Is Vitamin D Deficiency Making Kids Fat?

A new research study published in the American Journal of Clinical Nutrition [1] looked at the association between vitamin D levels and adiposity in children.  Previous research has shown that serum levels of vitamin D are inversely associated with obesity in adults.

Researchers supported in part by the Harvard Clinical Nutrition Research Center investigated the association between vitamin D serostatus and BMI (Body Mass Index), waist-circumference, skinfold thickness ratio, and height in children from Bogota Columbia.

The study itself included 479 school age children who were followed in this longitudinal study for a median duration of 30 months.

What did the researchers find?  To start with, they found that there was a modest greater  annual increase in BMI of 0.1/year in vitamin D deficient children compared to those who were not deficient.  Though this represents a modest increase in BMI, keep in mind that this number represents an annual figure that compounds over time.

The Study Authors Concluded:

Vitamin D serostatus was inversely associated with the development of adiposity in school-age children.

Vitamin D2 vs. Vitamin D3

If you’ve ever gone to a health food store or pharmacy to buy Vitamin D, you have have noticed that you have two choices available—vitamin D2 or vitamin D3 supplements.  Both are inactive forms of vitamin D that get either stored as 25, hydroxyvitamin D (inactive storage form) or converted to the tightly-controlled active form 1,25 hydroxyvitamin D by your liver and kidneys.  As some added background, vitamin D3 or cholecalciferol is the form produced by your skin in response to UV radiation.

A new study published in the Clinical Journal of Endocrinology and Metabolism [2] further sheds some light on resolving the differences between the two commercially available forms of this vitamin.  Also keep in mind that the recommendations for Vitamin D intake were recently increased.

A total of 33 healthy adults were randomized to receive either vitamin D2 or vitamin D3 at a dose of 50,000 IU/week for 12 weeks.

Vitamin D3 Is More Potent:

“D3 is approximately 87% more potent in raising and maintaining serum 25(OH)D concentrations and produces 2- to 3-fold greater storage of vitamin D than does equimolar D2. For neither was there evidence of sequestration in fat, as had been postulated for doses in this range.”

They Concluded:

“Given its greater potency and lower cost, D3 should be the preferred treatment option when correcting vitamin D deficiency.”


  1. Gilbert-Diamond D, Baylin A, Mora-Plazas M, Marin C, Arsenault JE, Hughes MD, Willett WC, Villamor E. Vitamin D deficiency and anthropometric indicators of adiposity in school-age children: a prospective study. Am J Clin Nutr. 2010 Dec;92(6):1446-51. Epub 2010 Oct 6.
  2. Heaney RP, Recker RR, Grote J, Horst RL, Armas LA. Vitamin D3 Is More Potent Than Vitamin D2 in Humans. J Clin Endocrinol Metab. 2010 Dec 22.

5 thoughts on “Is Vitamin D Deficiency Making Kids Fat?

  • February 23, 2011 at 1:23 pm

    Great post! And yes, Vitamin D3 Deficiency does increase the likelihood of childhood obesity in children deficient in the nutrient, as well as in the children of mothers who were deficient during pregnancy.

    Amazingly, Vitamin D Deficiency has been associated with increased risk factors for more than 20 different diseases and illnesses.

  • January 21, 2011 at 12:28 am

    I think the main reason kids can become fat is lack of exercise and eating unhealthy junk food..

  • January 12, 2011 at 4:56 pm

    If vitamin D deficiency is one of the treatable causes of obesity, then a studies has shown that the more vitamin D in your diet, the less you weigh.

    • January 13, 2011 at 10:19 am

      Hey Susan, I think there’s a number of factors involved with some playing a bigger role than others. Eating ‘crap all day and playing video games’ would certainly be one of the biggest factors.


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