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Sunscreen, Cancer and Vitamin D – What Are the Facts?

Sunscreen, Cancer and Vitamin D – What Are the Facts?

2015 - 06 - 30 | Author: Elyse Schear

sunbather Summer has arrived, and with it come sunny afternoons on the beach or at the pool. As we reach for that tube of suntan lotion, we may find ourselves hesitating because of all the conflicting information that’s been in the news about sun exposure risks, the efficacy and safety of suntan lotion, and how this relates to our overall health.

Some claim that we should avoid shielding ourselves from the sun, because the lack of sun exposure may lead to health problems, including cancer. Others maintain that we should protect ourselves from the sun’s rays at all times and at all costs, because the sun’s rays are carcinogenic. For example, the American Cancer Society tells us that many skin cancers are caused by exposure to ultraviolet (UV) rays from the sun or other sources.

But how do we, as consumers, interpret all this vast and confusing evidence?

This article aims to raise awareness about what we do know about sun exposure, what we don’t know, and to provide some tips for finding a balance between having concerns and enjoying life to the fullest.

Let’s begin by taking a look at what the research shows. First, we’ll review those facts that are well-established and generally known and accepted. Next, we will look at more recent, lesser-known discoveries. Finally, we’ll boil it all down to a short list of suggestions you can follow for getting the most out of your time in the sun, with the least risk to your health.

Generally known and accepted facts about sun exposure:

  • Some sunlight is necessary for good health. Human beings need exposure to some ultraviolet radiation (UV) from the sun to help our bodies create vitamin D. In theory, as long as we have access to adequate sunlight on a regular basis, our bodies should produce the vitamin D that we need.
  • Vitamin D isn’t technically a vitamin, but a fat-soluble steroid hormone that exists naturally in our skin. When exposed to the ultraviolet radiation (UV) in sunlight, the skin converts the hormone into D3, a form of vitamin D that our bodies require for healthy functioning.
  • Low vitamin D levels are on the rise. Recent findings link living in cloudy climates and spending minimal time outdoors as risk factors for low vitamin D. In one study, researchers at the University of California, San Diego School of Medicine's Department of Family Medicine and Public Health recently found that people who live in regions with low sunlight may have a higher risk of pancreatic cancer, possibly because they don't get enough vitamin D from the sun. The researchers reached their conclusions after reviewing information from more than 100 countries. They had previously linked higher vitamin D levels to lower levels of breast and colorectal cancer.
  • Too much sunlight can cause skin cancer, and skin cancer is on the rise. Skin canceris the most common of all cancers. About 3.5 million cases of basal and squamous cell skin cancer are diagnosed in the United States each year. Melanoma, a more dangerous type of skin cancer, is projected to account for more than 73,000 cases of skin cancer in 2015. Known risk factors for skin cancer from sun exposure include fair skin, a history of tanning and sunburn, family history of skin cancer, and a large number of moles.
  • The exact amount of sun exposure that is safe is unknown, but it is generally accepted that exposure should be gradual, and stop short of sunburn.
  • There are two types of UV from sunlight, UVB and UVA. UVB rays can cause sunburn but also help the skin produce vitamin D. UVA rays penetrate deep into the body, accelerate skin aging, may suppress the immune system and may cause skin cancer.
  • Some *sunscreen products contain ingredients that may be harmful. While modern cosmetic products, including *sunscreen, are made with ingredients that are designed not to penetrate the skin, this practice is not universal, and some chemicals are entering our body through our skin. The research is ongoing, but so far, the consensus is that some of these chemicals have the potential to cause health issues, including cancer.

More recent, lesser known facts about sun exposure:

(Note: Some of this is probably not new to followers of BeatCancer.Org!)

  • Eating whole foods, particularly fruits and vegetables, helps reduce many forms of cancer, including skin cancers. A diet rich in plant foods supplies the body with antioxidants and phytochemicals, which have been shown, over and over to reduce the risk of cancer.
  • Herbs and spices, such as oregano, cinnamon, cloves, ginger, turmeric and garlic, as well as substances found naturally in certain fruits and vegetables, such as lipoic acid, have been shown to reduce the skin-aging effects of sun exposure.
  • Higher coffee intake—four or more cups per day—has been associated with a modest decrease in the risk of melanoma.
  • A high-fat diet is linked to an increased risk of skin cancers.
  • A low-dose aspirin regimen may be helpful in preventing skin cancers. In 13 studies, it was shown that daily intake of 150 mg or less of aspirin reduced the risk of developing multiple types of skin cancer (the presumed mechanism here being anti-inflammatory).
  • The amount of sun exposure we need for our skin to synthesize vitamin D may be surprisingly little. According to a study at Memorial Sloan Kettering Cancer Center, “Peak ultraviolet B irradiation for vitamin D synthesis occurs around 12 pm Eastern Standard Time (EST). In Boston, MA, from April to October at 12 pm EST an individual with type III skin with 25.5% of the body surface area exposed, would need to spend 3 to 8 minutes in the sun to synthesize 400 IU of vitamin D [although] it is difficult to synthesize vitamin D during the winter months in Boston. For all study months in Miami, FL, an individual with type III skin would need to spend 3 to 6 minutes at 12 pm EST to synthesize 400 IU. The duration to attain 1000 IU of vitamin D is longer in all scenarios.”Type III skin represents a standard measurement on the Fitzpatrick Skin Phototype scale, a tool used by dermatologists to help determine patients’ risk factors for sunburn and skin cancer. Fitzpatrick skin phototypes are numbered from I “burns easily, never tans” to VI “never burns, tans profusely”. The lower the Fitzpatrick number, the higher the risk for skin cancer. (http://goo.gl/q5nxKF) Vitamin D synthesis occurs faster in individuals with lighter Fitzpatrick skin types.
  • Very low blood levels of vitamin D might require supplementation.
  • According to the Environmental Working Group (EWG), sunscreens with the ingredient retinyl palmitate may trigger damage, possibly cancer. Those with oxybenzone can disrupt the hormone system.
  • The EWG also says that the SPF (Sun Protection Factor) levels on *sunscreen labels are misleading. SPF refers only to the sun’s UVB rays—those that burn the skin—but not to the UVA rays, which penetrate the body and can potentially cause cancer. Anything higher than SPF 50 is ineffective, and may encourage people to stay in the sun longer.

What you can do:

  • Eat a mostly plant-centered low-fat diet. Enjoy a variety of herbs and spices.
  • When you are in the sun for prolonged periods, apply a *sunscreen between 30 and 50 SPF that does not contain oxybenzone or retinyl palmitate. Follow the package directions for re-application. For a detailed analysis of sunscreens, see the Environmental Working Group’s Guide to Sunscreens (http://www.ewg.org/2015sunscreen/).
  • Have your vitamin D levels tested to see if you require supplements to help boost your vitamin D levels. For many people, taking supplements combined with safe sun exposure will help normalize your vitamin D levels.
  • If you are fair skinned, live in the northern hemisphere and/or haven’t spent much time in the sun, start with short periods of sun exposure. See Dr. Joseph Mercola’s article Little Sunshine Mistakes that Can Give You Cancer Instead of Vitamin D (http://goo.gl/PBWwVt) for specific suggestions on exposure times.
  • If you are a coffee drinker, drink the right kind of coffee!
  • Talk to your health care provider about whether a low dose of aspirin is safe or recommended for you.
  • If you are taking any medications, ask your pharmacist or doctor if you need to avoid the sun while taking them.
  • Don’t ignore changes in your skin; it’s always best to see a dermatologist to rule out skin cancer.

*Sunumbra is a "Trusted Vendor" of BeatCancer.Org

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References:

[1] Terushkin V, Bender A, Psaty EL, et al. Estimated equivalency of vitamin D production from natural sun exposure versus oral vitamin D supplementation across seasons at two US latitudes. J Am Acad Dermatol. 2010 Jun; 62(6): 929.e1-9.

[2] Wolpowitz D, Gilchrest BA. The vitamin D questions: how much do you need and how should you get it? J Am Acad Dermatol. 2006 Feb; 54(2): 301-17.

[3] Norman AW. The history of the discovery of vitamin D and its daughter steroid hormone. Ann Nutr Metab. 2012; 61(3): 199-206.

[4] Klingberg E, Oleröd G, Konar J, et al. Seasonal variations in serum 25-hydroxy vitamin D levels in a Swedish cohort. Adv Exp Med Biol. 2014; 810: 303-28.

[5] Bikle DD.The vitamin D receptor: a tumor suppressor in skin. Adv Exp Med Biol. 2014; 810: 302.

[6] Holick MF. Sunlight, ultraviolet radiation, vitamin D and skin cancer: how much sunlight do we need? Adv Exp Med Biol. 2014; 810:1 -16.

[7] Pojsupap S, Iliriani K, Sampaio TZ, et al. Efficacy of high-dose vitamin D in pediatric asthma: a systematic review and meta-analysis. J Asthma 2014 Nov 21: 1-9.

[8] Wannit Tongkao-on W, Clare Gordon-Thomson C, Dixon K. Novel vitamin D compounds and skin cancer prevention. Dermatoendocrinol. 2013 Jan 1; 5(1): 20–33.

[9] De Figueiredo SM, Binda NS, Nogueira-Machado JA, et al. Loftfield E, Freedman ND, Graubard BI, et al. Coffee drinking and cutaneous melanoma risk in the NIH-AARP diet and health study. J Natl Cancer Inst. 2015 Jan 20; 107(2).

[10] The antioxidant properties of organosulfur compounds (sulforaphane). Endocr Metab Immun Drug Discov. 2015; 9(1): 24-39.

[11] Grant WB, Wimalawansa SJ, Holick MF, et al. Emphasizing the health benefits of vitamin D for those with neurodevelopmental disorders and intellectual disabilities. Nutrients. 2015 Feb 27; 7(3): 1538-64.

[12] Zhu Y, Cheng Y, Luo RC, et al. Aspirin for the primary prevention of skin cancer: A meta-analysis. Oncol Lett. 2015 Mar; 9(3): 1073-1080.

[13] Powers JG, Gilchrest BA. What you and your patients need to know about vitamin D. Semin Cutan Med Surg. 2012 Mar; 31(1): 2-10.

[14] Astner S, Anderson R. Remembering Thomas B. Fitzpatrick; Skin Phototypes 2003. J Ivest Dermatol. 2004; 122: xxx–xxxi.

[15] The Unbounded Spirit. Scientists blow the lid on cancer sunscreen myth. http://theunboundedspirit.com/scientists-blow-the-lid-on-cancer-sunscreen-myth/

[16] Environmental Working Group. Sunscreen Hall of Shame. http://www.ewg.org/2015sunscreen/hall-of-shame/

[17] American Cancer Society. Learn About Cancer: Skin Cancer. http://www.cancer.org/cancer/skincancer/index

[18] Memorial Sloan Kettering. Skin Cancer. https://www.mskcc.org/cancer-care/types/skin

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