How does UVB radiation activate vitamin D?

Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
UVB activates vitamin D through cholesterol. That's why your blood cholesterol levels rise in the winter. Because of the lack of sunlight, you don't have enough active vitamin D in winter, so your body pumps up your cholesterol in the hope of converting as much as possible to active vitamin D.

This serves as another example of an evolutionary trade-off between procreation and longevity. To protect us from deficiencies of vitamin D, we've evolved to have higher levels of cholesterol. So now we survive to mate and to be able to stand up strong and look good—only to be felled by high LDL cholesterol and consequent heart disease and stroke.
You: Staying Young: The Owner's Manual for Extending Your Warranty

More About this Book

You: Staying Young: The Owner's Manual for Extending Your Warranty

International bestselling authors of YOU: The Owner's Manual and YOU: On a Diet give you all the tools and know-how to stay young and defy the ageing process. Drawing lively parallels between your...

Continue Learning about Sun Care

Do I have tanorexia?
Susan EvansSusan Evans
Anytime someone is dealing with a compulsive disorder they should seek help from a professional. Peo...
More Answers
What is UPF for sun-protective clothing?
Phillip J. Landrigan, MDPhillip J. Landrigan, MD
Items of clothing are rated according to their UPF -- ultraviolet protection factor. The UPF rat...
More Answers
What ingredients in sunscreens are best in protecting me from the sun?
Dr. Mehmet Oz, MDDr. Mehmet Oz, MD
The most effective protection from a sunscreen comes from one that contains a high sun protection ...
More Answers
What are the benefits of sun exposure?
UCLA HealthUCLA Health
The sun’s UV rays help the body to produce vitamin D, which is essential for health. The key is mode...
More Answers

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.