Coalition for Advanced Cancer Treatment and Prevention


Search the site

Vitamin D3 Decreases Cancer Risk

and is Essential for Health

Anthony Chapdelaine, Jr., MD, MSPH, Exec. Dir./Sec.*
  • Maintaining the highest blood levels of Vitamin D3 greatly decreases cancer risk. It cuts breast cancer and colon cancer risk by nearly one-half.1, 2, 3, 4, 5
  • Vitamin D3 (cholecalciferol, the most bioactive form) is up to twice as strong as Vitamin D2 (ergocalciferol, the usual form prescribed once-a-week to patients).1
  • Vitamin D3 blood levels (25(OH)D) currently recommended (at least 30 ng/mL) are inadequate for optimal health. Vitamin D3 capsules should be given at the dose (usually measured in IUs or “International Units”) and for the length of time that is necessary to raise (and then maintain) the blood level above 50 ng/mL. The preponderance of scientific evidence shows that a level between 80 and 100 ng/mL is optimal for most people. Clinical evidence (my own and that of many other functional medicine doctors) shows that reaching this maintenance level requires a baseline blood level test and then, depending on the results, a daily Vitamin D3 supplement of 400 IUs up to 25,000 IUs for three to four weeks, followed by another blood level. Adjustments in the Vitamin D3 dose (upward or downward) every two to three months (after repeat blood level monitoring) will usually result in a stable, long-term dose which will maintain the proper blood level. This Vitamin D3 dose will need measured once a year (except for the rare individual whose levels fluctuate erratically and whose levels should be monitored more frequently).7
  • Studies show that using Vitamin D3 with calcium decreases falls and bone fractures by around 20% (while also increasing postmenopausal bone density) 7, 8, 9  (This occurs despite using minimal, inadequate doses of Vitamin D3 and almost no magnesium. By optimizing the Vitamin D3 dose, and adding absorbable magnesium and calcium, the benefits of increased bone density and reduced fractures increase tremendously.)
  • The lowest blood level (compared with the highest) of Vitamin D3 doubles the risk of heart-failure, increases the risk of stroke by nearly 80%, and increases the risk of developing coronary heart disease by nearly 50%.10, 11, 12
  • The lowest blood level of Vitamin D3 increases the risk of cognitive impairment.13  
  • Maintaining the highest blood level of Vitamin D3 decreases the risk of the flu (Influenza A infection) and childhood asthma.14
  • One study showed that a low level of Vitamin D3 decreased muscle power and force in teenage girls.15
  • Most developing fetuses are deficient in Vitamin D3, even for women taking 4000 IUs daily during pregnancy. Even so, in a double-blind, placebo-controlled study, women taking just 4000 IUs daily during pregnancy experienced one-half of the complications (preterm labor, preterm birth, infections, fetal immune deficiency) of those women taking the recommended daily dose of 400 IUs (the dose found in most daily multivitamins).16, 17
  • A recent University of California School of Medicine study showed that low sunlight (Vitamin D3) doubles the risk of leukemia (a cancer of white blood cells), and is consistent with similar studies showing the lower levels of Vitamin D3 increase risk of breast cancer and colorectal cancer.18
  • People in countries with the lowest UVB (sunlight) exposure (and therefore the lowest Vitamin D) had six times the incidence rate of pancreatic cancer compared with people with the highest UVB exposure.19
* The Coalition for Advanced Cancer Treatment and Prevention a project of The National Fund for Alternative Medicine


  1. Bauer SR, Hankinson SE, et al, “Plasma Vitamin D Levels, Menopause, and Risk of Breast Cancer: Dose-response Meta-analysis of Prospective Studies,” Medicine, 2013, 92, Pgs 123-131.
  2. Chen P, Hu P, et al, “Meta-analysis of Vitamin D, Calcium and the Prevention of Breast Cancer,” Breast Cancer Res Treat, 2010 Jun, 121(2), Pgs 469-477.
  3. Garland CF, Grant WB, et al, “What is the Dose-Response Relationship between Vitamin D and Cancer Risk?” Nutrition Reviews, 2007, 65(8), Pgs S91-S95.
  4. Jenab M, Bueno-de-Mesquita HB, et al, “Association Between Pre-diagnostic Circulating Vitamin D Concentration and Risk of Colorectal Cancer in European Populations: a Nested Case-control Study,” BMJ, 2010 Jan 21, Pg 340:b5500.
  5. Ng K, Wolpin BM, et al, “Prospective Study of Predictors of Vitamin D Status and Survival in Patients with Colorectal Cancer,” Br J Cancer, 2009 Sep 15, 101(6), Pgs 916-923.
  6. Heaney, RP, Recker, RR, et al, “Vitamin D3 Is More Potent Than Vitamin D2 in Humans,” J Clin Endocrinol Metab, 2011 Mar, 96(3), Pgs E447-E452. 
  7. Bischoff-Ferrari H, “Vitamin D: What Is An Adequate Vitamin D Level and How Much Supplementation Is Necessary?” Best Pract Res Clin Rheumatol, 2009 Dec, 23(6), Pgs 789-795.
  8. Abrahamsen B, Masud T, Avenell A, et al. “Patient Level Pooled Analysis of 68 500 Patients from Seven Major Vitamin D Fracture Trials in US and Europe,” BMJ, 2010 Jan, 340:b5463.
  9. Kärkkäinen M, Tuppurainen M, et al, “Effect of Calcium and Vitamin D Supplementation on Bone Mineral Density in Women Aged 65-71 Years: a 3-year Randomized Population-based Trial (OSTPRE-FPS),” Osteoporos Int, 2010 Dec, 21(12), Pgs 2047-2055.
  10. Parker J, Hashmi O, et al, “Levels of Vitamin D and Cardiometabolic Disorders: Systematic Review and Meta-analysis,” Maturitas, 2010 Mar, 65(3), Pgs 225-236.
  11. Ginde AA, Scragg R, et al, “Prospective Study of Serum 25-Hydroxyvitamin D Level, Cardiovascular Disease Mortality, and All-Cause Mortality in Older U.S. Adults,” J Am Geriatr Soc, 2009 Sept, 57(9), Pgs 1595-1603.
  12. Muscogiuria G, et al, “Can Vitamin D Deficiency Cause Diabetes and Cardiovascular Diseases? Present Evidence and Future Perspectives,” Nutr Metab Cardiovasc Dis, 2012, 22(2), Pgs 81-87.
  13. Llewellyn DJ, Langa KM, Lang IA, “Serum 25-hydroxyvitamin D Concentration and Cognitive Impairment,” J Geriatr Psychiatry Neurol, 2009 Sep, 22(3), Pgs 188-195.
  14.  Urashima M, Segawa T, et al, “Randomized Trial of Vitamin D Supplementation to Prevent Seasonal Influenza A in Schoolchildren,” Am J Clin Nut, 2010 May, 91(5), Pgs 1255-1260.
  15. Ward KA, Das G, et al, “Vitamin D Status and Muscle Function in Post-Menarchal Adolescent Girls,” J Clin Endocrin Metab, 2009, 94(2), Pgs 559-563.
  16. Hollis, BW, Johnson, D, et al, “Vitamin D Supplementation During Pregnancy: Double Blind, Randomized Clinical Trial of Safety and Effectiveness,” J Bone Miner Res, 2011 Oct, 26(10), Pgs 2341–2357.
  17. Wagner CL, Taylor SN, et al, “Vitamin D and Its Role During Pregnancy in Attaining Optimal Health of Mother and Fetus,” Nutrients, 2012 Mar, 4(3), Pgs 208–230.
  18. Cuomo RE, et al, “Cloud Cover-Adjusted Ultraviolet B Irradiance Is Associated with High Incidence Rates of Leukemia: Study of 172 Countries,” PLoS ONE, 2015, 10(12), e0144308,  doi:10.1371/journal.pone.0144308.
  19. Garland CF, et al, “Cloud cover-adjusted ultraviolet B irradiance and pancreatic cancer incidence in 172 countries,” J Steroid Biochem Mol Biol, 2016 Jan, 155(Pt B), Pgs 257-263.