American Journal of Medicine, internal medicine, medicine, health, healthy lifestyles, cancer, heart disease, drugs

Sunshine: Clinical Friend or Foe?

But soft! What light through yonder window breaks? It is the east, and Juliet is the sun! Arise, fair sun, and kill the envious moon …

Shakespeare, W: Romeo and Juliet, Act II, Scene II.

When you live in Arizona, the sun is always with you. Living here makes it easy to understand that the sun has been a central factor in human existence, iconography, and a variety of religions in ancient Egypt, Indo-Europe, and Meso-America since the beginning of recorded or archaeologically defined history. (1,2)

The first scientific writings concerning the benefit of sun therapy emanated from the investigations of Niels Ryberg Finsen, who won the Nobel Prize for his work with heliotherapy (Helios in ancient Greek = sun).(3) Finsen observed the effect of sunlight on his own fragile health. He supplemented these personal observations with experiments on animals and eventually began a series of clinical trials using natural and artificial sunlight therapy for 2 skin conditions: smallpox and tuberculosis of the skin. The dermatologic lesions of both conditions responded to natural and artificial sunlight exposure in these experiments, eventually leading to the Nobel Prize in 1903.(4)

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– Joseph S. Alpert, MD, Editor-in-Chief

This article originally appeared in the April 2010 issue of The American Journal of Medicine.

2 Responses to “Sunshine: Clinical Friend or Foe?”

  1. Contrary to your comment in a recent editorial (1), there is overwhelming scientific evidence suggesting that increased exposure to sunlight, which increases vitamin D3 synthesis, and a person’s vitamin-D status, can modify the risks and outcomes of many deadly cancers.

    Multiple tumor cell lines including colon, lung, breast, and prostate have shown response to the anti-proliferative and pro- differentiating activity of 1,25- dihydroxy VitaminD3 [1,25(OH)2D3] (2). Most cells in our body, including activated macrophages, kidney, colon, prostate, breast, and brain, among others, have the ability to express 25-hydroxyvitamin D-1-hydroxylase (1-OHase) and make 1,25(OH)2D3. While increasing sun exposure or vitamin D intake will not increase the renal production of 1,25(OH)2D, it is believed that raising blood levels of 25-hydroxy vitamin-D [25(OH)D] to 30 ng/ml provides adequate substrate for the non-renal conversion to 1,25(OH)2D in these organs (2). When patients with metastatic prostate cancer (MPC) were treated with docetaxel and 45 micrograms of DN-101 (a high-dose oral formulation of calcitriol), an improvement in overall survival was noted without any unexpected toxicities (3). Recently, a novel group of compounds called Gemini analogs have been highly effective in inhibiting colon tumor growth in mice without any major toxicity.

    Maintenance of an adequate vitamin-D status is also important for cancer prevention. Woo et al. (4) reported that MPC patients who received 2000 IU/d Vitamin-D had ~ 50% reduction in PSA levels after 21 months. In an animal model (5), Vitamin D-sufficient mice injected with colon cancer cells (MC-26) had a 40% decrease in tumor growth when compared with mice that were Vitamin D-deficient. Women ingesting 1400-1500 mg/d calcium and 1100 IU/d vitamin D3 for 4 years reduce their risk for developing cancer by 60% (6). Supporting this data, women in the Women’s Health Initiative study who were vitamin D-deficient had a 253% increased risk for developing colorectal cancer during the eighth year of the study compared with women who were vitamin D sufficient at the beginning (7).

    The New Zealand Bone and Mineral Society, Australian College of Dermatologists and Cancer Council for Australia have recommended a balance between avoiding the increased risk for skin cancer and achieving enough ultraviolet radiation to maintain adequate vitamin-D levels. I would conclude by reminding that limited sensible exposure to sunlight or ultraviolet B radiation is more effective in raising blood levels of 25(OH)D than 1000 IU vitamin-D3 taken daily for adults of most skin types (2).

    Nishant Tageja MD
    Department of Internal Medicine
    Wayne State University/ Detroit Medical Center
    Detroit, MI

    References –
    1) Alpert JS. Sunshine: clinical friend or foe? Am J Med. 2010 Apr;123(4):291-2

    2) Holick MF. The vitamin D deficiency pandemic and consequences for nonskeletal health. Mol Aspects Med. 2008 Dec;29(6):361-8.

    3) Beer TM, Ryan CW, Venner PM et al. Double-blinded randomized study of high-dose calcitriol plus docetaxel compared with placebo plus docetaxel in androgen-independent prostate cancer: A report from the ASCENT investigators. J Clin Oncol 25: 669–674, 2007

    4) Woo TC, Choo R, Jamieson M et al. Pilot study: Potential role of vitamin D in patients with PSA relapse after definitive therapy. Nutr Cancer 51: 32–36, 2005

    5) Tangpricha V, Spina C, Yao M et al. Vitamin D deficiency enhances the growth of MC-26 colon cancer xenografts in Balb/c mice. J Nutr 135: 2350–2354, 2005

    6) Lappe JM, Travers-Gustafson D, Davies KM et al. Vitamin D and calcium supplementation reduces cancer risk: Results of a randomized trial. Am J Clin Nutr 85: 1586–1591, 2007

    7) Holick MF: Calcium plus vitamin D and the risk of colorectal cancer. N Engl J Med 354: 2287. 2006

  2. Dear Dr. Tageja: Thanks for your knowledgeable comment. I am aware that many authorities are convinced that vitamin D therapy, either through sunlight or by oral supplementation, is a factor in the prevention of cardiovascular and oncologic disease. However, there are as yet no real hard end-point, evidence-based, studies with carefully chosen outcomes that support definitively what you so eloquently argue. Given the potential oncologic risks of excessive sunlight exposure, I think we need to be judicious in our recommendations concerning what constitutes “appropriate” sunlight exposure. Hopefully, large, randomized trials will soon be underway to help us decide whether sunlight therapy is or is not beneficial to patients with CV and oncologic disease. Sincerely, Joseph Alpert