There have been hundreds of studies on the effect cholesterol has on human coronary problems. The conclusions of some studies have been partly responsible for a decline in the consumption of eggs, leading to hard times the past two years for egg producers.
A more optimistic study has just been released by D.P. Cornforth, a professor of nutrition and food science in Utah State University's Department of Nutrition and Food Science, and B.N. Dobson, a graduate student. The paper is titled "A Review of the Effects of Egg Consumption on Blood Cholesterol and Coronary Heart Disease."The report was provided by Donald C. Dobson, a poultry specialist for USU's Extension Service, who said neither man has any financial interest in the poultry industry.
B.N. Dobson and Cornforth concluded, "Dietary cholesterol has little relation to blood cholesterol for normal individuals on a balanced diet that includes fiber-rich foods. Those few individuals who are sensitive to dietary cholesterol level need to be identified, and their diet modified accordingly."
Cornforth and B.N. Dobson said cholesterol is an important component of an egg yolk because it is needed for proper development of the young chick. It also is needed for proper development of the nervous system, where it is a part of the insulating sheath of nerve and brain cells.
"High blood cholesterol levels are definitely associated with higher incidence of coronary heart disease. This is especially apparent in those individuals who, due to hereditary factors, are unable to remove cholesterol from the blood," Dobson and Cornforth wrote.
They said a cause and effect relationship between diet composition and heart disease is lacking. Total caloric intake and obesity are likely the important factors, rather than the level of saturated fat or cholesterol.
"In fact, several epidemiologic studies have failed to show a significant relationship between cholesterol intake and blood cholesterol levels," their study said.
They said several studies have shown that changing a person's diet to include four eggs per day didn't significantly increase blood cholesterol levels. They said a person who hadn't eaten eggs and suddenly started eating them would have an increase in blood cholesterol levels higher than a person who had eaten eggs regularly and suddenly ate more than usual.
Cholesterol problems are related to the way it is introduced into the diet, the two men said. "Purified cholesterol or cholesterol added as dried egg powder usually will cause an increase in blood cholesterol, particularly if the diet is low in fiber."
B.N. Dobson and Cornforth said added cholesterol in the diet doesn't increase blood cholesterol in diets containing soluble fiber. One study found that cholesterol added to a diet of meat and bread caused no increase in blood cholesterol in rats, but blood cholesterol did increase in rats fed purified fiber diets, they said.
Recommendations of the American Heart Association that all Americans limit consumption of cholesterol to less than 300 milligrams per day aren't supported by a concensus of scientists working in this area. That recommendation would eliminate eggs from the diet since an average egg contains between 240 and 260 milligrams of cholesterol.
They concluded, "Recommendations concerning dietary cholesterol are not warranted for the general population. For the general public, the dietary recommendation to eat a balanced diet and avoid eating excess total calories is sufficient to ensure a healthy population."