Many health professionals and consumers have upon occasion admitted to me that they thought “the egg got a bad rap” during the 1980s and 90s, when eggs were seen as an icon for dietary and serum cholesterol. They are often proud to say that they personally defied common wisdom by continuing to consume eggs. As scientific technology improved and confounding variables were better controlled, scientific findings and dietary guidance moved away from looking at egg intake as a risk factor and now focuses on the many nutritional benefits of consuming eggs. However, one curious association has continued to plague the egg. Epidemiological findings have shown, at times, an association between egg intake and cardiovascular disease in the diabetic population. No mechanism has been identified to explain this association however, the fact that eggs are often accompanied by a high saturated fat, high refined carbohydrate and sedentary lifestyle may have made egg intake in this population an artifact or marker of poorly controlled diabetes.
Fortunately, a recently published study in the British Journal of Nutrition by Pearce, Clifton and Noakes (Br J Nutr, Feb 2011, 105(4):584-92) attempted to assess the effect of egg intake on biomarkers of cardiovascular disease in free living overweight diabetic adults who have been instructed to eat a high protein, calorie restricted diet with either 2 eggs a day or a substitute source of animal protein. Sixty five subjects, average age of 60 years completed the 12 week study. All consumed 1400 calories/d with a macronutrient distribution of 40% carbohydrate, 30% protein, 30% fat. Subjects were allowed to continue taking diabetic and lipid lowering medication as prescribed by their physician. The treatment group received 2 eggs/day with an average cholesterol intake of 590mg of cholesterol while the control group received a similar quantity of protein from chicken, meat or fish without eggs and an average cholesterol intake of 214mg/day.
As one would expect, both groups that consumed a high protein, calorie restricted diet, lost an average of about 6 kg or 13 pounds. The key finding was that a diet high in dietary cholesterol from eggs did not adversely affect blood lipids or cardiovascular disease risk in adults with type 2 diabetes. In fact, a diet high in dietary cholesterol from eggs improved several biomarkers of health including increased blood levels of HDL, lutein and folate more effectively than the isoenergetic diet which included alternative animal sources of protein. The authors conclude “These results suggest that a high protein energy restricted diet high in cholesterol from eggs may have nutritional benefits and assist in metabolic control in individuals with type 2 diabetes.” Many of us knew it all along.
