Take Multivitamins Urges The American Medical Association
August 31,2002
Reversing a long-standing anti-vitamin policy, The Journal of the American Medical Association
(JAMA) today is advising all
adults to take at least one multivitamin pill each day.
Scientists' understanding of the benefits of vitamins has rapidly advanced, and it now appears that
people who get
enough vitamins may be able to prevent such common chronic illnesses as cancer, heart disease and
osteoporosis,
according to Drs. Robert Fletcher and Kathleen Fairfield of Harvard University, who wrote the new guidelines.
The last time JAMA made a comprehensive review of vitamins, about 20 years ago, it concluded people of normal
health shouldn't take multivitamins because they were a waste of time and money. People can get all the nutrients
they need from their diet, JAMA advised, adding that only pregnant women and chronically sick people may need
certain vitamins.
That was at a time when knowledge about vitamins was just beginning to expand. The role that low levels of folate,
or folic acid, play in neural tube defects, for instance, was not known, nor was its role as a major risk factor for heart
disease.
Researchers hope JAMA's endorsement will encourage more people to reap health benefits of a daily multivitamin.
Health experts are increasingly worried that most American adults do not consume healthy amounts of vitamins in
their diet, although they may be getting enough to ward off such vitamin-deficiency disorders as scurvy, beriberi and
pellagra.
Almost 80 percent of Americans do not eat at least five helpings of fruits and vegetables a day, the recommended
minimum amount believed to provide sufficient essential nutrients.
Humans do not make their own vitamins, except
for some vitamin D, and they must get them from an outside source to prevent metabolic disorders.
"It's nice to see this change in philosophy that's saying we can make
public-health recommendations based on this
really compelling set of data," said Dr. Jeffrey Blumberg, chief of antioxidant research at Tufts University's Jean
Mayer USDA Human Nutrition Research Center on Aging.
Blumberg said the JAMA recommendations underscore a growing concern among nutrition experts that the
recommended daily allowances, or RDAs, for many vitamins are set too low.
RDAs essentially were established to prevent symptoms of vitamin-deficiency disorders, he said. But evidence is
growing that higher levels of many vitamins are necessary to achieve optimum health, he said.
The National
Academy of Sciences, which sets RDAs, is revising its recommendations based on the new evidence.
Even people who eat five daily servings of fruits and vegetables may not get enough of certain vitamins for optimum
health, Fletcher said.
Most people, for instance, cannot get the healthiest levels of folate and vitamins D and E from
recommended diets, he said.
"All of us grew up believing that if we ate a reasonable diet, that would take care of our vitamin needs," Fletcher
said. "But the new evidence, much of it in the last couple of years, is that vitamins also prevent the usual diseases
we deal with every day -heart disease, cancer, osteoporosis and birth defects."
(1)
Actual Journal of the American Medical
Association Summary Article
Vitamins for Chronic
Disease Prevention in Adults
Scientific
Review June 19, 2002
Kathleen M. Fairfield,
MD,DrPH; Robert H. Fletcher, MD,MSc JAMA. 2002;287:3116-3126.
Context: Although
vitamin deficiency is encountered infrequently in developed
countries, inadequate intake of several vitamins is associated with
chronic disease.
Objective: To
review the clinically important vitamins with regard to their
biological effects, food sources, deficiency syndromes, potential
for toxicity, and relationship to chronic disease.
Data Sources and
Study Selection: We searched MEDLINE for English-language
articles about vitamins in relation to chronic diseases and their
references published from 1966 through January 11, 2002.
Data Extraction:
We reviewed articles jointly for the most clinically important
information, emphasizing randomized trials where available.
Data
Synthesis: Our review of 9 vitamins showed that elderly people,
vegans, alcohol-dependent individuals, and patients with
malabsorption are at higher risk of inadequate intake or absorption
of several vitamins. Excessive doses of vitamin A during early
pregnancy and fat-soluble vitamins taken anytime may result in
adverse outcomes. Inadequate folate status is associated with neural
tube defect and some cancers. Folate and vitamins B 6
and B 12 are
required for homocysteine metabolism and are associated with
coronary heart disease risk. Vitamin E and lycopene may decrease the
risk of prostate cancer. Vitamin D is associated with decreased
occurrence of fractures when taken with calcium.
Conclusions:
Some groups of patients are at higher risk for vitamin deficiency
and suboptimal vitamin status. Many physicians may be unaware of
common food sources of vitamins or unsure which vitamins they should
recommend for their patients. Vitamin excess is possible with
supplementation, particularly for fat-soluble vitamins. Inadequate
intake of several vitamins has been linked to chronic diseases,
including coronary heart disease, cancer, and osteoporosis.
Author
Affiliations: Division of General Medicine and Primary Care,
Beth Israel Deaconess Medical Center, and Channing Laboratory,
Department of Medicine, Brigham and Women's Hospital, Harvard
Medical School (Dr Fairfield); Department of Ambulatory Care and
Prevention, Harvard Medical School/Harvard Pilgrim Health Care, and
Department of Epidemiology, Harvard School of Public Health (Dr
Fletcher), Boston, Mass. (2)
Links: