Reduced LDL particle size in children consuming a very-low-fat diet is related to parental LDL-subclass patterns

Background: A genetically influenced atherogenic lipoprotein phenotype char acterized by a predominance of small, dense LDL particles (subclass pattern B) can be induced by low-fat diets in healthy subjects with large LDL part icles (pattern A). Objective: The aim of this study was to test whether genetic predisposition to subclass pattern B contributes to susceptibility to induction of this t rait by a low-fat diet. Design: The prevalence of pattern B in children is relatively low compared with that in older individuals, but genetic susceptibility to this trait in offspring can be inferred by its presence in their parents. Plasma lipopro teins were analyzed 10 d after a change from a usual diet to a very-low-fat (10% fat), high-carbohydrate diet in offspring (mean age. 14 y; range: 7-2 8 y) of 22 families according to parental LDL-subclass patterns when consum ing a low-fat diet: AXA mating (9 families with 19 children), AXE mating (5 families with 10 children), and BXB mating (8 families with 21 children). Results: The very-low-fat, high-carbohydrate diet produced significantly gr eater decreases in LDL particle size in offspring of BXB parents ((x) over bar +/- SE: -0.55 +/- 0.16 nm) and AXE parents (-0.48 +/- 0.19 nm) than in offspring of AxA parents (0.14 +/- 0.20 nm). The number of children express ing pattern B with the 10%-fat diet and the proportion of children converti ng from pattern A to pattern B was significantly greater in offspring of BX B parents than in those with I or 2 pattern A parents. Conclusion: A very-low-fat, high-carbohydrate diet can induce expression of LDL-subclass pattern B in genetically predisposed children with low expres sion of the trait while consuming their usual diets.