Types of Vitamin D: Vitamin D2 Vs. D3

You probably realize the importance of getting enough of the all-important D vitamin, but did you know there are two types of vitamin D? If your doctor tells you your vitamin D levels are low, do you know how to select the best vitamin supplement to get maximal health benefits? Find out more about the two types of vitamin D - and which is the better choice.

Vitamin D Types: Vitamin D2 vs. Vitamin D3

Vitamin D2, also known as ergocalciferol, is a type of vitamin D made by lower species such as fungi in response to ultraviolet light. Vertebrates don't make it. The second type of vitamin D is vitamin D3 or cholecalciferol. It's the type made by humans and other animals when they're exposed to sunlight. Both forms can be converted into the active form of vitamin D called calcitriol, but some experts believe vitamin D2 is not as efficiently converted to calcitriol as vitamin D3 is.

In a recent study published in the Journal of Clinical Endocrinology and Metabolism, researchers put the two types of vitamin D to the test. They gave 64 seniors with low vitamin D levels either vitamin D2 or vitamin D3 as a supplement for twelve months. During this time they measured their blood levels of vitamin D.

This study showed how difficult it is to raise vitamin D levels even with supplements. After giving these seniors 1600 I.U. of vitamin D a day, 20% still had low vitamin D levels by the completion of the study. Secondly, it showed that vitamin D3 was more effective at raising vitamin D levels than the D2 form, although the difference wasn't large.

Vitamin D2 vs. D3: The Bottom Line?

If your doctor says you need to supplement with vitamin, ask your pharmacist specifically for vitamin D3 or cholecalciferol. Some pharmacists still think the two types of vitamin D are equivalent, but you'll know better. Make sure you're getting the type of vitamin D your body can best use.

References:

Medscape.com. "Serum Vitamin D Levels Higher with Intake of Vitamin D3 Than Vitamin D2"