Effect of High and Low Doses of Vitamin D on Insulin Resistance in Healthy Women

Vitamin D has been traditionally involved in regulation of bone homeostasis. However, vitamin D has also been linked clinically to various diseases including metabolic syndrome. The aim of this study was to examine the effect of low and high doses of vitamin D supplement on serum level of vitamin D and insulin resistance. A total of 120 females were recruited in this study and supplemented weekly with 25,000 IU vitamin D or 50.000 IU vitamin D for three months. Anthropometric measurements were measured at the beginning of the study. Blood samples were collected at the beginning of the study to determine the baseline of the clinical variables and collecting again after three months. Insulin resistance was measured using HOMA-IR. After vitamin D supplement, a significant increase observed in serum levels of vitamin D in group treated with low dose of vitamin D (LDVD) and highly significant increase in group treated with high dose of vitamin D (HDVD). In a group treated with higher dose (HDVD), a significant improve in insulin sensitives was observed. High dose of vitamin D (50,000 IU) is more effective in both correcting blood level of vitamin D and improving the sensitivity of insulin.