The 2010 Dietary Guidelines for Americans (1) recommended limiting dietary cholesterol and specifically egg consumption for individuals with type 2 diabetes (T2D). The recommendation was based on epidemiology studies reporting positive statistical association of increased cardiovascular disease (CVD) risk for individuals with T2D who consumed 7 or more eggs each week. While the Dietary Guideline Committee cited the concern about egg consumption for T2D, they acknowledged that the relationship was a statistical association with no proof of cause or mechanism and emphasized the need for more research.
Shortly after the Dietary Guidelines were presented, Drs. Mozaffarian and Ludwig at Harvard wrote a commentary arguing that the focus of the Dietary Guidelines on single nutrients or single foods was inadequate and misleading for evaluation of modern diverse diets. They argued Dietary Guidelines must consider the context of foods within food patterns and lifestyles to define health risks (2).
Recent Published Studies
A recent paper from Spain evaluating the Mediterranean diet emphasizes this point (3). These investigators specifically evaluated the relationship of egg consumption to diabetes risk in a cohort of adults following a Mediterranean diet pattern. They found no relationship of egg consumption (or cholesterol intake) with T2D risk suggesting that eggs were not a risk factor when consumed within a healthy dietary lifestyle.
Still, contrary to this report, a meta-analysis published in the British Medical Journal (4) evaluated 16 prospective cohort studies that specifically examined relationships of egg consumption with incidence of T2D and CVD and found a positive Risk Ratio (RR) of 1.54 for egg consumption with CVD within the population of T2D.
If you’re not used to thinking about RR, a RR of 1.0 means there is no association, and for comparison, a 50-year old smoking a pack per day has a RR of over 20 for lung cancer. So the true risk of heart disease in a 50-year old male with normal blood lipids and normal blood pressure is about 2% and a RR of 1.54 would increase the risk to 3%.
Perhaps more important than the potential small risk in T2D, these investigators found no association of egg intake with risk of CVD or stroke in non-diabetic adults with the RR less than 1.0 suggesting that greater egg intake reduced risk of both CVD and stroke. Further, they found a RR of 0.75 for egg consumption and stroke in adults with T2D.
Concerns about egg consumption by individuals with T2D remains a question that requires better research to determine if the risk is a true relationship to eggs or if it is a guilt by association with other aspects of overall diet quality. This would include dietary intakes such as total fat, types of fat, dietary fiber, green vegetables or fruit.
What should not be lost within the debate about diabetes is that study after study shows there is no association
of egg consumption with CVD risk in non-diabetic adults and that egg consumption reduces risk for stroke in both diabetic and non-diabetic adults.
1. U.S. Department of Health and Human Services. Dietary Guidelines for Americans. http:/www.health.gov/dietaryguidelines/ Part D, Section 3.
2. Mozaffarian D, Ludwig DS. Dietary Guidelines in the 21st Century a Time for Food. JAMA 304:681, 2010.
3. Zazpe I, Beunza JJ, et al. Egg consumption and risk of type 2 diabetes in a Mediterranean cohort: the SUN project. Nutr Hosp 28:105, 2013.
4. Rong Y, Chen L, et al. Egg consumption and risk of coronary heart disease and stroke: dose-response meta-analysis of prospective cohort studies. BMJ 2013 (doi: 10.1136/bmj.e8539).