A panel of medical and nutritional professionals has rebuked an
essay published in the February 28 issue of the JAMA (Journal
of the American Medical Association), which claimed that
taking vitamins increases the risk of death.
Gathered at a recent symposium on vitamin C, the experts agreed
that a balanced intake of vitamins and minerals is actually
beneficial, not harmful, to one's well-being.
The group said that the study by Serbian doctor Goran
Bjelakovicon was "biased and selective".
Dr Hong Zhaoyi from Shanghai's Xinhua Hospital said that many of
the test subjects were suffering from serious diseases, such as
cancer and vascular disease, which invalidated the findings.
He said the test would have produced very different results if
it had used healthy people. In addition, he said that no systematic
analysis was carried out to determine the causes of death.
Yin Shi'an, director of the Children's and Women's Nutrition
Office, part of the China Disease Control Center, also expressed
his concerns regarding the validity of the results: "Members of the
test group were given higher than recommended doses of vitamin
supplements," he said.
Doctor Balz Frei of Oregon State University in the United States
said that a person's daily intake of vitamin C should not exceed 2
grams.
The study's hypotheses that vitamin intake can lead to conditions
such as increased oxalate and kidney stone formation, as well as
uric acid concentrations, were unfounded, Frei said.
While a daily intake of more than 2 grams might lead to symptoms
like diarrhea or gastrointestinal disturbances, these are not
serious, especially as vitamin C is water-resolvent and is
discharged through urine, Frei said.
(China Daily March 16, 2007)