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 characterized by a predominance of small, dense LDL particles (subclass pattern B) can be induced by low-fat diets in healthy subjects with large LDL particles (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 trait 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 lipoproteins 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: 7-28 y) of 22 families according to parental LDL-subclass patterns when consuming a low-fat diet: AXA mating (9 families with 19 children), A×B mating (5 families with 10 children), and BXB mating (8 families with 21 children). Results: The very-low-fat, high-carbohydrate diet produced significantly greater decreases in LDL particle size in offspring of BXB parents (x ± SE: -0.55 ± 0.16 nm) and AXB parents (-0.48 ± 0.19 nm) than in offspring of AXA parents (0.14 ± 0.20 nm). The number of children expressing pattern B with the 10%-fat diet and the proportion of children converting from pattern A to pattern B was significantly greater in offspring of BXB parents than in those with 1 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 expression of the trait while consuming their usual diets.