At least one out of every two men over the age of 60 has prostate cancer, although most of these people have no symptoms. This was discovered many years ago in a study of men who had died of other reasons. Prostate cancer is typically a disease which men die with, not from! Even so, it is the second most common reason for cancer in men (after lung cancer).
Therefore, it cannot be denied that there is great need for an effective treatment, but the development of new treatments has slowed in recent years. Now there is activity in this field. More and more, prostate cancer has been associated with the extremely widespread phenomenon of vitamin D deficiency. Vitamin D normally has normalising and growth inhibiting effects in many tissue types.
Belief in vitamin D is now so large that one of the world’s leading vitamin D researchers, professor David Feldman of Stanford University, has initiated a clinical study into its effects. It is focused on men with prostate cancer who have had relapses under normal treatment.
Feldman will give them a combination of active vitamin D (calcitriol, se below) and normal NSAID pain medication (ibutamin or naproxen), both in controlled doses. To avoid side effects due to calcitriol, it will be given once weekly (the dose is not specified).
Years of laboratory studies have gone into the preparation of this study. The latest result of these lab studies is that calcitriol reduces the growth of prostate cancer by 25%. This is the same result as achieved with traditional NSAID treatment.
The most encouraging find was that when vitamin D and NSAID are combined, growth was reduced by 70%, even though tolerable doses of each substance were used. Both substances counteract the production of prostaglandins, which cause the cancer cells to grow. Prostaglandins also promote arthritis pain.
This find, as well as the announcement of the new study, was included in a press release from Stanford University. If the study lives up to its expectations it will not only have an enormous impact on treatment, but will also send a signal to healthy men to take more vitamin D, maybe much more vitamin D, so they can produce more calcitriol (calcitriol can only be purchased with a prescription).
Feldman is not just anybody when it comes to vitamin D. He and two others are behind the book “Vitamin D” (Academic Press) which, at 1,800 pages is a standard text for researchers. The newly revised edition costs about £215, so it is hardly mass market. Feldman has researched vitamin D for many years and has published more than 200 scientific articles.
Vitamin D is not a vitamin at all, but is a hormone. It is created in the skin when hit by the sun’s rays, but must be converted in the liver and the kidneys into active calcitriol. It is increasingly widely accepted that the elderly in particular cannot get enough vitamin D if they don’t take supplements are eat a lot of fatty fish. This is because as skin ages it looses its ability to produce the vitamin D. In the dark winter months of the northern climes the sun is so low in the sky that neither the young nor the old produce much vitamin D, regardless of whether or not they get some sun.
The vitamin D content of typical British food is quite low. It is recommended that adults receive 10 micrograms while the elderly should receive double that amount, and it is difficult to find researchers who disagree with these recommendations. Supplements may be necessary to achieve these values. The upper limit of risk free vitamin D intake is believed to be 50 micrograms per day.
Reference:
- Moreno J, Krishnan AV, Feldman D. Molecular mechanisms mediating the anti-proliferative effects of Vitamin D in prostate cancer. J Steroid Biochem Mol Biol. 2004 Nov;92(4):317-25
