Why Your Vitamins Aren't Working

With promises to boost health and prevent chronic diseases, supplements can seem like an over the counter cure-all. Consumers more than buy into that notion: Vitamins accounted for roughly one-third of the $23.7 billion spent on supplements in 2007, according to the Nutrition Business Journal.

While a handful of studies have demonstrated a strong link between certain supplements and positive health outcomes, there's still limited clinical evidence to support the notion that they are critical to excellent health. In fact, much of that $23.7 billion could have been a waste of money, according to recent research.

In a study released last week in the Archives of Internal Medicine, researchers found that multivitamin use in post-menopausal women neither increased nor decreased risk of cardiovascular diseases or common cancers. And last fall, a major study of almost 35,000 men found no link between vitamin E and selenium supplements and prostate cancer prevention.

Dr. Marian L. Neuhouser, the lead author of the multivitamin study and an associate member of the Fred Hutchinson Cancer Research Center in Seattle, says that while fruits, vegetables and whole grains have been linked to good health and prevention of cancer and cardiovascular disease, that doesn't mean vitamins extracted from those food groups will have the same effect.

Scientists still aren't sure why studies of supplement use don't always mirror what we know to be true about dietary vitamin intake--that it's essential to good health. One reason is that it's very difficult to separate cause from effect. Healthier people tend to take vitamins, but that's not enough proof to establish a definitive link between supplements and optimal health.

"Each consumer needs to decide their own health practices," says Neuhouser. But "they're missing a lot if they think [vitamin] substitution will do the trick."

What the Body Needs
The body requires 13 vitamins and 15 minerals to function properly. Among the necessary vitamins are B6, which maintains brain function; biotin, which is essential for metabolism; and A, which is critical to the maintenance of healthy teeth and bones.

A deficiency in any of these 13 vitamins--which is rare in the U.S.--can cause a range of health problems, including depression, anemia and diminished immunity. An average eater who fills his or her plate mostly with fruits, vegetables and whole grains should meet the daily recommended intake of vitamins, says Dr. John W. Erdman Jr., a professor of food science and human nutrition at the University of Illinois at Urbana-Champaign.

Even skipping leafy greens one day or apples and bananas the next won't adversely affect your health--provided this doesn't become a chronic habit. (Children, pregnant or lactating women and the elderly, however, can be more vulnerable to vitamin deficiencies.)

Despite the fact that a balanced diet provides the right amount of vitamins and minerals, millions of Americans consider supplements as an insurance policy against poor eating choices, chronic disease and chance. At least half of all Americans purchase supplements, according to the Council for Responsible Nutrition, a trade association that represents industry suppliers and manufacturers.

Do Vitamins Work at All?
Unfortunately, there isn't a clear-cut answer as to whether vitamins help one's health. Dr. Andrew Shao, the association's vice president of scientific and regulatory affairs, admits that the science of vitamin use can be confusing at times.

"No one study is the final word," he says, referring to Dr. Neuhouser's results. "It's always evolving, and the results in one trial don't erase the evidence." Some research has demonstrated benefits, according to Shao, including a 2003 study that linked multivitamins to reduced heart attack risk and a 1998 study that linked multivitamins to reduced colon-cancer risk.

Still, several academic reviews, including a major National Institutes of Health conference in 2006, have yet to identify convincing evidence for widespread supplement use--except for in a few cases. Vitamin K, which is essential for coagulation, is routinely given to newborn infants to avoid bleeding problems. Pregnant women receive doses of folic acid and other important vitamins for fetal development.

Dr. Neuhouser also suspects that missing bioactives--compounds like anti-oxidants and isoflavonoids that are thought to act synergistically with vitamins and minerals in food--might be the culprit. Researchers are currently trying to understand what role these compounds play in making naturally occurring vitamins powerfully effective.

The bottom line, says Dr. Patsy Brannon, a professor of nutritional sciences at Cornell University, is that consumers should add vitamins and minerals to their diet with fruits, vegetables and whole grains. She doesn't oppose supplement use, but says consumers should avoid self-prescribing and familiarize themselves with when a dose becomes toxic.

Vitamin use, Brannon says, shouldn't exceed 100% of the recommended daily intake, which is determined by the Department of Agriculture.

"It's always an interesting issue," Brannon says of counseling people on whether to take supplements. "You can choose a multivitamin with just 100% of the daily allowance, but you'll be getting those nutrients anyway."

Hospitals cut one source of MRSA

While rates of drug-resistant staph infections appear to be on the rise in society in general, hospitals are making progress at curbing at least one source of infection in some of their sickest patients, U.S. health officials said on Tuesday.

Rates of methicillin-resistant Staphylococcus aureus infections, known as MRSA, caused by tubes used to give drugs and fluids to intensive-care patients fell nearly 50 percent between 1997 and 2007, Dr. Deron Burton of the U.S. Centers for Disease Control and Prevention found.

Drug-resistant bacteria are a growing problem in hospitals worldwide, marked by the rise of superbugs such as MRSA. Many experts believe poor hospital practices are to blame.

Burton and colleagues studied hospital data on blood infections caused by tubes inserted into veins known as central line catheters. They looked at data for both adult and pediatric intensive care units between 1997 and 2007.

They found 1,684 intensive care units reported a total of 33,587 blood infections caused central line catheters during the study period.

Of those, 2,498, or about 7 percent, were drug-resistant strains of MRSA, and 1,590, or 4.7 percent, were staph infections that were susceptible to antibiotics, they reported in the Journal of the American Medical Association.

They said while the overall percentage of infections caused by MRSA increased, the actual number of MRSA cases fell by half during the study period, with steady declines in the infection rate reported from 2001 through 2007.

Burton and colleagues suspect hospitals are following CDC-recommended prevention guidelines, which may have contributed to the improvements.

Dr. Michael Climo of the Hunter Holmes McGuire Veterans Affairs Medical Center in Richmond, Virginia, said in a commentary the report shows that substantial progress is being made in reducing hospital-acquired infections.

"Despite this progress, most ICUs are far from the goal of zero infections and many have not implemented suggested prevention strategies," Climo wrote.

MRSA previously had been a major concern only in hospitals, attacking patients who are already weakened by disease. But recent outbreaks in schools and other public places have raised concerns.

The CDC estimates that 94,000 Americans get serious, invasive MRSA infections each year and nearly 19,000 die.