Effect of Treating Vitamin D Deficiency on Glucose Homeostasis and Metabolic Markers in Apparently Healthy, Young or Aged, Normal-weight or Obese Lebanese People

A low serum 25-hydroxyvitamin D (25(OH)D) concentration has been shown to correlate with higher fasting blood glucose (FBG) and insulin levels and other metabolic abnormalities like dyslipidemia. Previous studies suggest that vitamin D supplementation is able to improve insulin sensitivity and metabolic markers. The aim of the study was to investigate the effect of vitamin D supplementation on glucose homeostasis and metabolic markers in healthy normal weight and overweight young subjects and healthy normal-weight and overweight elderly subjects living in Beirut, Lebanon. Participants (n= 180; 93 men and 87 women) deficient in vitamin D were recruited from Saint Charles Hospital, Beirut, Lebanon. Four groups were recruited: normal-weight adults (n=30, age ≤ 65 years and BMI < 25 kg/m²), overweight adults (n=30, age ≤ 65 years and BMI ≥ 25 kg/m²), normal-weight elderly (n=60, age ≥ 65 years and BMI < 25 kg/m²) and overweight elderly (n=60, age ≥ 65 years and BMI ≥ 25 kg/m²).

Participants received a supplement of 10,000 IU cholecalciferol to be taken three times per week for a period of 6 months. Glucose homeostasis and metabolic markers were measured at start of treatment, at 3 months and at 6 months.