As I said in a past newsletter, Michael Holick, M.D., PhD has written the first book about vitamin D that is written for the general public, The UV Advantage. This book is an incredibly important read for anyone interested in preventing numerous health problems and bettering their health, but is even more essential for those who follow the "experts" recommendations to stay out of the sun.

Dr. Holick, one of the world's foremost authorities on vitamin D and a full professor of medicine, dermatology, biophysics and physiology at the Boston University School of Medicine, expands on the great importance of sun and vitamin D to your health, including what to do if regular sun exposure isn’t a realistic option for you.

1. Why did you write "The UV Advantage"?

I wrote the UV Advantage to disseminate the message that some exposure to sunlight is very beneficial to overall health and well-being.

2. Who would benefit from reading this book?

I believe that everyone who reads this book will benefit from its message. This is especially true for young and middle-aged adults who were brought up in a culture that recommended avoidance all sun exposure. This puts this group at high risk of vitamin D deficiency and many other chronic diseases associated with the deficiency.

In addition parents will be especially interested because it is now recognized that adequate vitamin D nutrition and sensible sun exposure during childhood not only will maximize the bone health of their children but may decrease their risk of many chronic diseases in life later including type 1 diabetes, multiple sclerosis, rheumatoid arthritis and common cancers.

3. What do you recommend to people who work indoors, have difficulty getting outdoors, or for whatever reason are unable to get sun exposure regularly? Is there a substitute to the sun?

It is reasonable for people who, for whatever reason, cannot take advantage of reasonable sun exposure to satisfy their body’s vitamin D requirement by taking a vitamin D supplement. Most experts, including myself, believe that at least 1,000 IU of vitamin D a day is necessary to maintain healthy blood levels of vitamin D in the absence of any sun exposure.

4. You mention that bright light therapy is effective for treating depression and SAD. Is this for the vitamin D, or is another component/result of the UVB rays responsible for the benefit? I ask because studies have found that low vitamin D may contribute to chronic fatigue and depression (1,2) and another study found that vitamin D was more effective in treating depression than using light boxes. Do you agree with these findings?

Bright light therapy is effective in treating seasonal affective disorder because of its effect on suppressing melatonin production in the pineal gland. However, often people during the winter suffer from malaise, muscle weakness, muscle aches and bone pain that often can exacerbate their depression. A study has been conducted demonstrating that vitamin D supplementation during the winter does help reverse some of the symptoms associated with SAD.

5. Is there any way to reduce sun damage, from previous sunburns for example, that’s already been done?

There are ways of reducing photodamage from previous burns. I have included some of those approaches in my book.

6. You mention in "The UV Advantage" that you are not an advocate of tanning per se, however, for people who do not have access to regular sunlight, say during the winter months, would using a tanning bed for the sole purpose of gaining vitamin D be beneficial, or would vitamin D supplements or cod liver oil be a better choice?

For people who wish to tan, I recommend that they tan responsibly. They will benefit from the tanning process because it will enhance their skin’s production of vitamin D. We recently conducted a study on tanners and nontanners and found that tanners had much higher and healthier blood levels of vitamin D compared to nontanners at the end of the winter and that their bone health was better.

For those who do not wish to tan and are concerned about vitamin D deficiency, taking a vitamin D supplement and/or cod liver oil that equals 1,000 IU of vitamin D a day should satisfy the body’s vitamin D requirement. Whether there are other benefits from exposure to tanning bed radiation on ß endorphin levels and other physiologic functions is not as well understood and obviously cannot be replicated by simply taking vitamin D.

7. If you could give readers one bit of advice from "The UV Advantage," what would it be?

The one bit of advice from "The UV Advantage" is that you should not be sun-phobic because it increases your risk of many serious chronic diseases. Consider the sun as a friend and use it sensibly i.e., take advantage of its beneficial effects while avoiding the damaging effects due to chronic excessive exposure.

8. What is your opinion of sunscreens and sunblocks? Should they be used, and if so, what type is best? Do you believe the chemicals in sunscreens can be harmful?

Sunscreens and sunblocks are important for preventing sun damage due to excessive exposure to sunlight. More importantly they prevent sun burning, which is considered to be a major cause of the most devastating form of skin cancer, melanoma. However, a sunscreen with an SPF of 8 when applied properly will reduce the skin’s ability to make vitamin D by more than 95 percent.

Therefore, I recommend that people who are outdoors for only a few minutes need not wear a sunscreen. However, if they are going to be out for more than a few minutes they should take advantage of the beneficial effect of sunlight and then after those few minutes, as outlined in the tables in my book, they should topically apply a sunscreen with an SPF of least 15. I always recommend broad-spectrum sunscreen, which absorbs both the UVA and UVB.

There are always concerns about chemicals in any topical preparation that could potentially be absorbed through the skin into the blood stream and cause harm to the body. However, to date there is no evidence that the chemicals in sunscreens have any harmful effect.

Dr. Mercola's Comment: Although Dr. Hollick does not believe that sunscreens have any harmful effects, I don't believe in using them at all and advise avoiding them. One can avoid the damage from the sun by staying out of the sun during the harmful times from 10 a.m. to 2 p.m., staying in the shade during this time or wearing long sleeve shirts, long pants and a hat.

9. Do you have plans to write another book?

I do plan to write at least three additional books on skin health, hair health and bone health.

Sun Protects Against Cancer

RDAs of Vitamin D Far Too Low

Learn Why the Myth of the Sun Causing Skin Cancer Can Hurt Your Health

Let the Sun Shine In (Especially When Pregnant)

Why You Need to Have Your Vitamin D Level Tested Now

Test Values and Treatment for Vitamin D Deficiency

References

1. Puchacz E, Stumpf WE, Stachowiak EK, Stachowiak MK. Vitamin D increases expression of the tyrosine hydroxylase gene in adrenal medullary cells. Brain Res.Mol.Brain Res. 1996;36:193-6.

2. Gloth FM 3rd, Alam W, Hollis B. Vitamin D vs broad spectrum phototherapy in the treatment of seasonal affective disorder. J Nutr Health Aging. 1999;3(1):5-7.