An entertaining and informative perspective on eggs and health originally Tweeted by Dr. Stuart Phillips on May 1, 2015.
I can eat 50 eggs [pause] Nobody can eat 50 eggs! Its a classic scene (http://bit.ly/1QTeYlM) from a classic movie and if youve never seen Cool Hand Luke starring Paul Newman (among others) is a great film. But the point of my post is not to talk about eating 50 eggs (in an hour by the way), but about eggs and why they are an unnecessarily maligned superfood!
Of course they are often associated with cholesterol, saturated fat, and cardiovascular disease but is that so bad? Even the recent recommendations of the dietary guidelines committee http://1.usa.gov/1blg3BM now say what many already knew: Eggs and shrimp, nutrient-rich foods once vilified for their cholesterol content, are back on the menu now that scientific evidence shows only a weak link between dietary cholesterol and cholesterol levels in the blood. http://bit.ly/1IvhkUx (thats directly from Harvard magazine BTW so you can take that dietary advice to the bank ?? But theres still the tired old message to keep saturated fat below 10% but is that guidance still relevant?
A number of papers have called into question the idea that saturated fat causes/precipitates heart disease, the most notable of which is a meta-analysis by Siri-Tarino et al. [http://1.usa.gov/LzAh7O] in which they looked at data from 21 studies to derive relative risk for coronary heart disease (CHD), stroke, and cardiovascular disease (CVD). Heres what they found,
During 5-23 y of follow-up of 347,747 subjects, 11,006 developed CHD or stroke. Intake of saturated fat was not associated with an increased risk of CHD, stroke, or CVD. The pooled relative risk estimates that compared extreme quantiles of saturated fat intake were 1.07 (95% CI: 0.96, 1.19; P = 0.22) for CHD, 0.81 (95% CI: 0.62, 1.05; P = 0.11) for stroke, and 1.00 (95% CI: 0.89, 1.11; P = 0.95) for CVD. Consideration of age, sex, and study quality did not change the results.
And importantly, what they concluded,
A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.
Strange then that with each round of dietary guidance there is continuing pressure to reduce intake of saturated (solid) fats? OK, so what about eggs? Well the often demonized egg is, at least in my view, unfairly treated and several recent analyses and studies make my point. First, Ill move right to evidence-based medicine and use the meta-analysis by Rong et al., [http://1.usa.gov/1iQ7vl7] which (to cut to the chase) concluded,
The summary relative risk of coronary heart disease for an increase of one egg consumed per day was 0.99 (95% confidence interval 0.85 to 1.15; P=0.88 for linear trend) For stroke, the combined relative risk for an increase of one egg consumed per day was 0.91 (0.81 to 1.02; P=0.10 for linear trend) In a subgroup analysis of diabetic populations, the relative risk of coronary heart disease comparing the highest with the lowest egg consumption was 1.54 (1.14 to 2.09; P=0.01). In addition, people with higher egg consumption had a 25% (0.57 to 0.99; P=0.04) lower risk of developing hemorrhagic stroke.
The increased risk in diabetics is perhaps alarming, but a little murky. I say this because another study [http://1.usa.gov/1DOX9Ly] reached a dissimilar conclusion. In addition, there is work showing that increased egg consumption [http://1.usa.gov/1bJx5dk] reduces risk for development of T2D. A recent randomized trial the investigators, aimed to determine whether a high-egg diet (2 eggs/d for 6 d/wk) compared with a low-egg diet (<2 eggs/wk) affected circulating lipid profiles, in particular high-density lipoprotein (HDL) cholesterol, in overweight or obese people with prediabetes or T2D. Both groups were instructed to consume specific types and quantities of food to increase polyunsaturated (PUFA) and monounsaturated (MUFA) fat, in place of saturated fat. What they found was,
There was no significant difference in the change in HDL cholesterol from screening to 3 mo between groups; the mean difference (95% CI) between high- and low-egg groups was +0.02 mmol/L (-0.03, 0.08 mmol/L; P = 0.38). No between-group differences were shown for total cholesterol, low-density lipoprotein cholesterol, triglycerides, or glycemic control. Both groups were matched for protein intake, but the high-egg group reported less hunger and greater satiety post-breakfast http://1.usa.gov/1JWCTvr.
What I begin to see emerge with this research is that the egg is rather benign or likely beneficial food from a cardiometabolic perspective. So whats the upside? Eggs are very nutrient dense sources of protein for one. Each egg (including the yolk), boiled, provides 5 grams of fat,6 grams of protein, and only 77 calories and is highly satiating http://1.usa.gov/1EVu9rE and http://1.usa.gov/1C3JNfT (the latter study concluded cottage cheese does the same thing). In addition, eggs are sources of vitamins A, D, riboflavin, vitamin B12 and B6, folate, zinc, iron, lutein/zeaxanthin (a carotenoid that helps to maintain good vision and may help reduce the risk of age-related eye diseases, such as cataracts and macular degeneration), and choline. Finally, eggs contain all 9 indispensable amino acids and in a ratio that sets the gold standard for protein quality.
So while I might not recommend eating 50 eggs in an hour (thats almost 6 pounds of eggs in case youre interested) I think an egg or two per day is OK from a health, nutritional, and an economic (12 large eggs is still pretty inexpensive) standpoint. The much maligned egg deserves a break! Oh and they are damn tasty!!
And before someone asks no I didnt get paid (by anyone) to write this! But I do like eggs (Biased? Perhaps but arent we all?)
Stuart Phillips, Ph.D., is a Professor in the Exercise Metabolism Research Group at McMaster University.
Views expressed by the author may not be those of the Egg Nutrition Center.