Vitamin D And Cancer Ntr313 Power Point

Vitamin D and Cancer

Rebecca Dover, Felicia Brooks, Elizabeth Malik, John Hornung, Rebecca Willis, Morganne Phraner

Introduction  





Vitamin D is acquired primarily and most effectively through exposure to the sun by means of the skin. It is believed that Vitamin D may inhibit tumor development and growth and reduce mortality for certain cancers in the human body. Many dermatologists believe sun exposure should be minimized in order to prevent skin damage and cancer, but research has also shown that vitamin D synthesized from ultraviolet radiation actually has photoprotective effects for the skin. Even if there is a risk of skin cancer from exposure to UV radiation, though, is it not worth the risk in order to decrease internal cancer mortality by synthesizing sufficient vitamin D?

PRO 

Article #1: Solar ultraviolet-B exposure and cancer incidence and mortality in the United States, 1993-2002 – High quality and resolution data sets were used to determine cancer incidence and mortality in the US and to show how many cancers regressed in exposure to UV-B radiation. – Over three million cancer incidents between 1998 and 2002 and three million cases between 1993 and 2002 in the United States were shown to regress with daily satellite-measured solar UV-B levels. Numerous cofounders were adjusted for. – Relative risks of reduced solar UV-B exposure were calculated for 32 different cancer locations.

PRO  Results:

– Ten sites in the human body showed a decreased incidence and mortality of cancer with exposure to UV-B radiation  Bladder,

colon, Hodgkin lymphoma, myeloma, other biliary, prostate, rectum, stomach, uterus, and vulva  Weaker evidence of this same inverse relationship was apparent in breast, kidney, leukemia, non-Hodgkin lymphoma, pancreas, and small intestine.

PRO 



This article attempted to overcome some of the limitations of previous studies of this type by using both incidence and mortality data, large sample sizes, county-level geographic resolution, high-resolution solar exposure data, and adjustment for numerous confounders. Confounders included age, poverty, income, smoking, exercise, alcohol, outdoor occupation, urban/rural, and air quality.

PRO 

Findings of this article back up the common idea that optimal vitamin D synthesis from UV-B exposure decreases certain internal cancer incidence in the human body.



Maintaining adequate vitamin D levels is also important in slowing tumor progression.



The findings were consistent with similar published articles at this time, and even found new information on positive effects of UV-B for leukemia, small intestine, and vulva.

CON 

Even though there are possible benefits of prevention of internal and other cancers through sun exposure, there is also great response and consequence of affecting the skin in a negative and detrimental manner.  UV

radiation is a carcinogen responsible for most of the 1.3 million skin cancer cases in the U.S. each year.

 In

the best case scenario, UV rays will simply compromise skin appearance and elasticity.

QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.

QuickTimeª and a TIFF (Uncompressed) decompres are needed to see this picture

CON 

One study in the University of Florida was conducted with hairless mice and other animal models demonstrating this relation of skin damage repeatedly occurring since the 1920s (particularly in squamous cells).



Other studies conducted in the 1980s were of 100 healthy human volunteers and multiple narrow-band UV light sources. This study determined the relative efficacy of different wavelengths of light in producing sunburn and suntan as well as epidermal DNA damage.



Discovered that the action spectra for all these responses were strikingly similar with a peak of ~290-300nm.

CON 

Another group of researchers determined the action spectra for vitamin D synthesis in the skin in the same manner and sample size and found it to be extremely similar to that of the DNA damage with a peak of ~300nm.



Therefore, the virtual identity of these multiple action spectra implies that DNA damage is responsible for sun exposure and that vitamin D synthesis cannot occur in the absence of DNA damage.



For that reason, because UV action spectra for DNA damage, skin cancer, and vitamin D synthesis are all identical, alternative methods for acquiring vitamin D should be recommended.

PRO  In

vivo and in vitro research study:

-Vitamin D is synthesized by the same ultraviolet radiation that causes skin "mutagenic DNA damage such as cyclobutane pyrimidine dimers (CPD) and immunosuppression, both of which play a role in skin carcinogenesis” -This study showed that 1,25(OH)2D3 had photoprotective properties in skin

PRO 

How?

Samples -In vitro study- 69 human neonatal foreskins -In vivo study- live, albino, hairless mice Treatments Irradiation -Irradiance for human skin samples: 203mj/mn² UVB and 1168mj/cm² UVA -Irradiance for mouse skin samples: 3.98KJ/m² UVB and 63.8KJ/m² UVA

PRO Analysis -for sunburn, CPD damage and immunosuppression Results with application of 1,25(OH)2D3, or analog JN -Cell Death -Sunburn -CPD damage -Immunosuppression in mice Application -Photoprotective effect of 1,25(OH)2D3 -Prevention of skin cancer.

CON  Supplementation:

-Best way to ensure you meet the AI -Works regardless of variables -Daily supplements can completely compensate for lack of vitamin D synthesized in the skin -Toxicity is rare

CON 

Diet: -Vitamin D rich foods complement supplementation -Natural sources include liver, beef, eggs, dairy products, and some saltwater fish -Fortified foods include milk, orange juice, and cereal



Sunscreen: -Avoiding the sun, is the best way to protect skin cancer. Since many people love the outdoors, sunscreen is option number two. -Sun protection factor or SPF is a measure of how well sunscreen stops UVB -1/SPF photons continuously transmitted Ex: If bottle indicates SPF 15 about 1/15 or 7% photons transmitted through. -Most sunscreen users do not apply enough

Food

Cod liver oil, 1 tablespoon

IUs per Percen serving* t DV**

1,360

340

Salmon, cooked, 3.5 ounces

360

90

Mackerel, cooked, 3.5 ounces

345

90

Tuna fish, canned in oil, 3 ounces

200

50

Sardines, canned in oil, drained, 1.75 ounces

250

70

Milk, nonfat, reduced fat, and whole, vitamin D-fortified, 1 cup

98

25

Margarine, fortified, 1 tablespoon

60

15

Ready-to-eat cereal, fortified with 10% of the DV for vitamin D, 0.75-1 cup (more heavily fortified cereals might provide more of the DV)

40

10

Egg, 1 whole (vitamin D is found in yolk)

20

6

Liver, beef, cooked, 3.5 ounces

15

4

Cheese, Swiss, 1 ounce

12

4

PRO 

Current research has been done only with UV-B, UV-A, and UV-R exposure



Supplementation Risks

PRO 

The anticancer properties have been attributed primarily to calcitriol



Research shows Vitamin D acquired by the sun inhibits tumor development and growth and reduce mortality for certain cancers



Vitamin D circulating in blood benefits

PRO  Studies

accounted for variables

-Long-term vs. Short-term exposure -Socioeconomic status -Physical Activity -Geographic Locations

QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.

CON: Skin Phototypes 

Set of determinants that determine effects of UV radiation on human skin



Reflects extent of sunburning vs. subsequent tanning after an initial moderate sun exposure after a long period of little or no exposure



Affect acute and chronic risks of UV exposure and rate of Vitamin D synthesis

CON: Skin Phototypes 





Phototype I or II – Burn readily and tan minimally if at all – Achieve max Vitamin D synthesis quickly – With long exposure suffer substantial DNA damage Phototype III – Burn less and tan more easily than Phototypes I and II – Similar rates of Vitamin D synthesis and DNA damage – Tanning response dominates with repeat exposures Phototype VI – High melanin protects skin from initial DNA damage – Do not sunburn but synthesize little Vitamin D – Tan darkly with repeat exposure – Minimal photoaging and skin cancer risk

CON: Other Variables          

Skin Color Latitude Altitude Time of Day and Year Environmental Factors Elderly Homebound/Institutionalized Work Schedule Body Fat Common Medications

CON: Tanning and the Media 

Glamorous Image



Target Groups



Most responsive groups at lowest risk for Vitamin D insufficiency



Tanning beds often touted as a safe alternative

Final Words

References 



    

Boscoe, Francis P. and Maria J. Schymura. Solar ultraviolet-B exposure and cancer incidence and mortality in the United States, 1993-2002. BMC Cancer 2006, 6:264. 10 Nov 2006. Dixon, K.M., S.S. Deo, A.W. Norman, J.E. Bishop, G.M. Halliday, V.E. Reeve, R.S. Mason. In vivo relevance for photoprotection by the vitamin D rapid response pathway. Journal of Steroid Biochemistry & Molecular Biology 103 (2007) 451-456. Gropper SS, Smith JL, Groff JL. Advanced Nutrition and Human Metabolism. 4th ed. Belmont, California. Thomson Wadsworth: 2005: 343-352. Sizer F, Whitney E. Nutrition Concepts and Controversies. 9th ed. Belmont, California: Thomson Wadsworth; 2003: 213, 218-220, 245, 457-458, 494. Gilchrest, BA. Sun exposure and vitamin D sufficienty. American Journal of Clinical Nutrtion. 2008; 88: 570S-577S. The sunshine D-lemma. Harvard Health Letter. 2008; 6-7. Brown J. Nutrition Through the Life Cycle. 3rd ed. Belmont, California: Thomson Wadsworth; 2008: 16, 163, 286, 470-471.