Which Form of Vitamin D Is Best?

Vitamin D3 is more potent than D2, according to a meta-analysis.

By now you may have learned what vitamin D can do for your bones, muscle, your heart, and even your telomeres (those protective caps on chromosomes), but are you getting the right amount in the right form to boost levels optimally?

Vitamin D is perhaps the most unique and certainly the most broadly influential “vitamin” in our diet. Given the scope of its action it may be no surprise this vitamin is not a vitamin at all, but works more like a hormone. Supplement users are acquainted with vitamin D in two forms: vitamin D2, available in plants and fortified foods, and vitamin D3, the natural form produced in the partnership between skin and sunshine and also found in some animal foods like egg yolks and oily fish.

Which one are you getting? Does it matter? Because of mixed data on potency, the scientific community has long been at odds regarding which form is best to bring levels in the blood stream up to optimal status; and finally an answer has been unveiled. For the first time, a systematic review and meta-analysis including 17 studies comparing the use of vitamin D2 to D3 suggest that D3 is the one most effective at raising blood levels of the vital-for-health vitamin.

Published in the American Journal of Clinical Nutrition, most of the evidence deems D3 as superior to D2. “Our results suggest a favoring toward cholecalciferol [D3] rather than ergocalciferol [D2] supplementation with respect to the more effective improvement of vitamin D status,” wrote the researchers.

Why is there a discrepancy between the forms? They both, after all, contribute to active circulating levels of vitamin D. Researchers believe the answer to this question is becoming clearer. Both types must undergo a series of conversions in the body to become “active.”  Becoming calcitriol, the active form, involves the liver and the kidney, some chemical reactions, and a bit of structural manipulation before it can exert a benefit on nearly every cell in the body. Put simply, vitamin D2 is not as easily converted to calcitriol as vitamin D3. Higher rates of conversion not only mean it is more effective, it also has implications for how long this hormone will be around to confer benefits. Given the information currently available, vitamin D3 seems to be the best bang for your buck when it comes to supplementation.

With the majority of people vitamin D deficient, the need for supplementation is vast. Though our bodies do make vitamin D from sun exposure, the amount of sunshine in northern countries is not sufficient, especially during the winter months, for the body to produce enough vitamin D. This makes it absolutely necessary to get adequate vitamin D from foods naturally rich in vitamin D, fortified foods, and dietary supplements.

Even in the summer months, as people actively try to avoid excessive UV exposure and take protective measures, which should absolutely be taken to avoid sunburn and higher risk of skin cancer, vitamin D status may still be in peril. This research emphasizes that there’s no need to change your defense against too much sun, even for the sake of vitamin D. High-quality dietary supplement such as Ageless Actives are available and offer more than two times the recommended daily value of vitamin D3.

Stay on top of your sun protection and take comfort in knowing that you don’t have to compromise your skin for your nutrition—when it comes to this hormone, the best defense against deficiency or low status may be offensive supplementation with D3.

Reference:  Tripkovic L, Lambert H, Hart K et al. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. Am J Clin Nutr 2012. doi: 10.3945/​ajcn.111.031070