Donald L Trump, M.D.
Roswell Park Cancer Institute Buffalo, NY
Several months ago I discussed the data – and my biases – regarding vitamin D deficiency and insufficiency and the role optimal vitamin D might play in overall health, prostate cancer prevention and treatment. Since this is an evolving area gaining much attention I thought it might merit an update. What is the “right dose” of vitamin D supplementation? As in many areas of vitamin D biology, there is considerable debate about the answer to this question. And in prostate cancer almost no data! The U.S. recommended daily allowance (RDA) is 400 IU of vitamin D3 (cholecalciferol). This RDA is determined largely by what amount is very, very safe and prevents rickets in children. Several studies confirm that 400 IU does not change the blood 25(OH) D3 level [the blood measure of vitamin D “stores”]. For example, studies in women (The Women’s Health Initiative) randomly assigned more than 36,000 women to placebo or 400 IU of vitamin D3 +/- calcium which found no change in incidence of breast or colorectal cancer – and no change in 25(OH) vitamin D levels, before and after 400 IU of cholecalciferol.
Lappe and colleagues have recently shown that women taking 1100 IU D3 per day have fewer cancers diagnosed than women taking placebo. Vieth and colleagues in Toronto found in a small study (15 patients) that men with prostate cancer had a slower rate in rise of PSA after beginning 2000 IU/d than before1 . It is clear that people respond differently to different doses of D3 and we’re just beginning to understand the reasons for these differences. Among the differences are place of residence and activity – both likely related to sun exposure, other medications (we’ve recently found that patients taking chemotherapy for colorectal cancer require higher doses of supplementation). Other factors are just being delineated. Hollis and colleagues have suggested that if you want everyone in a population to have a 25 (OH) D level >32 ng/ml – everyone should take 4000 IU per day. A group of scientists who are vitamin D experts have recommended recently that 2000 IU is the dose we all should take (and it’s what I take – while I await my follow-up 25 (OH) D3 level [see below]. I asked my doctor to measure my 25 (OH) vitamin D level, what should it be? Here’s another area of debate. The “traditional” answer has been that individuals with a 25 (OH) D3 level ≤ 25 ng/ml are “deficient.” However, if you examine the relationship between blood parathyroid hormone (PTH) level (a hormone that is suppressed when 25(OH) D3 levels increase) and 25(OH) D3 level you find that statistically you need a 25(OH) D3 level ≥ 32 mg/ml to maximally suppress the PTH level. Similarly, bone density increases in populations of people as the 25(OH) D3 level increases – until you get to 32ng/ml. So – I believe that 32 ng/ml is the defensible lower limit of “normal.” Values lower than 32 ng/ml are deficient in my view. Raising 25(OH) D3 level higher does not improve things we know are vitamin D responsive. I believe that for some individuals higher blood levels are better. And since there are considerable data from the lab that higher exposure to vitamin D suppresses cancer growth, I recommend to my patients with a diagnosis of prostate cancer that they keep their 25(OH) D3 level in the high-normal range. The normal range of 25(OH) D3 is 32-100 ng/ml. For my prostate cancer patients I “aim” for 70-100 ng/ml – based on absolutely no information that this level is better. But I am confident it’s safe.
My recommendations are:
• Measure your vitamin D (25[OH] D3 ) level
• Take supplemental vitamin D (D3 ) to get your 25(OH) D3 level > 32 ng/ml
• Monitor every 3-6 months while you are adjusting your dose (it takes 3 months for a given dose to “equilibrate”)
I measured my own 25(OH) D3 about 3 months ago – for the first time. I am a healthy fairly active, golf loving 63 year old male who lives in Buffalo, NY – my level – in June was 24 ng/ml. I am taking 2000 IU and will measure my 2nd level next week!
1: 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 Jun;85(6):1586- 91. Erratum in: Am J Clin Nutr. 2008 Mar;87(3):794.
2: Woo TC, Choo R, Jamieson M, Chander S, Vieth R. Pilot study: potential role of vitamin D (Cholecalciferol) in patients with PSA relapse after definitive therapy. Nutr Cancer. 2005;51(1):32-6.