Just Ask Terry

Terry is happy to provide his opinion on diet and nutrition, supplements and lifestyle choices. This information is for educational purposes only. It is not meant to replace the advice of your physician and is not to be considered medical advice, diagnosis or treatment. Should you have any concerns please contact your physician directly.

Q. Hi Terry, “Now that the days are getting shorter and I am not spending a lot of time outdoors, I was thinking of adding a vitamin D supplement to my regimen. However, I see that there are two forms at the store: vitamin D2 and vitamin D3. Are they both good, or is one better than the other? Thanks!” — Katie V., Milwaukee, WI

A. Dear Katie, You are on the right track when it comes to adding a vitamin D supplement, especially for those of us living in Northern climates. The amount of sunlight is decreasing and changes in the weather mean we are spending less time outside. While your body is capable of making vitamin D (triggered by sunlight striking your skin), you need about 15 to 30 minutes of sunlight a day with most of your skin exposed (no sunscreen) to get this process in motion in order to create good amounts of vitamin D.

You are probably already aware of the role vitamin D plays in promoting calcium absorption and preventing osteoporosis. But every day, new research is finding that vitamin D plays a crucial role in multiple health issues, whether it is helping to reduce the risk of heart disease and dementia, preventing diabetes, slowing the progress rate of cancer, and even promoting weight loss! I wish more people would follow your lead, because we could probably dramatically reduce the amount of illness in this country if everyone had optimal levels of this crucial vitamin.

Vitamin D2 (ergocalciferol) is the form of vitamin D synthesized by plants. Cholecalciferol, or vitamin D3, is the form that is produced by the human body. While both forms can increase circulating vitamin D levels, I believe vitamin D3 is far superior. Vitamin D2 is poorly utilized compared to vitamin D3. In fact, in a study of the two forms, researchers found that vitamin D2 is only one-third the potency of vitamin D3. (J Clin Endocrinol Metab. 2004;89:5387-91.) That means you’d have to take 3 times as much D2 to get the same effects as vitamin D3. I usually recommend about 2,000-3,000 IU a day for most people.

Healthy Regards!

Terry . . . Naturally