March 6, 2012
The Scientist: Vitamin D on trial
This is a solid piece on TheScientist online.
Subhead: “Prevention trials for vitamins and supplements are notoriously difficult, but some researchers aren’t giving up on finding proof that vitamin D helps ward off disease.”
Excerpt:
And it seems the public isn’t waiting for clinical trial data. Spurred by headlines about its potential benefits, US consumer sales of vitamin D supplements rocketed from $50 million in 2005 to $550 million in 2010, according to estimates from the Nutrition Business Journal. Enthusiasm for the vitamin echoes among doctors and natural-food advocates, who are pushing for doses higher than the 400 to 600 International Units (IU) that the government currently recommends for maintaining healthy bones.
However, (epidemiologist JoAnn Manson at Harvard Medical School), a refined woman of measured words, is acutely aware of the disappointment that has trailed the hyping of vitamins over the decades. Vitamin E, a fat-soluble antioxidant, gained a reputation for fighting cancer in the 1990s, when observational studies found that people who took supplements had lower rates of the disease. But the buzz died out in 2008 when a 35,000-person clinical trial on vitamin E and selenium was terminated prematurely after people taking the supplements showed a slightly higher risk of developing prostate cancer than the control group. Similarly, in 1996 two large clinical trials dumbfounded fans of beta-carotene, a substance that humans convert into vitamin A after consuming it in fruits and vegetables. One trial found that it raised the risk of lung cancer and heart disease, and the other ended anticlimactically after 12 years with the conclusion that beta-carotene supplements performed no differently than placebo. “You have to look at these previous randomized trials as cautionary tales,” Manson says, “because they show that time and time again, everyone jumped on the bandwagon and then the randomized trials did not have favorable results, and in fact, the risks outweighed the benefits.”
Towards the end of a wonderfully-detailed piece, there is this chart that could be a reminder for many journalists on the pitfalls of many studies.
Potential trial pitfalls
Critics of vitamin D trials worry about the following drawbacks common to prevention trials of nutrient supplements.
- Dose too small
- Dose too risky
- Outcomes too uncertain (an increased risk of disease, rather than the disease itself)
- Too little time
- Too few participants
- Incorrect treatment regimen
- Poor compliance
- Cherry-picked participants
Comments
Please note, comments are no longer published through this website. All previously made comments are still archived and available for viewing through select posts.
Comments are closed.
Our Comments Policy
But before leaving a comment, please review these notes about our policy.
You are responsible for any comments you leave on this site.
This site is primarily a forum for discussion about the quality (or lack thereof) in journalism or other media messages (advertising, marketing, public relations, medical journals, etc.) It is not intended to be a forum for definitive discussions about medicine or science.
We will delete comments that include personal attacks, unfounded allegations, unverified claims, product pitches, profanity or any from anyone who does not list a full name and a functioning email address. We will also end any thread of repetitive comments. We don”t give medical advice so we won”t respond to questions asking for it.
We don”t have sufficient staffing to contact each commenter who left such a message. If you have a question about why your comment was edited or removed, you can email us at feedback@healthnewsreview.org.
There has been a recent burst of attention to troubles with many comments left on science and science news/communication websites. Read “Online science comments: trolls, trash and treasure.”
The authors of the Retraction Watch comments policy urge commenters:
We”re also concerned about anonymous comments. We ask that all commenters leave their full name and provide an actual email address in case we feel we need to contact them. We may delete any comment left by someone who does not leave their name and a legitimate email address.
And, as noted, product pitches of any sort – pushing treatments, tests, products, procedures, physicians, medical centers, books, websites – are likely to be deleted. We don”t accept advertising on this site and are not going to give it away free.
The ability to leave comments expires after a certain period of time. So you may find that you’re unable to leave a comment on an article that is more than a few months old.
You might also like