Background: The inherited apolipoprotein E (apoE) phenotype may determine effectiveness of dietary atherosclerosis prevention. This study analyzes the effects of apoE phenotypes on changes in serum lipid concentrations in a 6-month prospective, randomized trial of a low-saturated-fat, low-cholesterol diet in infancy.
Patients and methods: One thousand sixty-two healthy infants were randomized to intervention and control groups at the age of 7 months. Counseling was provided to the intervention families when the children's ages were 7, 8, and 10 months. Dietary goals were the child's intake of energy ad libitum, fat at 30% to 35% of energy, cholesterol at less than 200 mg/d, and saturated, monounsaturated, and polyunsaturated fatty acids at a 1:1:1 ratio. Control families consumed an unrestricted diet. The apoE phenotype of 846 of the infants was determined; serum lipid and lipoprotein concentrations were measured at 7 and 13 months of age; and nutrient intakes were analyzed using 3-day food records at 8 and 13 months of age.
Results: At 7 months of age, serum cholesterol concentration was higher in apoE4-positive infants (E2/E4, E3/E4, and homozygous E4) than in apoE4-negative infants (159 +/- 31 mg/dL [4.10 +/- 0.81 mmol/L] vs 150 +/- 29 mg/dL [3.89 +/- 0.74 mmol/L]). The high-density lipoprotein cholesterol concentration was slightly lower in apoE4-positive infants than in apoE4-negative infants (34 +/- 8 mg/dL [0.88 +/- 0.20 mmol/L] vs 35 +/- 7 mg/dL [0.91 +/- 0.19 mmol/L]). Between 7 and 13 months of age, the serum cholesterol concentration in infants in the intervention group was unchanged, apoB concentration increased slightly, and apoA1 concentration decreased. In the control infants, serum cholesterol concentration increased 9 +/- 25 mg/dL (0.24 +/- 0.65 mmol/L), apoB concentration increased markedly, and apoA1 concentration was stable. Changes in serum lipid and apo concentrations that resulted from the dietary intervention were independent of the apoE phenotype.
Conclusions: The apoE phenotype influenced serum cholesterol concentration markedly by 7 months of age. Between the ages of 7 and 13 months, a reduced saturated fat and cholesterol diet effectively prevented the age-associated increases in serum cholesterol and non-high-density cholesterol concentrations that were obvious in the control infants. The effects of the diet occurred in the infants independently of the apoE phenotype.