> Food and Nutrition > Vitamins

Nutrients In the News
by author Michelle Hancock

There have been 32 adverse reactions to vitamin C as of May 2008, according to the Canada Vigilance Online Database hosted by Health Canada. But hold on! Before you get nervous and chuck out the bottle that you just bought, let’s dig deeper.

Between 1965 and 2008–a span of more than 30 years–32 suspected adverse reactions have been reported that are associated with the hundreds, if not thousands, of different vitamin C products that have been on the market during that time.

These reactions have occurred in all age groups of the more than 71 percent of Canadians (23 million) who currently use natural health products.

These statistics have a few holes. The reporting of adverse reactions is voluntary and under-reporting is common, not only for natural health products but for pharmaceutical drugs as well. A Health Canada employee told alive that although they are working to improve their system using a recently upgraded database, current data still represents only suspected incidents. These are based on the reporter’s impressions and thoughts; they are not confirmed by investigators, and they are not causal links.

Most vitamin C-related reactions occur in people who are combining natural health products or taking natural health products with pharmaceutical medications. This makes investigation much more difficult, since the cause may be any number of things.

Suddenly, vitamin C is starting to sound relatively innocuous, isn’t it?

This breakdown shows how easy misinterpretation is at first glance and–for a consumer–how difficult it can be to get the real story.

Gimme an A for Antioxidants

Should I be taking antioxidants? This is a question that you may have asked yourself after a study in The Journal of the American Medical Association (2007) reported that antioxidants such as vitamins A and E may “significantly increase mortality.”

This meta-analysis, which also questioned vitamin C’s benefit in the reduction of mortality rates, received impressive media coverage.

But Dr. Balz Frei, professor and director of the Linus Pauling Institute at Oregon State University–a leading orthomolecular research centre–called it “a flawed analysis of flawed data” because it focused on a small group of trials. It disregarded the predominantly opposite conclusions of a vast amount of positive data from laboratory, animal, and human observational and experimental studies.

“Instead of causing harm, the totality of the evidence indicates that antioxidants from foods or supplements have many health benefits, including reduced risk for cardiovascular disease, some types of cancer, eye disease, and neurodegenerative disease,” he stated in an Oregon State University press release. “In addition, they are a key to an enhanced immune system and resistance to infection.”

Of the 815 antioxidant trials the researchers considered, only 68 were used in the analysis, noted Frei. Two especially important, but rejected studies, found substantial benefits and reduced mortality from the intake of antioxidant supplements.

Frei said that all the new study really demonstrated was “a bias toward identifying studies or research that shows harm caused by antioxidants, and selective removal of research that shows benefits.”

Gimme a B for Bias

We get messages from the media, our friends, our family members, and our neighbours down the street, each of whom has a bias.

According to a new study, so do medical journals.

In 2007 University of Florida researchers examined the relationship between drug advertising and medical journals’ publication of articles about nutritional supplements. Researchers looked at one year of the issues of 11 major medical journals to analyze pharmaceutical advertising and content about dietary supplements. The results revealed that “Increased pharmaceutical advertising is associated with publishing fewer articles about dietary supplements and publishing more articles with conclusions that dietary supplements are unsafe.”

Will this hypothesis stand the test of time? Maybe, but it won’t be the first study to be called into question.

One of the criticisms directed at the $2.5 billion industry, comprised of about 50,000 natural health products in Canada, is that the science isn’t there to support their claims. While that may sometimes be true, times are changing–fast.

Like Penelope Marrett of the CHFA, Vancouver writer Michelle Hancock has been fed a multivitamin since she was a kid. michellehancock.ca

Source: alive #310, August 2008