A Mediterranean‐style low‐glycemic‐load diet reduces the expression of HMG‐CoA reductase in mononuclear cells and correlates with decreases in insulin and LDL oxidation in women with metabolic syndrome

We recruited 25 women with metabolic syndrome (MetS) and elevated plasma LDL and instructed them to follow a Mediterranean‐style low‐glycemic‐load diet for 12 wk. Real‐time PCR was utilized to measure mRNA abundance of the LDL receptor (LDL‐r) and HMG‐CoA reductase (HMG‐CoA‐R) in mononuclear cells, which were used as a proxy of liver expression of these two genes. All women experienced favorable impacts on MetS variables, with decreases in waist circumference (p < 0.001), plasma triglycerides (p < 0.001) and blood pressure (p < 0.01). Also, participants had reductions in LDL‐C (p < 0.01), plasma insulin (p < 0.01) and oxidized LDL (oxLDL) (p < 0.01) over time. Although no changes in LDL‐r were observed, HMG‐CoA‐R gene expression was reduced (p < 0.05) after 12 wk. Significant correlations were found between HMG‐CoA‐R mRNA levels and plasma LDL‐C (r = 0.401, p < 0.05) and oxLDL (r = 0.645, p < 0.01). The reductions in plasma insulin (r = 0.570, p < 0.01) and insulin resistance as measured by HOMA (r = 0.443, p < 0.05) were also correlated with HMG‐CoA‐R mRNA levels. In conclusion, the observed reductions in plasma insulin may have affected the expression of this key regulatory gene of cholesterol synthesis. The reductions in HMG‐CoA‐R gene expression may be related to lower secretion of VLDL‐C, which in turn would account for the reductions in plasma LDL‐C and oxLDL [Supported by Metagenics, Inc, Gig Harbor, WA]