Issues of dysnutrition have replaced issues of malnutrition in the new millennium. Vitamin D has become the subject of much concern due to the recognition of the increased role Vitamin D plays in the functioning and well-being of our bodies. Information gleaned from recent medical studies links insufficient and deficient levels of Vitamin D to increased risk of cardiovascular disease, insulin resistance diabetes, impaired balance, osteoporosis, cognitive impairment and a possible increased risk of cancers such as breast, colon and prostate.
Defined ranges for insufficient and deficient Vitamin D levels have not been established for broad usage. Optimal ranges for serum 25(OH)D, which is the best indicator of Vitamin D status, vary from 16 to 48 ng/mL.
Changes in body composition adversely impact health and a variety of metabolic parameters in the clinically obese population. Vitamin D is not readily available to the body from food sources and exposure to direct sunlight when excess body fat is present.
Minimally Invasive Surgeons of Texas (MIST), which is part of The University of Texas Health Science Center at Houston (UTHealth) Medical School’s Department of Surgery, conducted a pilot study. Height, weight and serum 25(OH)D levels were prospectively collected on 100 subjects with a body mass index (BMI) > 30 mg/kg2 which reflects obesity as defined by the National Heart Lung and Blood Institute. Vitamin D insufficiency/deficiency was defined as a serum 25(OH)D level < 35 ng/mL for this study. An insufficient/deficient Vitamin D level was detected in 96 subjects. This cohort of subjects demonstrated an inverse relationship between BMI and serum 25(OH)D levels. Initial evidence from this small sample size points to an increased risk of Vitamin D insufficiency/deficiency as BMI increases into the 40s, 50s and 60s due to a decrease in the bioavailability of Vitamin D.
Serum 25(OH)D levels are not routinely assessed by medical care providers. The results from this pilot study point to the need for evaluation of serum 25(OH)D levels in a larger group of adults with a BMI > 30 mg/kg2 due to the decay in Vitamin D levels as BMI increases.