According to CBS resident doctor David Agus yesterday, all the "data" now show vitamin D to be useless in lowering blood pressure (hmmm... never used it for that anyway) and also to be a high risk factor in causing osteoporosis as well as atherosclerosis (hardening of the arteries). He suggested to the CBS Early Morning news hosts that it would be best to stop taking the supplement entirely because of these adverse effects and that it doesn't appear to do any good, period.
Not so fast there. The Canadians, for their part, aren't ready to jump on the anti-Vitamin D bandwagon and Canada recognizes the importance of vitamin D in the prevention of osteoporosis.
Other Canadian sites warn of the 'low quality data and evidence" for the studies such as Agus cites,. In one of the BMJ studies( British Medical Journal) researchers evaluated the results of 268 previous studies and concluded: "highly convincing evidence of a clear role of vitamin D does not exist for any outcome, but associations with a selection of outcomes are probable". So no solid or uncontestable proof vitamin D helps.
The other BMJ study led by Rajiv Chowdhury cardiovascular epidemiologist at the University of Cambridge, showed that low blood levels of vitamin D are linked to increased risks of dying prematurely from cardiovascular disease, cancer, and other causes. But whether supplementation with vitamin D can help people live longer and healthier requires more study.
Indeed - and the dose levels are a seeming "mystery" as well. The unfortunate fallout from this - as with the niacin finding- is that it's thrown many supplement takers and physicians into turmoil about what to do and what advice to give.
I found the take of Howard LeWine, Chief Medical Editor for Harvard Health Online Publications to be sensible and objective, e.g.
"I plan to keep advising my patients to get the amount of vitamin D recommended by the Institute of Medicine:
- 600 IU of vitamin D a day for everyone ages 1 to 70
- 800 IU of vitamin D a day for those 71 and older
Food is usually the best way to get vitamins. But not vitamin D. Only a few foods—salmon, tuna, sardines, milk, fortified cereals, and some types of mushroom—can give you more than 100 IU per serving."
The problem again, is that to get the normal daily allottment, vast quantities of salmon, milk, tuna, mushrooms etc. would have to be consumed each day - at least much more than most people would tolerate. Hence, it is nonsense - as Agus prescribes - for people to just grab the needed amounts from food sources. It's as dumb as asserting people need to get all their calcium from the current nutrient-diluted broccoli etc. on offer by our corporate factory farms.
What about - as Agus also prescribes - just getting out into the Sun to get your quota? Not so easy. As Dr. LeWine puts it:
" It’s a hot-button issue—and a balancing act. Getting 10 to 15 minutes of sunlight on your face, arms, back, or legs without sunscreen a few times a week is enough to generate your body’s vitamin D needs for a week. But too much exposure to the sun causes skin cancer."
I can certainly vouch for that, having had two cancerous lesions already removed from my neck and chest. Also, given that I work mostly indoors, blogging - writing books etc. - I face the same sunlight deficiency many other web freaks do. The way to solve that is taking a vitamin D supplement. I had been taking 1000 iu a day, but will probably now decrease that to 600 iu as per the Harvard doc's recommendations.
But cut it out entirely based on "low quality evidence"? Not a chance!
Dr. LeWine's final advice is one which I have no problem adopting, or circulating:
"If you rarely get out in the sun, or just aren’t certain you are getting 600 to 800 IU of vitamin D a day, taking a supplement containing 400 to 1,000 IU is safe, inexpensive insurance."