MND: If there were a “top ten” list of the most sought for nutrients today, Vitamin D and Omega 3 fatty acids would certainly fight for the number one position.
At MND, we keep an eye on the hype factor for nutrients, sometimes the good news seem compelling. Take the latest on vitamin D’s anti-cancerous properties: Nutraingredients posted on a Harvard study , Since we like to hear it from the horse’s mouth we followed the link to the study itself .
Bottom line from the Harvard study:”..Among participants in five large prospective cohorts [group of patients participating in the study], higher plasma levels of 25(OH)D were associated with a lower risk for pancreatic cancer..”
The study consisted of a pooled analysis of nested case–control studies with 451 cases and 1,167 controls from five cohorts through 2008…”
That is a good size study. So conversely, low level of Vitamin D in your blood would raise the pancreatic cancer risk. Is it true for other forms of cancer? A couple studies suggest it, but the evidence seems weak :’…Low levels of vitamin D may be associated with increased cancer incidence and mortality in men, particularly for digestive-system cancers…” The overall cancer incidence reduction was 17%
Note that  has this interesting data:”..The vitamin D supplementation necessary to achieve a 25(OH)D increment of 25 nmol/L [threshold for benefit] may be at least 1500 IU/day…”
But then having a low 25(OH)D was associated with other ills than cancer, particularly
- Multiple Sclerosis 
- Urinary Tract Infection 
- Cognition 
- Chronic Pain [7,8]
Warning: Another study sounds a caution alarm, deeming Vitamin D immunosupressive .
Since so many studies suggest that low levels of vitamin D blood serums are associated with disease risk, we are waiting for more studies showing that actual supplementation is helpful.
A Facebook comment from a reader prompted me to add this about the use of vitamin D in the form D3 or D2:
Actually, study [1,2] was about measuring the blood serum vitamin D (25OHD). Reference  shows a D3 over D2 dietary advantage in the long term absorption and manufacture of blood serum 25OHD
Talk to your Doctor
 NutraIngredients ; “Vitamin D may slash pancreatic cancer risk: Harvard study” ; 14 December 2011
 aacrj journals, Cancer Epidemiology, markers and Prevention; “Plasma 25-Hydroxyvitamin D and Risk of Pancreatic Cancer” ; Aug 30, 2011
 JNCI (Journal of The National Cancer Institute) ; “Prospective Study of Predictors of Vitamin D Status and Cancer Incidence and Mortality in Men” ; 2005
 MediNewsDigest: Urinary Tract Infections: Vitamin D could help
 MediNewsDigest: Does Vitamin D Help Chronic Pain?
 MediNewsDigest: : Chronic Pain, Gender Differences, and Vitamin D and Fish Oils Treatments (sciencedirect)
 Journal of Critical Endocrinology and Metabolism (JCEM) ; “Vitamin D2 Is Much Less Effective than Vitamin D3 in Humans” ; Nov 2004