Featured article in the Fall 2015 Issue of Nutrition Close-Up; written by Jill Weisenberger, MS, RDN, CDE, FAND
The egg is one of those nutrient-dense foods that generates a lot of debate about its healthfulness. Because eggs are high in cholesterol, which has historically been linked to cardiovascular disease (CVD), healthcare professionals have long discouraged their patients from eating too many eggs. The warning to limit them, especially the cholesterol-rich yolk, is frequently delivered louder and stronger to people with diabetes because their risk of developing heart disease is quite high.
Recently the American Heart Association (AHA) and the American College of Cardiology stated that there was not enough evidence to confirm that dietary cholesterol increases low-density lipoprotein (LDL) cholesterol and CVD risk.1 On the heels of that acknowledgement, the Dietary Guidelines for Americans Committee recommended removing cholesterol as a nutrient of concern.2 These actions have registered dietitian nutritionists, diabetes educators and other healthcare professionals wondering if they can now fully embrace regular egg consumption for their patients with diabetes. To answer this question, I delved into the research. This is what I’ve learned.
Perhaps the earliest association between egg consumption and increased CVD risk among people with diabetes was found by Hu et al and published in 1999.3 They looked at nearly 120,000 men and women enrolled in the Nurses’ Health Study or the Health Professionals Follow-up Study. Using food frequency questionnaires at baseline and every two years, they classified egg consumption into five groups: less than 1, 1, 2-4, 5-6, 7 or more eggs per week. They found no association of egg intake and coronary heart disease (CHD) or stroke, except among the 5,309 subjects with diabetes. The researchers’ subgroup analysis showed that the consumption of at least seven eggs weekly doubled the risk of CHD among people with diabetes compared to those eating less than one egg weekly. Other researchers have addressed the link between eggs and CVD among people with diabetes. Some, but not all, have found an association.
In general, a limitation of population-based studies is the inability to determine cause and effect. Would the results differ if the researchers could account for more dietary factors? For example, on some plates, eggs keep company with wholesome fruit and whole-grain toast or oats. On other plates, eggs sit atop buttery biscuits and sausage gravy. Does the company eggs keep influence cardiovascular health? I would have to think so.
Several clinical trials show a different view of the health effects of eggs among people with diabetes or prediabetes. For example, researchers in Australia compared the effects of a weight maintenance diet containing two eggs daily for six days per week to a low-egg weight maintenance diet of similar protein content.4 Subjects in both groups replaced foods rich in saturated fats with those rich in unsaturated fats. After three months, there were no between-group differences for total cholesterol, LDL-cholesterol, triglycerides, glycemic control, waist circumference or blood pressure. The results of the 12-month data should be available within several months.
In a randomized crossover study, researchers compared the effects of an egg breakfast to an oatmeal breakfast.5 People with well-controlled type 2 diabetes consumed either one egg or ½-cup oatmeal as part of a balanced breakfast daily for five weeks. After a 3-week washout period, subjects switched to the other breakfast, which was similar in calorie and protein content. The researchers found no meal effect on glucose control, insulin levels or insulin resistance. Similarly, there were no significant differences in body weight, body fat, blood pressure, triglycerides, total cholesterol, LDL cholesterol, high-density lipoprotein (HDL) cholesterol, oxidized cholesterol or apolipoprotein B. However, tumor necrosis factor-alpha, a marker of inflammation, was significantly reduced following the egg period only. Interleukin-6 was borderline significant following the egg period, but there were no between-group differences in C- reactive protein.
Eggs offer solutions
Many of my patients present with several concerns that make eggs an ideal choice. Eggs are affordable and easy to prepare. Even my most cooking-challenged clients can scramble an egg. My older patients, especially, benefit from eggs’ lutein because the carotenoid may help protect their vision. Eggs are also easy to eat for those with chewing problems. They are nutrient-dense and full of protein and low in saturated fat. Most of my clients with diabetes are trying to manage their weight alongside their blood glucose. I encourage moderate amounts of protein at each of their three meals to help minimize muscle loss during weight loss.
There is much to learn about individual differences, however, including those with familial hypercholesterolemia. The prudent course is to closely monitor all CVD risk factors and make dietary changes as warranted.
In August, the American Diabetes Association and the AHA jointly released a scientific statement on the prevention of CVD among people with type 2 diabetes. These two organizations recommend any of several dietary patterns including the Dietary Approaches to Stop Hypertension (DASH) eating plan and a Mediterranean-style diet. They emphasize the importance of consuming a variety of wholesome foods. Given this scientific statement, my review of the research and my professional experience, I am very comfortable recommending eggs as part of a balanced diet rich in fruits, vegetables and other wholesome foods for my patients with diabetes.
Jill Weisenberger, MS, RDN, CDE, FAND is a registered dietitian nutritionist and certified diabetes educator with a master’s of science degree in food science and human nutrition. Her latest book, The Overworked Person’s Guide to Better Nutrition, offers solutions to everyday food and nutrition problems. Learn more at Jill’s website: www.jillweisenberger.com
- Stone NJ, Robinson J, Lichtenstein AH, et al. 2013 ACC/AHA Guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults. Circulation. 2014;129:S1-S45.
- United States Department of Agriculture. Scientific Report of the 2105 Dietary Guidelines Committee. February 2015. http://www.health.gov/dietaryguidelines/2015-scientific-report/PDFs/Scientific-Report-of-the-2015-Dietary-Guidelines-Advisory-Committee.pdf Accessed June 28, 2015.
- Hu FB, Stampfer MJ, Rimm EB, et al. A prospective study of egg consumption and risk of cardiovascular disease in men and women. JAMA. 1999;281:1387-1394.
- Fuller NR, Caterson, ID, Sainsbury Aet al. The effect of a high-egg diet on cardiovascular risk factors in people with type 2 diabetes: the Diabetes and Egg (DIABEGG) study-a 3-mo randomized controlled trial. Am J Clin Nutr. 2015;101:705-713.
- Ballesteros MN, Valenzuela F, Robles AE, et al. One egg per day improves inflammation when compared to an oatmeal-based breakfast without increasing other cardiometabolic risk factors in diabetic patients. Nutrients. 2015;7:3449-3463.
- In the context of a balanced, wholesome diet among people with type 2 diabetes, egg consumption may reduce inflammation and have little or no effect on lipid levels.
- Eggs are affordable, versatile, easy to prepare, and offer quality nutrition.