Vitamins: Do they really help?
Many Canadians think so, but experts warn about excessive amounts
Karen Sievwright of Stony Plain, Alta., believes in a wellrounded, healthy diet for her three children. But she’s also convinced their daily dose of multivitamins gives them a special advantage.
While other children typically get several colds a year, Sievwright says her kids breeze through only one or two shorter-lasting viruses, and her oldest son seems to heal himself when he gets an ear infection.
Sievwright’s belief in the power of supplements is far from unusual: An estimated 14 million Canadians — children and adults — take vitamins, contributing to sales of about $370 million a year. And those numbers are climbing steadily, according to the market-research firm Euromonitor International.
But a number of recent studies suggest that while our belief in the power of vitamins keeps growing, evidence that they do anything to boost the health of people who don’t suffer from vitamin deficiencies is shrinking. At a certain point, some might actually do harm.
In her new book Vitamania: Our Obsessive Quest For Nutritional Perfection, U.S. journalist Catherine Price traces the fascinating history of the vitamin.
Until the mid-1800s, the disease known as scurvy took a tremendous toll, killing more than two million seamen, beginning with symptoms that included sore gums and loose teeth.
It wasn’t until a doctor conducted possibly the world’s first clinical trial — putting groups of sailors on different “treatments” and seeing how they fared — that citrus fruit was confirmed as a preventive. At the time, no one knew about vitamin C.
In the early 20th century, researchers pinpointed the underlying trigger for illnesses including beriberi and pellagra by identifying 13 compounds crucial to regulating metabolic activity and other cellular processes, mostly obtained by humans from food — and a major problem if missing.
Consumers have long been dazzled by vitamins’ “magical-seeming powers,” she said, citing the squirt of vitamin A that restores sight to blind, malnourished children in parts of Africa.
But our love affair with vitamins seems built on something more: the notion that adding to our minimum required intake will lead to added benefits — including everything from mood enhancement to longevity.
The discovery of vitamins was also a marketing gold mine from the start. As Price writes, in the 1930s, it led to vastly increased sales of iceberg lettuce, which contains vitamins A and K, though little else of value.
The milling that produces white flour and white rice and sterilization that makes packaged products safe removes the very parts of those foods that contain lifesustaining vitamins.
The solution? Synthetically produced versions are routinely added back in to the nutrient-stripped food, from bread to lowfat milk and fruit drinks.
Regardless, the consumption of vitamin supplements — taken on top of those added to a vast range of foods — has grown.
In addition to all but eliminating (in the industrialized world, at least) vitamin-deficiency diseases, this has led to some real triumphs. Fortifying flour with folic acid and encouraging pregnant women to take folic-acid pills, has dramatically reduced the rate of neural-tube birth defects, which leave babies with conditions like spina bifida.
Vitamin D is considered an important supplement for protecting women’s bone health, while promising but not definitive studies have suggested it could have other benefits.
Supplements act as a “bridge,” says Helen Long, president of the Canadian Health Food Association. “These are precisely the people who stand to benefit from natural health products,” she said in an emailed statement.
Concerns are also surfacing around the safety of consuming too many supplements. Rima Rozen is a McGill University geneticist investigating the dangers of excessive amounts of folic acid. She and her colleagues have just published studies looking at the impact of high doses — finding that 10 times the recommended daily intake of the vitamin, often the dose doctors recommend for pregnant women, causes liver damage in mice.