by Craig Weatherby
The title of the TV show “Northern Exposure” fits a recent, tan-related, controversy to a “T”.
Recently, Alaska Governor Sarah Palin took some ribbing for her installation of a tanning bed in the official residence.
Comics implied that she was driven by cosmetic considerations, and many people snickered at the seeming extravagance.
But folks like us, who live in the Pacific Northwest, know that our region's lack of light—and Alaska's far darker scenario— is no laughing matter.
In fact, lack of UV sunlight produces two serious health problems:
- Depression, in the form of seasonal affective disorder or SAD.
- Increased cancer risk, because the body makes anti-cancer vitamin D from UV sunrays.
Last month, dermatologists at the fourth international congress of the Society for Melanoma Research published review articles that overstated the evidence of cancer risks from tanning beds, and grossly understated the powerful anti-cancer effects of the vitamin D they create in users' bodies.
Sadly, the media failed to challenge their assumptions and unfounded fears.
It seems likely that you can raise skin cancer risk by overdoing sun exposure or tanning beds.
But the risk of light-to-moderate tanning bed use appears very small, and it needs to be considered in the context of the likelihood of reductions in far more common killer cancers.
And recent research from Italy indicates that vitamin D generated by UV rays actually protects against melanoma.
Italians link melanoma risk to lack of vitamin D… not UV rays
Scientists at Italy's University of Padova uncovered a likely link between higher melanoma risk and a genetic variation that impairs the ability of vitamin D to attach to cell receptors (Mocellin S, Nitti D 2008).
Scientists examined the existing scientific literature on the association between melanoma and common variants of a vitamin D receptor gene called Bsml.
Variations in the Bsml gene mean that people exposed to the same amount of UV rays will have different levels of vitamin D in their bodies.
|Fish fit the vitamin D bill; Sockeye salmon stand out|
Certain fish rank among the very few substantial food sources of vitamin D, far outranking milk and other D-fortified foods.
Among fish, wild Sockeye Salmon may be the richest source of all, with a single 3.5 ounce serving surpassing the US RDA of 400 IU by about 70 percent:
In turn, this means that some people have more vitamin D-related protection against cancer than others.
The Italian team concluded that people with certain variants of the vitamin D receptor gene may be at increased risk for melanoma.
As they wrote, “These findings prompt further investigation on this subject and indirectly support the hypothesis that sun exposure might have an anti-melanoma effect through activation of the vitamin D system” (Mocellin S, Nitti D 2008).
Previous research has shown that vitamin D has significant protective effects against the development of cancer, because it regulates cells growth, cell differentiation and cell death.
There's also overwhelming epidemiological evidence that sun exposure, which triggers the body to produce vitamin D, exerts strong anti-cancer effects.
And there is equally strong epidemiological evidence that people with lower vitamin D levels in their bodies—from a lack of UV exposure and any compensating dietary intake—suffer higher rates of major cancers.
Evidence suggests low tanning-bed risk
It is true that UV rays harm the skin by damaging DNA and cell structures… effects that tend to promote cancer.
Last month, researchers at Boston University Medical Center published their review of medical studies that examined the risk of melanoma – the rarest but most serious type of skin cancer – from use of sunlamps and tanning beds.
As they wrote, “Results suggest a modest association between sunlamp use and melanoma risk, and increasing risk with greater frequency and duration of use. No association with tanning bed use was found, but sufficient lag time may not have elapsed to assess a potential effect” (Clough-Gorr KM et al. 2008).
One large study, conducted in Scandinavia, produced evidence of an increased melanoma risk among tanning bed users, but it did not look at the rates of other cancers (Autier P 2004).
But last month, other researchers published far less measured papers.
Alarmist anti-UV assertions flout the facts
The authors of papers published in the October, 2008 issue of the journal Pigment Cell & Melanoma Research suggested that the UV rays in tanning beds increase the risk of melanoma.
These papers come on the heels of a nationwide campaign by the Indoor Tanning Association that questioned the weak evidentiary link between UV exposure and melanoma.
We cannot say whether tanning beds are riskier than sun exposure, but as their ads noted, UV exposure from any source enables the body to produce anti-cancer vitamin D.
The assertions made in the journal articles were based on very weak evidence, failed to make any distinction between moderate and heavy use of tanning beds, and failed to consider any tanning-related reductions in the risk of far more common cancers.
One of the papers was a review article by epidemiologist Marianne Berwick of the University of New Mexico, who suggested that tanning beds may be associated with risk of melanoma.
Yet her own words contradict that notion (key points underlined for emphasis):
“Epidemiologic data—incomplete and unsatisfactory—suggests that tanning beds are not safer than solar ultraviolet radiation...” (Berwick M 2008).
In other words, there is weak evidence that regular use of tanning beds may not be safer than going about in the sun regularly.
This penetrating glimpse into the obvious ignores the preponderance of evidence, which shows that cancer rates fall when sun exposure is greater, thanks to sun-induced vitamin D.
Hard to get enough D from the diet
Dr. David E. Fisher, president of the Society of Melanoma Research claims—despite far greater evidence to the contrary—that the potential risks of tanning beds outweigh any possible benefit.
He must have been living under a rock for the past five years, while research affirming the anti-cancer effects of vitamin D grew from a stream to a flood.
In fact, the available evidence shows that sun exposure is not a strong risk factor for melanoma, with the recent Italian findings adding weight to the idea that moderate UV exposure helps prevent melanoma.
And while Dr. Fisher's team grudgingly admitted the anti-cancer potential of vitamin D, they asserted a misleading point: “… oral supplementation is fully capable of maintaining systemic levels” (Tran TN, Schulman J, Fisher DE 2008).
In fact, very few people consume enough vitamin D to maintain likely cancer-curbing levels.
Only fatty fish contain significant amounts of vitamin D—wild salmon and albacore tuna are the best sources by far (se our sidebar)—while most multi-vitamins contain much less.
In fact, it is hard to raise vitamin D levels to adequate levels by diet alone.
(For example, a Vital Choice team member diagnosed with vitamin D deficiency has been taking very-high-dose vitamin D prescribed by a physician, but is still very deficient several weeks later.)
And the US RDA for vitamin D—which is the amount in most multi-vitamins—is grossly inadequate to produce sufficient levels in the body, which is why researchers have been pleading for it to be raised from 200 IU (for adults up to age 50) to 1,000 or 2,000 IU.
- Abbas S, Nieters A, Linseisen J, Slanger T, Kropp S, Mutschelknauss EJ, Flesch-Janys D, Chang-Claude J. Vitamin D receptor gene polymorphisms and haplotypes and postmenopausal breast cancer risk. Breast Cancer Res. 2008;10(2):R31. Epub 2008 Apr 17.
- Autier P. Perspectives in melanoma prevention: the case of sunbeds. Eur J Cancer. 2004 Nov;40(16):2367-76.
- Berwick M. Are tanning beds "safe"? Human studies of melanoma.Pigment Cell Melanoma Res. 2008 Oct;21(5):517-9.
- Clough-Gorr KM, Titus-Ernstoff L, Perry AE, Spencer SK, Ernstoff MS. Exposure to sunlamps, tanning beds, and melanoma risk. Cancer Causes Control. 2008 Sep;19(7):659-69. Epub 2008 Feb 14.
- de Winter S, Pavel S. [Tanning beds: effect on skin cancer risk unclear] Ned Tijdschr Geneeskd. 2000 Mar 4;144(10):467-70. Review. Dutch.
- Mocellin S, Nitti D. Vitamin D receptor polymorphisms and the risk of cutaneous melanoma: a systematic review and meta-analysis. Cancer. 2008 Sep 24. [Epub ahead of print]
- Su J, Pearce DJ, Feldman SR. The role of commercial tanning beds and ultraviolet A light in the treatment of psoriasis. J Dermatolog Treat. 2005;16(5-6):324-6. Review.
- Swerdlow AJ, Weinstock MA .Do tanning lamps cause melanoma? An epidemiologic assessment.J Am Acad Dermatol. 1998 Jan;38(1):89-98.
- Ting W, Schultz K, Cac NN, Peterson M, Walling HW. Tanning bed exposure increases the risk of malignant melanoma. Int J Dermatol. 2007 Dec;46(12):1253-7.
- Tran TN, Schulman J, Fisher DE. UV and pigmentation: molecular mechanisms and social controversies. Pigment Cell Melanoma Res. 2008 Oct;21(5):509-16.