Read All About It: Get Your Vitamin D Now!
This may seem obvious but nutritional status reflects nutrient intakes. That is the message from a new research study. Choosing nutrient dense foods, those having more vitamins and minerals per serving or per 100 calories, or using dietary supplements is associated with better vitamin status. Eating enriched or fortified foods reduces the risk of inadequate nutrient intake among children and adolescents. In fact, the same can be said for everyone over 2y of age; dietary supplementation helps fill the nutrient gap left by diet.
So what is novel about this study? Vitamin D is exceptional in that we are not exclusively diet dependent. Skin makes vitamin D when exposed to sunlight. Sun exposure is limited by cold temperatures and culture, i.e. working indoors or clothing. Cheng and colleagues chose to identify the determinants of serum 25(OH)D concentrations, or vitamin D status, in 3,345 postmenopausal women participating in the Women’s Health Initiative Observational Status (WHI). Vitamin D intake explained less than 50% of the variance in serum 25(OH)D concentrations. Supplemental vitamin D use was positively correlated with serum vitamin D concentrations. More importantly, 11.8% of these women were vitamin D deficient (< 30 nmol/L) and 81.5% had suboptimal serum 25(OH)D levels (<75 nmol/L). Data from Figure 1 indicates that people did not achieve serum 25(OH)D levels of 75 nmol/L when taking 1000 IU vitamin D daily.
The study by Cheng and colleagues confirms that sun exposure and vitamin D supplements are important determinants of vitamin D status among postmenopausal women. In practice, the same relationship exists for premenopausal women, men, and children.
Cheng T-Y, Millen AE, Wactawaski-Wende J, Beresford SAA, LaCroix AZ, Zheng Y, Goodman GE, Thornquist MD, Neuhouser ML. Vitamin D intake determines vitamin D status of postmenopausal women, particularly those with limited sun exposure. 2014 J Nutr doi: 10.3945/jn.113.183541
Berner LA, Keast DR, Bailey RL, Dwyer JT. Fortified foods are major contributors to nutrient intakes in diets of US children and adolescents. 2014 JADA doi: 10.1016/j.jand.2013.10.012
Fulgoni III VL, Keast DR, Bailey RL, Dwyer J. Foods, fortificants, and supplements: Where do Americans get their nutrients? 2011 J Nutr doi:10.3945/jn.111.142257