Apolipoprotein E levels in vegetarians.

Vegetarians are known to have low lipoprotein lipid and apolipoprotein Al and B levels. Since dietary cholesterol has recently been shown to have important effects on apolipoprotein E (apo E) metabolism, we measured plasma apo E levels in three groups of vegetarians. Group I (n = 36) consumed less than 10 mg cholesterol daily and 42% of calories as fat (P:S ratio 2.6). Group II (n = 10) and Group III (n = 18) consumed 97 and 179 mg cholesterol daily, and 35% of calories as fat (P:S ratios 0.7 and 0.9) respectively. Compared to control values, vegetarian plasma cholesterol and triglyceride levels were decreased by 10%-30% and 30%-55%. Plasma apo E levels were decreased equally in all groups by 35% (2.4 +/- 0.1 mg/dl versus 3.6 +/0 0.1 mg/kl, P less than .001). Plasma apo E levels were increased in parallel with lipid levels in pregnant vegetarians but were not different from non-lactating vegetarians in postpartum lactating women. Decreased apo E levels did not correlate with relative body weight, P:S ratio or intake of fat, carbohydrates or protein. Since all vegetarian diets studied were low cholesterol diets, decreased cholesterol intake may contribute to the low apo E levels. The apparent modification of apo E metabolism by vegetarian diets may be important in mediating effects of lipid lowering diets on atherogenesis.