Vitamin D: Supporting Growth and Development of Future Generations
With two adult sons, I hope to become a grandparent someday. Because our sons live further north (Canada), today’s research study has me reflecting upon vitamin D recommendations. Over 100 years ago, scientists knew the bones of rachitic children had abnormally low bone mineral density, administering calcium did not prevent the condition, and the disease occurred primarily in large cities (with pollution from burning coal) in northern latitudes.
Using a cross-sectional analysis from the healthy New Nordic Diet (OPUS) School Meal Study, Petersen and colleagues examined vitamin D status of 782 Danish children (8-11y). Only 2-4% of children had deficient serum 25(OH)D3 concentrations. Based on visual observations, i.e. a lack of rickets, and population statistics, Danish parents can be comforted that their children are at low risk of vitamin D deficiency. Is this enough? To avoid deficiency?
Don’t we want to give children more than to avoid vitamin D deficiency? Who doesn’t want to give them every advantage to be strong, smart, and healthy? Serum 25(OH)D3 concentrations ≤ 50 nmol/L are inadequate. The Institute of Medicine has determined this. Today, we learn from the OPUS study that 28% of Danish children have vitamin D concentrations below recommended levels. As a parent, grandparent, or caregiver, you simply cannot know their vitamin D status without a serum 25(OH)D3 measurement.
The food industry is accused of over-fortifying foods and indiscriminately recommending dietary supplements. This is amazing to me. Beyond comprehension. Fortified foods have nearly eradicated many nutritional deficiencies. Research in countries where dietary supplementation is prevalent finds only a small percentage of children exceeding dietary upper limits (ULs).
Nevertheless, the accusations have a basis. Why? Because it is impossible to provide appropriate nutritional guidance without measuring biological markers of nutritional status. Just like physicians send patients for laboratory tests before prescribing medications to manage blood glucose and cholesterol concentrations, we should be aware of our serum vitamin D concentrations during the darkest part of the year.
As a nutritionist, what will I advise my sons when they have children? Number one: have my grandchild’s serum 25(OH)D3 levels measured to guide us. Second: encourage consumption of foods rich in vitamin D3 knowing that the biggest influencers of vitamin D status are: moderate-to-vigorous physical activity, outdoor walking during school hours, and taking vitamin D-containing supplements ≥3d per week.
Petersen RA, Damsgaard CT, Dalskov S-M, Sorensen LB, Hjorth MF, Ritz C, Kjolbaek L, Andersen R, Tetens I, Krarup H, Astrup A, Michaelsen KF, Molgaard C. Vitamin D status and its determinants during autumn in children at northern latitudes: a cross-sectional analysis from the optimal well-being, development and health for Danish children through a healthy New Nordic Diet (OPUS) School Meal Study. 2015 Br J Nutr doi: 10.1017/S0007114511351500433X
Carpenter KJ, Zhao L. Forgotten mysteries in the early history of vitamin D. 1999 J Nutr 129:923-927
Sacco JE, Tarasuk V. Health Canada’s proposed discretionary fortification policy is misaligned with the nutritional needs of Canadians. 2012 J Nutr doi: 10.3945/jn.109.109637
Bakwin H. The overuse of vitamins in children. 1961 J Ped 59(1):154-161
Dwyer JT, Woteki C, Bailey R, Britten P, Carriquiry A, Gaine PC, Miller D, Murphy MM, Smith-Edge M. Fortification: new findings and implications. 2014 Nutr Rev doi: 10.1111/nutre.12086
Wallace TC, McBurney M, Fulgoni III VL. Multivitamin/mineral supplement contribution to micronutrient intakes in the United States, 2007-2010. 2014 JACN doi: 10.1080/07315724.2013.846806