Serum zinc and plasma lipoproteins in elderly women: Findings from the Nun Study

Supplementation with zinc has been associated with changes in lipoprotein levels in prior studies. The purpose of this study was to define further the relationship between serum zinc and plasma total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, and triglycerides. This study was conducted in a homogeneous population of elderly women who were not taking zinc supplements. Fasting blood samples were drawn from 87 women, 77-99 years old. Serum zinc concentrations were significantly positively correlated with total cholesterol (r = 0.37, P = < 0.01) and with LDL-cholesterol (r = 0.41, P = < 0.001). In 77-84-year-old women (N = 47), a normal serum zinc level (70-150 μg/dl) was associated with a 27 mg/dl higher mean LDL-cholesterol (P = 0.06) compared to low serum zinc (< 70 μg/dl). In 85-99-year-old women (N = 40), a normal serum zinc was associated with a 49 mg/dl higher mean LDL-cholesterol (P = 0.002) compared to low serum zinc. These associations were not materially affected by the potential confounding effects of weight, weight change over 8 years, triceps skinfold, or serum C-reactive protein. Overall, serum zinc concentration had a strong positive association with plasma LDL-cholesterol and to a lesser extent, with total plasma cholesterol in this population. The association between serum zinc and plasma cholesterol may be due to a third factor, such as red meat consumption, which is a significant source of zinc and saturated fat. Alternatively, zinc may play a role in cholesterol metabolism.