Cancers and Vitamin D Council
Dr. Grant wrote excellent overviews of Vitamin D and many cancers Aug 2011
Each Overview has a patient-friendly introduction followed by lots of details and references
Update 2015
Vitamin D Council moved their Patient Overviews to a different location and eliminated many
Breast cancer*
Cervical cancer
Colorectal cancer*
Endometrial cancer
Esophageal cancer
Gastric cancer
Leukemia
Lung cancer
Melanoma
Ovarian cancer
Pancreatic cancer
Prostate cancer*
Renal cancer
See also VitaminDWiki
Update Blog post also by Dr. Grant Sept 2011 CLICK HERE for blog with hyperlinks and references
Reanalysis of randomized controlled trial shows reduced risk of cancer in vitamin D and calcium supplementation
Posted on September 7, 2011 by Dr William Grant
Those involved in setting health policy for oral vitamin D intake (IOM) have been saying that until there are more randomized controlled trials (RCTs) reporting beneficial effects, they are unwilling to accept other evidence showing beneficial effects of vitamin D for non-skeletal health conditions [Ross, 2011]. To date, we have three RCTs on whether vitamin D plays a role in preventing cancer.
One RCT on the matter showed a beneficial effect in vitamin D reducing the risk of cancer, reporting a 77% reduced risk of all-cancer incidence between the ends of the first and fourth years of 1100 IU/day vitamin D3 and 1450 mg/day calcium supplementation [Lappe, 2007]. The IOM chose not to accept this study as basis for new recommendations.
However, the IOM accepted an RCT from the Tufts Evidence-based Practice Center [Chung, 2009], based on a full four year study. The IOM report stated:
- “One RCT showed no effect of combined vitamin D3 (1000 IU/day) and calcium (~1500 mg/day) supplementation versus calcium supplementation (~1500 mg/day) alone on the risk of total cancer in healthy postmenopausal women (>55 years old) living in Nebraska (latitude 41°N).”
The largest RCT to date using vitamin D and calcium was the Women’s Health Initiative (WHI). It gave women 400 IU/day vitamin D3 and/or 1500 mg/day calcium or a placebo. Initially, researchers concluded that no beneficial effects were found for the entire set of participants for colorectal cancer [Wactawski-Wende, 2006], breast cancer [Chlebowski, 2008], any other cancers or all cancers combined [Brunner, 2011].
Bolland et al found that a subset of the participants in the WHI, those who had not taken vitamin D or calcium supplements prior to enrollment in the study, showed a reduced risk in breast cancer, colorectal cancer, and total cancer incidence.
However, a group of researchers led by Mark J Bolland recently reexamined the data set from the WHI study and found promising data. They found that a subset of the participants, those who had not taken vitamin D or calcium supplements prior to enrollment in the study, showed a
18% (95% confidence interval, -30%, -3%) reduced risk in breast cancer,
17% (-40%, +15%) in colorectal cancer, and
14% (-22%, -4%) in total cancer incidence [Bolland, 2011].
The results for breast and total cancer are considered significant, while that for colorectal cancer is not.
Thus, there are now two RCTs supporting the role of vitamin D and calcium in reducing the risk of cancer [Bolland, 2011; Lappe, 2007]. While neither RCT clearly separated the effects of vitamin D and calcium, the two RCTs can be considered as experimental support for the UVB-vitamin D-cancer hypothesis [Grant, 2009].
The relationship between vitamin D blood levels and incidence of cancer shows that cancer risk drops rapidly in individuals who increase their low vitamin D levels. Even in individuals with relatively high vitamin D levels, the cancer risk drops with further increased blood levels, albeit at a slower rate [Abbas, 2009; Grant, 2010]. Based on the serum blood level-cancer incidence rate relationship for breast and colorectal cancer [Grant, 2010], blood levels above 40 ng/ml (100 nmol/L) may reduce the risk of total cancer by about 25% [Giovannucci, 2006; Grant, 2010; Grant and Garland, 2006].
Note that between the two beneficial RCTs, the benefit of 1100 IU/day vitamin D3 was much higher than for 400 IU/day, even though those in the Lappe [2007] study started near 30 ng/ml and increased to near 40 ng/ml.