In one retrospective study looking at Medicare records, researchers could find no link between Vitamin D deficiency and macular degeneration. Based on this study, if you are self-prescribing Vitamin D to treat your macular degeneration, I would strongly consider stopping.
The second study involved men with prostate cancer who are on hormone depleting therapy. This therapy can lead to osteoporosis so it was always thought wise for these men to supplement with Vitamin D and calcium. This study shows that not only doesn't adding these two supplements help, but they may actually be increasing the severity of the cancer. That's on top of the calcium's effects on adding to the risk of calcification of the arteries and heart attacks.
So based on this information you would say that it is probably best to avoid Vitamin D supplements. But wait, there's more. In April 2012, a study showed that high dose Vitamin D supplementation in patients with low risk prostate cancer seemed to help the patients do better with lower Gleason scores, one of the biomarkers for prostate cancer. But wait again. In this study, involving 52 patients, led by D.T. Marshall of the Medical University of South Carolina and colleagues, 55% did better, 11% had no change, and 34% did worse.
My read on such a study is to basically ignore it because the number of participants was too low, a good percentage got worse and we know little else about their diets, etc.
So what's the answer on Vitamin D? I say sun. It's the only natural way to increase your Vitamin D levels. Of course, don't burn yourself, but 15-30 minutes a day strategically spread out should avoid any such problems in most people. However, that may not be YOU, so if you can't spend even that amount of time in the sun, your next best choice is wild salmon. If you can't or refuse to eat wild salmon, then fortified foods are your next best choice before supplements.
Yesterday, I reviewed 300 study headlines on supplements, particularly about their antioxidant effects, on pubmed.com, and read about 40 abstracts of some of the studies. This effort fortifies my belief that supplements just aren't cracked up to be what their manufacturers and marketers want YOU to believe.
But I also confirmed something else. The studies showed consistently that even with fruits and vegetables, once your body has the vitamins, minerals, and nutrients it needs, giving it more does nothing. It's like filling a canister. Once it's filled, any more added is just spillover. The principle here is that more of a good thing is not better when it comes to your nutritional state. That's the biggest problem I think posed by most supplement products. They operate mostly on the principle of get more to play it safe. More vitamins, more minerals, more antioxidants. YOU don't need more that YOU need and as recent studies suggest, more may not be safe for YOU.
The real take away from all three studies quoted above is that Vitamin D supplementation may not be the panacea that many proclaim it is on a daily basis. Tread cautiously, my friends, when it comes to taking supplements and heed the Latin phrase, Caveat Lector, "Let the reader beware." That includes reading my blog with a bit of caution as well. Nothing written here should be construed as medical advice. The only medical advice you should heed is from a doctor that knows your medical history personally and discusses treatment with YOU directly.