American Journal of Clinical Nutrition, Vol 17, 296-304, Copyright © 1965 by The American Society for Clinical Nutrition, Inc.

Influence of the Nature of the Fat in Diets High in Carbohydrate (Mainly Derived from Bread) on the Serum Cholesterol

¹ From the Department of Medicine A, Hadassah Hebrew University Hospital and Medical School, Jerusalem, Israel

After a control period on a so-called "western" type of diet, two groups of healthy volunteer subjects consumed a diet high in carbohydrate (62 calories per cent) and relatively low in fat (21 calories per cent); most of the carbohydrates and a large part of the protein were derived from bread (which furnished 54 per cent of the calories); the amount of sugar was very low. In one group (group A), the fat was derived almost entirely from safflower oil; in the other (group B), from butter.

The average serum cholesterol level fell considerably in both groups. The decrease was greatest in group A, but the difference between the two groups was small compared to the large decrease in both. When the diets were interchanged in the groups, the cholesterol levels "crossed" but remained lower in both than during the control period. There were no significant changes during the next period of the experiment in which the total caloric content was restricted by decreasing the amount of bread allowed.

The results indicate that the nature of the fatty acids in the diet has only a relatively small effect on serum cholesterol when the total intake of fat is low. These results also explain why serum cholesterol levels in certain eastern populations, such as the Yemenites, are low: although the fat they eat is mainly derived from meat and milk, the amount of total (and thereby also of saturated) fatty acids in their diet is small. In how far the large quantity of bread in the diet of many middle-eastern population groups is also more directly responsible for their low average serum cholesterol levels remains to be investigated.