Unless you’re lucky enough to enjoy a sunny climate year-round, fall signals the season that you may want to start taking a vitamin D supplement—but not just any form of vitamin D. A recent study finds that vitamin D3 (cholecalciferol) does a better job of maintaining vitamin D levels than the D2 (ergocalciferol) form.
Normally, our bodies can make some vitamin D from the sun provided we get regular exposure to sunlight on uncovered skin—this means no sunscreen too. But if you spend most of your time indoors, or live in a northern climate with little UV exposure in the fall and winter months, vitamin D stores can drop below healthy levels. In fact, it is estimated that as many as 60% of us are deficient in vitamin D.
That’s why this new study comparing vitamin D3 to D2 is such good timing.
The researchers from the University of Otago in New Zealand, found that 1,000 IU of vitamin D3 maintained vitamin D stores during winter months, whereas levels decreased with the same dose of vitamin D2.
For the study they recruited 95 people between the ages of 18 and 50 and divided them into 3 groups. The first group received a placebo, and the second and third groups received 1,000 IU daily doses of vitamin D2 or D3 for 25 weeks starting at the end of summer.
Overall, total serum concentrations were 21 nmol/l lower in participants receiving vitamin D2 compared with those receiving D3, among whom total serum concentrations remained the same.
These findings contribute to mounting evidence that vitamin D3 and vitamin D2 have different effects on your body. As a result, it is important which form of vitamin D you choose to help maintain your health.