foods that characterize healthy dietary patterns.
Hu FB, et al. A prospective study of egg consumption and risk of cardiovascular disease in men and women. JAMA. 1999; 281:1387-94.
Virtanen, JK, et al. Associations of egg and cholesterol intakes with carotid intima-media thickness and risk of incident coronary artery disease according to apolipoprotein E phenotype in men: the Kuopio Ischaemic Heart Disease Risk Factor Study. American Journal of Clinical Nutrition. 2016; DOI: 10.3945/ajcn.115.122317.
Rong Y et al. Egg consumption and risk of coronary heart disease and stroke: dose-response meta-analysis of prospective cohort studies. BMJ. 2013 (vol 346, e8539).