D Vitamini ve Kanserden Korunma

Öz

D vitamini, esas olarak kemik sağlığı için gerekli olmakla birlikte vücutta birçok olayda rol oynayan, yağda çözünen vitaminler grubundan bir bileşiktir. Güneşten gelen ultraviyole ışınlarına maruziyet sonucu vücutta endojen olarak üretilebilen D vitamini, aynı zamanda bazı besinlerde doğal olarak bulunmakta veya D vitamini takviyelerinden elde edilebilmektedir. D vitamini uzun yıllardır bilinen görevlerinin yanı sıra, son yıllarda kanser, diyabet, kalp hastalıkları gibi bazı hastalıklardan korunmadaki etkisiyle de sıkça gündeme gelmektedir. Yapılan bazı araştırmalarda; güneşe maruziyetin az olduğu bölgelerde bazı kanser türlerinin daha sık görüldüğünün gözlenmesi, D vitamininin kanserden korunmada etkili olduğu düşüncesini doğurmuştur. Yapılan laboratuvar çalışmalarında, D vitamininin kanserden korunmada etkili olabileceğine dair güçlü kanıtlar elde edilse de; randomize klinik çalışmaların sonuçları çelişkilidir. D vitamini; hangi dozlarda yararlı, hangi dozlarda zararlı, hangi kanser türlerinde etkili, net olarak bilinmemektedir. Bu noktada, iyi tasarlanmış kapsamlı çalışmalara ihtiyaç vardır. Yapılacak çalışmalar için anahtar; bazı kanser türlerinin riskini azaltan, ancak diğerlerinin riskini artırmayan ideal D vitamini miktarının belirlenmesi olacaktır

Anahtar Kelimeler

• D vitamini, Kanser, Kanserden korunma, Kemoprevensiyon

Vitamin D and Cancer Prevention

Abstract

Vitamin D is essential for bone health, and is a compound in the group of fat-soluble vitamins, which plays a role in many events in the body. Vitamin D can be produced as an endogenous substance in the body as a result of exposure to ultraviolet radiation coming from the sun and is also available in certain natural foods or can be obtained from vitamin D supplements. Besides its duties that have been known for years, Vitamin D has been of interest in recent years due to its role in protection against some diseases such as cancer, diabetes, and heart disease. The idea that vitamin D is effective in protection against cancer was born as a result of the fact that certain types of cancer were observed to be more commonly encountered in regions where sun exposure was low in some studies. Although strong evidence has been obtained that vitamin D is likely to be effective in protection from cancer, the results of randomized clinical studies are inconsistent. Vitamin Dʼs beneficial and harmful doses, and the types of cancer on which it is effective, are not clearly known. At this point, well-designed comprehensive studies are needed. The key for the further studies will be the determination of the ideal amount of vitamin D that will reduce the risk of some cancers but will not increase the risk of some others

Keywords

• Vitamin D, Cancer, Cancer prevention, Chemoprevention

References

1. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010.
2. Parfitt AM. Osteomalacia and related disorders. In: Avioli LV, Krane SM, eds. Metabolic bone disease and clinically related disorders. 2nd ed. Philadelphia: WB Saunders, 1990; 329-96.
3. DeLuca HF, Zierold C. Mechanisms and functions of vitamin D. Nutr Rev 1998; 56:4-10.
4. Cranney A, Horsley T, O’Donnell S, Weiler H, Puil L, Ooi D, Atkinson S, Ward L, Moher D, Hanley D, Fang M, Yazdi F, Garritty C, Sampson M, Barrowman N,Tsertsvadze A, Mamaladze V. Effectiveness and safety of vitamin D in relation to bone health. Evid Rep Technol Assess (Full Rep) 2007; 158:1-235.
5. Ovesen L, Brot C, Jakobsen J. Food contents and biological activity of 25-hydroxyvitamin D: A vitamin D metabolite to be reckoned with? Ann Nutr Metab 2003; 47:107-13.
6. Scarlett WL. Ultraviolet radiation: Sun exposure, tanning beds, and vitamin D levels. What you need to know and how to decrease the risk of skin cancer. J Am Osteopath Assoc 2003; 103:371-5.
7. U.S. Department of Agriculture, Agricultural Research Service. 2011. USDA National Nutrient Database for Standard Reference, Release 24. Nutrient Data Laboratory Home Page, http://www.ars.usda.gov/ba/ bhnrc/ndl.
8. Apperly FL. The relation of solar radiation to cancer mortality in North America Cancer Res 1941; 1:191-5.

9. Giovannucci E. Vitamin D status and cancer incidence and mortality. Adv Exp Med Biol. 2008; 624:31-42.
10. Garland, CF, Gorham ED, Lipkin M, Newmark H, Mohr SB, Holick MF. The Role of Vitamin D in cancer prevention. Am J Public Health 2006; 96:252-61.
11. Lieberman DA, Prindiville S, Weiss DG, Willett W; VA Cooperative Study Group 380. Risk factors for advanced colonic neoplasia and hyperplastic polyps in asymptomatic individuals. JAMA 2003; 290:2959-67.
12. Lappe JM, Travers-Gustafson D, Davies KM, Recker RR, Heaney RP. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. Am J Clin Nutr 2007; 85:1586-91.
13. Freedman DM, Looker AC, Chang SC, Graubard BI. Prospective study of serum vitamin D and cancer mortality in the United States. J Natl Cancer Inst 2007; 99:1594-602.
14. Helzlsouer KJ; VDPP Steering Committee. Overview of the Cohort Consortium Vitamin D Pooling Project of Rarer Cancers. Am J Epidemiol 2010; 172:4-9.
15. Grotsky DA, Gonzalez-Suarez I, Novell A, Neumann MA, Yaddanapudi SC, Croke M, Martinez-Alonso M, Redwood AB, Ortega-Martinez S, Feng Z, Lerma E,Ramon y Cajal T, Zhang J, Matias-Guiu X, Dusso A, Gonzalo S. BRCA1 loss activates cathepsin L-mediated degradation of 53BP1 in breast cancer cells. J Cell Biol 2013; 200:187-202.
16. Sperati F, Vici P, Maugeri-Saccà M, Stranges S, Santesso N, Mariani L, Giordano A, Sergi D, Pizzuti L, Di Lauro L, Montella M, Crispo A, Mottolese M, Barba M. Vitamin D supplementation and breast cancer prevention: A systematic review and meta-analysis of randomized clinical trials. PLoS One 2013; 22:8.
17. National Cancer Institute, Cohort Consortium Projects, Active Projects and Working Groups, Vitamin D Pooling Project of Breast and Colorectal Cancer. http://epi. grants.cancer.gov/Consortia/cohort_projects.html