I got a lot of questions about vitamin D last week after I sent out an email examining the latest news! While the news was fresh, I did a show on vitamin D, most pertinently in regards to a question a received regarding vitamin D and cancer.
Dak writes, “Please comment on the risk on pancreatic cancer as a result of high levels of vitamin D. Vitamin D is the new vitamin E… remember that era? Turns out too much vitamin E is toxic! I question all research on vitamin D.”
I give an in-depth response in the video above, but here’s the short of it:
- Vitamin E is an antioxidant; Vitamin D is a hormone.
- Antioxidants work in ratios, hormones have single optimal ranges (conditionally-dependent).
- What is in question is What is the optimal range for serum vitamin D levels?
- Most recent research shows the greatest benefit in the greatest range of conditions at 40 – 50 ng/mL.
- Some research has tentatively shown a link between serum vitamin D and cancer.
- The reason for this link is unclear, but may be related to sun exposure and not vitamin D.
- Sun exposure increases vitamin D (which is probably good), but we know it can also cause cell damage and cancer (which is bad).
- Again, most recent research shows that vitamin D in the range of 40 – 50 ng/mL is preventative of cancer.
The other two questions are as follows:
Curious asks, “I thought vitamin D came from the sun. How can we absorb it in pill form?”
Carlos asks, “What types of vitamin D are there? How much should I take?”
In answer to Curious, vitamin D (more technically, 25-hydroxyvitamin D) is a chemical which our skin normally produces when exposed to UVB radiation. Vitamin D is synthesized from cholesterol, originally. This makes vitamin D a lipid (a fat), and like all fats, we can absorb it through our digestive system.
In the body, vitamin D goes through a number of transformations, but in the stores you’ll only see two types of vitamin D:
- Vitamin D2 (ergocalciferol)
- Vitamin D3 (cholecalciferol)
Vitamin D3 is the preferred source because it is more potent and more predictable. Vitamin D2 works, but is less predictable. The upside to D2 is that it is vegan-friendly, whereas D3 is not because it is synthesized by exposing sheep’s wool to UVB radiation–just the wool, not entire sheep!
I recommend starting with 2,000 IU per day, considering all sources. Most milks (both cow’s and plant-based) are vitamin D fortified, so count how much you typically get from milk.
After this, get a 25-hydroxyvitamin D test done–25(OH)D test for short–and work with your doctor or a nutritionist to find the right amount of supplementation to reach the optimal 40 – 50 ng/mL!
If you have any feedback, comments, or more questions about vitamin D, please post them in the comments below!
[toggle_item title=”References” active=”false”]
- Skinner HG, Michaud DS, Giovannucci E, Willett WC, Colditz GA, Fuchs CS. Vitamin D intake and the risk for pancreatic cancer in two cohort studies. Cancer Epidemiol Biomarkers Prev. 2006 Sep;15(9):1688-95.
- Stolzenberg-Solomon RZ, Jacobs EJ, Arslan AA, et al. Circulating 25-hydroxyvitamin D and risk of pancreatic cancer: Cohort Consortium Vitamin D Pooling Project of Rarer Cancers. Am J Epidemiol. 2010 Jul 1;172(1):81-93. doi: 10.1093/aje/kwq120.
- Bao Y, Ng K, Wolpin BM, Michaud DS, Giovannucci E, Fuchs CS. Predicted vitamin D status and pancreatic cancer risk in two prospective cohort studies. Br J Cancer. 2010 Apr 27;102(9):1422-7. doi: 10.1038/sj.bjc.6605658.
- Mohr SB, Garland CF, Gorham ED, Grant WB, Garland FC. Ultraviolet B irradiance and vitamin D status are inversely associated with incidence rates of pancreatic cancer worldwide. Pancreas. 2010 Jul;39(5):669-74. doi: 10.1097/MPA.0b013e3181ce654d.
- Ross AC, Manson JE, Abrams SA, et al. The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know. J Clin Endocrinol Metab. 2011 Jan;96(1):53-8. doi: 10.1210/jc.2010-2704.
- Thacher TD, Clarke BL. Vitamin D insufficiency. Mayo Clin Proc. 2011 Jan;86(1):50-60. doi: 10.4065/mcp.2010.0567.
- Ahn J, Peters U, Albanes D, et al. Serum vitamin D concentration and prostate cancer risk: a nested case-control study. J Natl Cancer Inst. 2008 Jun 4;100(11):796-804. doi: 10.1093/jnci/djn152.
- Albanes D, Mondul AM, Yu K, et al. Serum 25-hydroxy vitamin D and prostate cancer risk in a large nested case-control study. Cancer Epidemiol Biomarkers Prev. 2011 Sep;20(9):1850-60. doi: 10.1158/1055-9965.EPI-11-0403.
- Gilbert R, Martin RM, Beynon R, et al. Associations of circulating and dietary vitamin D with prostate cancer risk: a systematic review and dose-response meta-analysis. Cancer Causes Control. 2011 Mar;22(3):319-40. doi: 10.1007/s10552-010-9706-3.
- Meyer HE, Robsahm TE, Bjørge T, Brustad M, Blomhoff R. Vitamin D, season, and risk of prostate cancer: a nested case-control study within Norwegian health studies. Am J Clin Nutr. 2013 Jan;97(1):147-54. doi: 10.3945/ajcn.112.039222.