The Impact of Egg Limitations on Coronary Heart Disease Risk: Do the Numbers Add Up?

Abstract

For over 25 years eggs have been the icon for the fat, cholesterol and caloric excesses in the American diet, and the message to limit eggs to lower heart disease risk has been widely circulated. The “dietary cholesterol equals blood cholesterol” view is a standard of dietary recommendations, yet few consider whether the evidence justifies such restrictions. Over 50 years of cholesterol-feeding studies show that dietary cholesterol does have a small effect on plasma cholesterol concentrations. The 167 cholesterol feeding studies in over 3,500 subjects in the literature indicate that a 100 mg change in dietary cholesterol changes plasma total cholesterol by 2.2 mg/dL.

Today we recognize that dietary effects on plasma cholesterol must be viewed from effects on the atherogenic LDL cholesterol as well as anti-atherogenic HDL cholesterol since the ratio of LDL:HDL cholesterol is a major determinant of heart disease risk. Cholesterol feeding studies demonstrate that dietary cholesterol increases both LDL and HDL cholesterol with little change in the LDL:HDL ratio. Addition of 100 mg cholesterol per day to the diet increases total cholesterol with a 1.9 mg/dL increase in LDL cholesterol and a 0.4 mg/dL increase in HDL cholesterol. On average, the LDL:HDL ratio change per 100 mg/day change in dietary cholesterol is from 2.60 to 2.61, which would be predicted to have little effect on heart disease risk. These data help explain the epidemiological studies showing that dietary cholesterol is not related to coronary heart disease incidence or mortality across or within populations.

• eggs
• dietary cholesterol
• plasma cholesterol
• LDL
• HDL
• coronary heart disease

Key teaching points:

• Based on clinical feeding studies, the average change in plasma total cholesterol is 2.2 mg/dL per 100 mg/day change in dietary cholesterol.

• The plasma cholesterol response to a change in dietary cholesterol is independent of dietary fat type and amount and the baseline plasma cholesterol.

• The plasma lipoprotein cholesterol responses to a 100 mg/day change in dietary cholesterol average 1.9 mg/dL for LDL and 0.4 mg/dL for HDL cholesterol.

• Dietary cholesterol has little effect on the LDL:HDL cholesterol ratio.

Key teaching points:

• Based on clinical feeding studies, the average change in plasma total cholesterol is 2.2 mg/dL per 100 mg/day change in dietary cholesterol.

• The plasma cholesterol response to a change in dietary cholesterol is independent of dietary fat type and amount and the baseline plasma cholesterol.

• The plasma lipoprotein cholesterol responses to a 100 mg/day change in dietary cholesterol average 1.9 mg/dL for LDL and 0.4 mg/dL for HDL cholesterol.

• Dietary cholesterol has little effect on the LDL:HDL cholesterol ratio.

Notes

Dr. D.J. McNamara is the Executive Director of the Egg Nutrition Center, a health education and research center for the U.S. egg industry and a Vice-president of the United Egg Producers.

Presented, in part, at a meeting sponsored by the American Egg Board and Egg Nutrition Center held at Amelia Island, FL on February 25–27, 2000.