Vitamins & Supplements: What You Need to Know Before You Dive In
By Health Behavior News Service, Center for Advancing Health
What Are Dietary Supplements and How Are They Regulated?
April
5, 2011 -
Vitamins, herbs and other dietary supplements are sold as natural
alternatives to pharmaceuticals and many people turn to them in an
attempt to improve their health. Others seek supplements to lose weight
or after hearing that they can help with serious medical conditions.
These products are now used at least monthly by more than half of all
Americans—and their production, marketing and sales have become a $23.7
billion industry, according to the Nutrition Business Journal.
98-year-old Bob Stewart, a retired podiatrist and senior Olympian,
credits his use of supplements for his healthy aging. Writer Betsy
McMillan, a mother of two now adult children, however, nearly suffered
permanent liver damage due to a supplement that contained potentially
fatal levels of niacin.
Unlike
pharmaceuticals—which must be FDA-approved as safe and effective before
they can be marketed—supplements are considered as foods by regulators
and assumed to be safe until proven otherwise. Although pharmaceutical
manufacturers face inspections to ensure that the right dose is in the
right pill without dangerous contaminants, supplements do not undergo
such intense government scrutiny.
Despite many reports of health problems, only one supplement has ever
been pulled from the market: the stimulant ephedra, which was banned in
2004 following reports of deaths. With such little regulation and
oversight, safe supplement use requires that consumers be cautious and
savvy.
“Supplement
is a broad term that includes vitamins, minerals, herbs and botanicals,”
says Carol Haggans, a registered dietician and science and health
communication consultant for the Office of Dietary Supplements of the
National Institutes of Health. Herbs and
botanicals are derived from plants, while other supplements may
include animal sources. Vitamins are essential
nutrients made up of organic compounds, while minerals
is an imprecise term for certain chemical elements necessary to life,
like calcium.
“They’re regulated under the umbrella of foods and are not intended to
treat, diagnose, mitigate, cure or prevent disease. If something claims
to do that, then it becomes a drug under FDA regulation,” Haggans says.
She
adds, “The FDA has instituted ‘good manufacturing practices’ (GMP) that
manufacturers must follow to ensure the identity and quality of
supplements and they can take enforcement action if it’s unsafe or unfit
for human consumption, but they do not routinely test products.” Once
manufacturers implement these practices, they can display a seal on
their packaging, noting their compliance.
But
Dr. Bob Linden, a general practitioner and author who has used
supplements but also has seen problems with them in patients, says he’s
rarely seen the GMP seal in stores where he lives in Connecticut,
despite the agency’s plan to complete most of the implementation by last
year.
Looking for Safer Products
So how
can consumers protect themselves and find high-quality products?
Haggans says that several independent organizations test products and
offer their seal of approval only to those that pass. “Those can give
some assurance that the product is properly manufactured, contains the
ingredients listed on the label and doesn't contain harmful levels of
contaminants,” she says. Consumer Reports Health also regularly reviews
supplements but may require a subscription for full access to
information. (See “Finding Safe Supplements” sidebar.)
“I
think people use them primarily because they think they’re natural [and
from] plants,” Linden says. “They also think they’re safe because you
don't need a prescription.” He has taken supplements himself for
arthritis. But he also had one patient who suffered liver damage after
taking a supplement containing Chinese skullcap, which is known to be
dangerous to the liver but is still on the market.
Finding Safe Supplements
Check out these
sources of vitamin/supplement information before plunging in:
“They
can’t label them as treating disease, on the bottle, they say it’s
‘promoting health,’” Linden says. “But people do take them specifically
for [diseases], such as St. John’s wort for depression.”
Managing Interactions and Dosing
Like
drugs, supplements can combine with other medications in unhealthy
ways. “Dietary supplements can interact with both over-the-counter and
prescription medication,” Haggans says. “That’s one reason we tell
people to talk with their doctors about all the supplements that they're
taking.” For example, the anticoagulant medicine warfarin (Coumadin)
can interact with gingko biloba and with garlic and cause bleeding. St.
John’s wort, which is often used to treat depression, can weaken the
effects of birth control pills and other medications. Vitamins C and E
can also potentially interfere with chemotherapy used to treat cancer.
Doctors might not know about interactions between supplements and
prescriptions and since supplement labels don’t list warnings, patients
need to do their own research: look for guidance from the sites listed
in the resource section and talk to a nutritionist or check with
reliable sources at “health food” stores or reputable “wellness”
centers. This is a situation where watching carefully for
side effects is especially important and consumers are mostly on
their own to be vigilant.
Some
supplements can be monitored by testing blood levels. This can be
expensive but it might also reduce problems related to potential
toxicity or unusual individual reactions. Check with your doctor to see
if blood tests might be suitable for you.
Researching Appropriate Supplements
The
scientific evidence supporting the use of supplements is often weaker
than that available for drugs because of the lack of legal requirements
to prove safety and efficacy. “You can get a lot of conflicting
evidence depending on where you look,” Haggans says.
The
Office of Dietary Supplements, the National Center for Complementary and
Alternative Medicine, and the Memorial Sloan-Kettering Cancer Center all
keep regularly updated fact sheets on the most commonly used herbs,
supplements and vitamins. (See sidebar.)
Beyond
that, there are several important principles to keep in mind if you take
supplements. First, “Natural is not always safe,” Haggans says. Both
arsenic and poisonous mushrooms are completely natural but deadly to
eat. Second, never rely on a single study or personal story to provide
definitive evidence.
In
contrast, review articles—particularly those done under the rigorous
standards of the Cochrane
Collaboration—can be a high quality source of evidence. “Review
articles like Cochrane Reviews look at the totality of the evidence in
different populations,” Haggans says, which is especially important
since studies of nutrition often have conflicting results.
For
example, beta-carotene was once thought to be a universal cancer
fighter—but long-term studies found that smokers and other people at
high risk for lung cancer who took it actually increased their risk of
contracting the disease and their risk of early death from other causes.
Avoiding Overdose
Dose
is also a critical consideration. “Many nutrients have an upper limit,”
Haggans says. “More is not better and above certain amounts, they can be
toxic.” She notes that iron is one mineral that is dangerous in high
doses. Niacin—as McMillan unfortunately found out—is another.
The
use of supplements—like much of American life—is highly susceptible to
fashion. The “in” supplements of the 1980s and 90s like gingko biloba
and ginseng were followed by an antioxidant fad for vitamins A, C and E
in the 2000s.
The 1994 study on beta-carotene and smoking and a 2005
finding that high-dose vitamin E may do harm took some steam out of
those trends. Currently, omega-3 fatty acids and vitamin D are the
headline makers. Overall, the supplement industry has grown
dramatically, continuing to increase sales despite the recession.
Given
this—and given the fact that some risky supplements like the Chinese
skullcap that harmed Dr. Linden's patient remain on the market—it’s
important that people considering them “do their homework,” as Haggans
puts it. “Go to a trusted source like your doctor for information.” At
the least, your doctor can help you weigh the evidence.
Narrowing Your Choices
Linden
suggests closely following directions on products’ bottles. He adds,
“Stay away from supplements [advertised for] weight loss—you don’t know
what you're getting and it’s looking for trouble.” Some weight-loss
supplements and some sold as sexual aids have been found to contain
prescription medications that were illegally manufactured.
Stewart’s advice is to stick to supplements that are essentially
unaltered whole foods, like flaxseed and vinegar. “The type of food we
have now in grocery stores is terrible,” he says, echoing the complaints
of nutrition experts about over-processed and chemical-laden foods.
Supplements can be helpful in some cases but they are less well
regulated than drugs and have many of the same side effects, drug
interactions and toxicities at high doses seen with pharmaceuticals.
Consequently, they should be used with care and with guidance from a
doctor.
Published by Health Behavior News Service Lisa Esposito, Editor Written by Maia Szalavitz,
Contributing Writer Designed by Brandon Moore,
Dir. of New Media
The Health Behavior News
Service of The Center for Advancing Health does not provide medical
advice or consultation. The Prepared Patient is a new series
intended to help people make informed choices about their health
care.
Keep up with the latest news for senior citizens, baby
boomers
April
5, 2011 -
Vitamins, herbs and other dietary supplements are sold as natural
alternatives to pharmaceuticals and many people turn to them in an
attempt to improve their health. Others seek supplements to lose weight
or after hearing that they can help with serious medical conditions.
These products are now used at least monthly by more than half of all
Americans—and their production, marketing and sales have become a $23.7
billion industry, according to the Nutrition Business Journal.
The
use of supplements—like much of American life—is highly susceptible to
fashion. The “in” supplements of the 1980s and 90s like gingko biloba
and ginseng were followed by an antioxidant fad for vitamins A, C and E
in the 2000s.