Vitamin D Screening Provides Valuable Information
If you live in the US and have just celebrated Thanksgiving, it is quite possible your waistband feels a tad tighter this Monday. You should also know that increased visceral fat may increase your need for vitamin D supplementation. And shortening daylength in the northern hemisphere isn’t any help.
Zhang and colleagues randomly selected 1,105 adults living in China. Visceral fat accumulation and serum vitamin D concentrations were measured. Men and pre-menopausal women carrying extra visceral fat were more likely to have serum 25(OH)D3 concentrations below 30 µg/L (75 nmol/L, insufficient) and 20 µg/L (50 nmol/L, deficient). Men with the most abdominal fat were 4.9-fold more likely to be vitamin D insufficient and deficient than their leanest counterparts. For pre-menopausal women, the risk was 1.8-fold.
This study demonstrates the importance of measuring nutritional status. Because vitamin D is fat-soluble, individuals carrying extra visceral fat may need to consume more vitamin D to maintain sufficient serum 25(OH)D3 concentrations.
When it comes to maintaining a healthy body weight, or weight loss, it is important to remember that good nutrition involves more than just calorie counting. Limiting the intake of essential nutrients can be unhealthy. Indeed, low blood vitamin D concentrations may increase the risk of cardiovascular disease.
Central adiposity is associated with lower blood 25(OH)D3 concentrations and insulin resistance in overweight and obese individuals. As a nutrition scientist, I could advocate for the NIH to conduct research into the vitamin D requirements of overweight and obese individuals. Then I could lobby for the Institute of Medicine to obtain funds to establish an expert committee which would determine the Estimated Average Intake (EAR) and Recommended Dietary Allowance (RDA) for overweight and obese individuals. Unfortunately, that would take years.
Instead, contrary to others, my desired option is for everyone to get their blood vitamin D status measured annually. With this information, through thick or thin, we would know if our vitamin D concentrations were sufficient, insufficient or deficient and could adapt our behavior (hours in the sunshine) or dietary intake.
Zhang M, Li P, Zhu Y, Chang H, Wang X, Liu W, Zhang Y, Huang G. Higher visceral fat area increases the risk of vitamin D insufficiency and deficiency in Chinese adults. 2015 Nutr Metab doi: 10.1186/s12986-015-0046-x
Wright CS, Weinheimer-Haus EM, Fleet JC, Peacock M, Campbell WW. The apparent relationship between plasma 25-hydroxyvitamin D and insulin resistance is largely attributable to central adiposity in overweight and obese adults. 2015 J Nutr doi: 10.3945/jn.115.220541
Gangloff A, Bergeron J, Pelletier-Beaumont E, Nazare J-A, Smith J, Borel A-L, Lemieux I, Tremblay A, Poirier P, Almeras N, Despres J-P. Effect of adipose tissue volume loss on circulating 25-hydroxyvitamin D levels: results from a 1-year lifestyle intervention in viscerally obese men. 2015 Int J Obes doi: 10.1038/ijo.2015.118