Herbal supplements are a multibillion-dollar-a-year industry used by more than 38% of Americans. If you're one of them, how can you find out if your supplement works, or if it's safe?
Under the Dietary Supplement Health and Education Act of 1994, the FDA treats supplements as food. Unlike prescription and over-the-counter drugs, herbal medicines and supplements can be sold without proof of their dosage, purity, composition, effectiveness, or even safety. And they can remain on the market until the FDA proves them unsafe after reviewing complaints filed by doctors and consumers. This can — and does — take years.
Although years after the supplement act became law, the FDA said it planned to adopt new policies on monitoring product and ingredient safety, it has not yet done so.
Researchers with the National Institutes of Health have conducted dozens of studies on supplements from acai berry to magnesium to zinc to look at whether they really work.
Most supplements show mixed results. For example, some studies show ginger may be effective for pregnancy-related nausea and vomiting, but has not proven effective for other types of nausea. Saw palmetto may be effective for enlarged prostates, and St. John's wort for mild depression.
Other supplements also show mixed results. Case in point: echinacea, the best-selling herb claiming to ward off colds. A blinded, placebo-controlled 2010 study in the Annals of Internal Medicine reported that echinacea was of no value in preventing or treating colds. Studies of garlic, taken to lower cholesterol, have also had varied outcomes.
One reason for the variability is lack of standardization. A study may use different parts of an herb, or even different species, and that may affect outcomes. The supplements you can buy may not offer the same herb or nutrient used in the study. The concentration or dose of an herb in a supplement can vary, too, and a product may not even provide enough to make a difference.
While the FDA works to tighten the rules and gather evidence, consumers need to heed this advice:
Do your homework to see if a supplement is right for you based on your health status. Tell your doctor about all supplements you take. Talk with your doctor first if you're pregnant or nursing, take other medications, or have an illness such as heart disease, diabetes, or cancer.
Don't fall for drivel and hype. Supplements can't claim to treat or cure with no proof. But they can use confusing "structure/function" claims like "supports the immune system" without a shred of evidence. Ask if there is research to show if it works. Don't be fooled by a supplement touting a "breakthrough" or "instant results.
Just because a supplement is labeled "natural" doesn't mean it's safe or effective.
Look for a quality control seal. Supplements marked USP Verified, NSFC, or Consumer Labs (CL), NFL/NFLPA guarantee that the contents match the label.
Keep in mind that, according to the National Center for Complementary and Alternative Medicine, the active ingredients in many supplements aren't known. The contents of a supplement may differ from what's on the label, so you may be taking less or more of the supplement than what the label says.
Supplements rarely come with package inserts, or instructions like FDA-approved prescription and over-the-counter medications do, so there is usually not a list of side effects, contraindications, and interactions. Here are a few to ponder:
St. John's wort may worsen sunburns and can effect how the liver breaks down other medicines. It can hinder birth control pills, heart drugs, other prescription antidepressants, and a host of other medications. It also may interfere with medications used if you have a transplanted organ.
Echinacea could be risky if you're allergy-prone or have an autoimmune disease such as lupus.
Ginger, gingko, garlic, fish oil, and coenzyme Q10 thin the blood and could reduce clotting in surgery, especially if you also take vitamin E, aspirin, or other blood thinners.
Vitamin E, in excess, may actually increase cardiovascular risk, heart failure, and hospital admission for heart disease, in people with existing cardiovascular disease.