Effect of interaction between PPARG, PPARA and ADIPOQ gene variants and dietary fatty acids on plasma lipid profile and adiponectin concentration in a large intervention study

Unsaturated fatty acids are ligands of PPAR-γ, which up-regulates genes involved in fatty acid transport and TAG synthesis and the insulin-sensitising adipokine adiponectin, which activates fatty acid β-oxidation via PPAR-α action in liver. We investigated the effect of dietary fatty acid interaction with PPARG, PPARA and ADIPOQ gene variants on plasma lipid and adiponectin concentrations in the Reading Imperial Surrey Cambridge King's study, a five-centre, parallel design, randomised controlled trial of 466 subjects at increased cardiometabolic risk. After a 4-week run-in to baseline, SFA was replaced by MUFA or carbohydrate (low fat) in isoenergetic diets for 24 weeks. Habitual dietary PUFA:SFA ratio×PPARG Pro12Ala genotype interaction influenced plasma total cholesterol (P=0·02), LDL-cholesterol (P=0·002) and TAG (P=0·02) concentrations in White subjects. PPARA Val162Leu×PPARG Pro12Ala genotype interaction influenced total cholesterol (P=0·04) and TAG (P=0·03) concentrations at baseline. After high-MUFA and low-fat diets, total cholesterol and LDL-cholesterol were reduced (P<0·001) and gene×gene interaction determined LDL-cholesterol (P=0·003) and small dense LDL as a proportion of LDL (P=0·012). At baseline, ADIPOQ -10066 G/A A-allele was associated with lower serum adiponectin (n 360; P=0·03) in White subjects. After the high-MUFA diet, serum adiponectin increased in GG subjects and decreased in A-allele carriers (P=0·006 for difference). In GG, adiponectin increased with age after the high MUFA and decreased after the low-fat diet (P=0·003 for difference at 60 years). In conclusion, in Whites, high dietary PUFA:SFA would help to reduce plasma cholesterol and TAG in PPARG Ala12 carriers. In ADIPOQ -10066 GG homozygotes, a high-MUFA diet may help to increase adiponectin with advancing age.