25-hydroxyvitamin-d-2 and Weight-Loss

Low circulating concentrations of vitamin D metabolites have been associated with increased risk for several diseases and clinical conditions. Large observational studies and surveys have shown that obesity is independently associated with lower serum 25-hydroxyvitamin D (25(OH)D) concentration. Few studies have examined the effect of weight loss on serum 25(OH)D concentration. The purpose of this study was to prospectively examine the effect of weight loss on serum 25(OH)D concentration. Data were collected from 383 overweight or obese women who participated in a 2-year clinical trial of a weight-loss program, in which 51% (N = 195) lost at least 5% of baseline weight by 24 months, 18% (N = 67) lost 5-10%, and 33% (N = 128) lost >10%. Women who did not lose weight at 24 months had an increase in serum 25(OH)D of 1.9 (9.7) ng/ml (mean (SD)); 25(OH)D increased by 2.7 (9.1) ng/ml for those who lost 5-10% of baseline weight; and 25(OH)D increased by 5.0 (9.2) ng/ml for those who lost >10% of baseline weight (P = 0.014). At baseline, 51% (N = 197) of participants met or exceeded the recommended serum concentration of 20 ng/ml. By study end, 64% (N = 230) of overweight or obese women met this goal, as well as 83% (N = 20) of those whose weight loss achieved a normal BMI. These findings suggest that weight loss, presumably associated with a reduction in body fat, is associated with increased serum 25(OH)D concentration in overweight or obese women.

Topics: 25-Hydroxyvitamin D 2; Adult; Aged; Body Mass Index; Diet, Reducing; Exercise; Female; Humans; Middle Aged; Nutritional Status; Obesity; Prospective Studies; Vegetables; Weight Loss; Weight Reduction Programs

Obesity has been linked with poorer vitamin D status. The aim of this work was to analyze the changes in vitamin D status and body weight of 61 young, overweight/obese women following two different weight control programs. The study subjects were randomly assigned to one of two slightly hypocaloric diets: diet V, in which the consumption of greens and vegetables was increased, or diet C, in which the consumption of cereals (some of which were enriched with vitamin D) was increased. Dietary, anthropometric, and biochemical data were collected at the start of the study and at 2 weeks. At the beginning of the study, when taking into account only those women with a vitamin D intake below that recommended, obese women had a significantly lower mean serum 25(OH)D concentration than those who were lighter. Dietary intervention led to a greater reduction in energy intake among group C subjects; their weight was also that which was most reduced. In addition, the vitamin D intake and serum 25(OH)D values were increased only in group C women. Excess body weight was associated with deterioration in vitamin D status, especially when the intake of this vitamin was lower than that recommended. Subjects with higher serum vitamin D at the beginning of the study lost more weight than those subjects with lower initial values. Diet C was associated with a greater weight loss than diet V, and led to a greater increase in vitamin D intake and serum 25(OH)D levels. This might be of interest in the improvement of health in people trying to lose weight.

Topics: 25-Hydroxyvitamin D 2; Adult; Body Mass Index; Diet Records; Diet, Reducing; Edible Grain; Female; Food, Fortified; Humans; Nutrition Policy; Nutritional Status; Obesity; Overweight; Vegetables; Vitamin D; Weight Loss; Young Adult

A significant relationship between body weight (BW) and bone mass (BM) has been established previously. A diet-induced weight loss is accompanied by a significant decrease in bone mineral density (BMD) and total body bone mineral (TBBM), but the underlying mechanisms are not clarified. Sixty-two obese women were included in the study. Dual-energy X-ray absorptiometry (DXA) and measurements of a series of calcium-regulating hormones and biochemical markers of bone turnover were performed at baseline and after 1 month and 3 months on a low calorie diet. Thirty of the women were randomized to a daily supplement of 1 g of calcium. After an additional 3 months without dietary prescriptions or calcium supplements, a subgroup of 48 subjects (24 from each group) were scanned again using DXA. There was a significant decrease in TBBM after 1 month and 3 months. A similar pattern was observed in the bone mineral content (BMC) of the lumbar spine in the patients who did not receive a calcium supplement, whereas no changes occurred in the supplemented group. The initial calcium supplementation seemed to protect against bone loss in the lumbar spine but not in the TBBM. In the nonsupplemented group, a statistically significant inverse correlation was found between the calcium/creatinine ratio in the morning urine and the changes in BMC of the lumbar spine. Such a relationship was not seen in the calcium-supplemented group. In the nonsupplemented group, no significant biochemical changes were observed, whereas a significant decrease in serum parathyroid hormone (PTH) was seen in the calcium-supplemented group. This might explain some of the protective effects of calcium supplementation on trabecular bone mass. We conclude that a diet-induced weight loss is accompanied by a generalized bone loss, which probably is explained mainly by a reduced mechanical strain on the skeleton. This loss can be partly inhibited by a high calcium intake. Therefore, a calcium supplementation should be recommended during weight loss, even if the diet contains the officially recommended amounts of calcium.

Topics: 25-Hydroxyvitamin D 2; Amino Acids; Body Mass Index; Bone Density; Calcitriol; Calcium; Creatinine; Diet; Dietary Supplements; Female; Hip Joint; Humans; Lumbar Vertebrae; Obesity; Osteocalcin; Random Allocation; Weight Loss