A correlation study between serum zinc and plasma total cholesterol, high density and low density lipoprotein cholesterol in thyroid dysfunction

Diseases of thyroid gland can affect nearly every function of our body. Thyroid hormone binding transcription factors, which are essential for modulation of gene expression, contain zinc bound to cysteine residues and also thyroid hormones influence zinc metabolism by affecting zinc absorption and excretion. Zinc is required for enzymes involved in lipid synthesis and lipoprotein excretion. Zinc is also known to have lipid lowering action. Effect of alteration of zinc on total cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol is still not clear with variable views. 61 subjects were divided into three groups of 19 hyperthyroid, 20 hypothyroid and 22 euthyroid who visited Kasturba Hospital, Manipal. The serum zinc correlated strongly negative and significantly with total cholesterol (r= -0.564), high density lipoprotein (r= -0.548) and low density lipoprotein cholesterol (r= -0.566) in hyperthyroid group. But the correlation in hypothyroid and euthyroid group differed and was not significant. Our study demonstrated a significant relationship and hence effect of serum zinc on total cholesterol, high density lipoprotein and low density lipoprotein cholesterol in hyperthyroid subjects but not on other groups. Elevated levels of total cholesterol and low density lipoprotein cholesterol may be proatherogenic and increase the risk of cardio vascular diseases hence zinc can be an important supplement during treatment of dyslipidaemia in thyroid abnormalities.