In 2003, Mary Palmer, MD, an emergency room physician and toxicologist, along with her colleagues, published an article in Lancet which analyzed nearly 500 calls about bad reactions to supplements that had been phoned to 11 poison control centers in the US in 1998.
"When I started the study, I thought that maybe the safety problems with supplements really were mild and that my worries were unfounded," says Palmer. "I was very surprised to see how serious the adverse reactions really were." A third of them included heart attacks, liver failure, bleeding, seizures, and death.
In the US, prescription medications cause an estimated 100,000 deaths and 2.2 million adverse reactions each year. While the toll from supplements is nowhere near as great, it’s far from trivial. For example, more than 20,000 complaints about weight-loss products containing ephedra, including scores of deaths, have been registered during the past decade.
In the US, supplements are regulated so much more loosely than drugs that it’s impossible to know how much harm they cause. Drugs can be sold only if companies have enough evidence to convince the FDA and panels of independent experts that they’re safe and effective and that their benefits justify their risks. In contrast, "The dietary supplement market is the Wild West," says Henry Waxman, a California congressman and longtime champion of measures to protect consumers’ health.
So, how safe are herbal supplements? Here’s what you need to know about the 10 most popular ones. Just keep in mind that most reactions are rare; in some cases, they’re based on just one or two reports from physicians. Until more research is done, it’s probably wise for children and pregnant or nursing women not to take any of these supplements.
The 10 supplements will be discussed as to: a) what consumers expect (indication), b) reported reactions (side effects), c) who should be especially careful (precautions), and d) drugs it interacts with (drug interaction).
1) Black Cohosh
a) To relieve symptoms of menopause.
b) Mild gastrointestinal distress.
c) Women who have had breast cancer (in an animal study, black cohosh caused cancer to spread).
d) No drug reactions known.
2) Cranberry
a) To prevent or treat urinary tract infections.
b) Regular use of cranberry concentrate tablets might increase the risk of kidney stones.
c) People susceptible to kidney stones.
d) Antidepressants and prescription painkillers.
3) Echinacea
a) To prevent or treat colds or other infections.
b) Minor gastrointestinal symptoms. Increased urination. Allergic reactions.
c) People with autoimmune diseases (like multiple sclerosis, lupus, and rheumatoid arthritis). May also trigger episodes of erythema nodosum, and inflammation that produces nodules under the skin.
d) No drug interactions known.
4) Garlic
a) To lower cholesterol levels.
b) Unpleasant breath odor. Heartburn and flatulence.
c) People who are about to have – or have just had – surgery (garlic thins the blood). Women just before or after labor or delivery.
d) Blood-thinning drugs like Coumadin (warfarin), heparin, or aspirin. Blood-thinning supplements like ginkgo or high doses of vitamin E. Chloroxazone, which is used to treat painful muscle conditions. HIV drugs.
5) Ginkgo Biloba
a) To improve memory.
b) Mild headache. Upset stomach. Seizures (possibly caused by contamination with ginkgo seeds, which are toxic).
c) People with bleeding disorders like hemophilia. People who are about to have – or have just had – surgery. Women just before or after labor or delivery. People with diabetes.
d) Blood-thinning drugs like Coumadin (warfarin), heparin, or aspirin. Blood-thinning supplements and high doses of vitamin E. The antidepressant trozodone. Antidiabetic drugs. Thiazide diuretics.
6) Ginseng
a) To increase energy and relieve stress.
b) Insomnia. Menstrual abnormalities and breast tenderness with long-term use.
c) Women who have had breast cancer (ginseng stimulated the growth of breast cancer cells in test tubes). People with high blood pressure who aren’t taking medication to lower it.
d) Any drug metabolized by the enzyme CYP 3A4 (ask your physician). MAO inhibitor drugs or digitalis. May increase the activity of insulin and oral hypoglycemics and decrease the activity of Coumadin (warfarin) and ticlopidine.
7) Saw Palmetto
a) To prevent or relieve the symptoms of an enlarged prostate.
b) Mild gastrointestinal distress.
c) People with bleeding disorders like hemophilia. People who are about to have – or have just had – surgery.
d) Blood-thinning drugs like Coumadin (warfarin), heparin, or aspirin. Blood-thinning supplements like ginkgo or high doses of vitamin E.
8) Soy Isoflavones
a) To relieve menopausal symptoms, prevent breast or prostate cancer, and strengthen bones.
b) None reported.
c) Women who have had – or are at high risk for – breast cancer (soy isoflavones may increase cell proliferation). Pregnant women. People with impaired thyroid function.
d) No drug interaction known.
9) St. John’s Wort
a) To alleviate depression.
b) Mild gastrointestinal distress. Rash. Tiredness. Restlessness.
c) People with skin that’s sensitive to sunlight. People taking UV treatment. People with bipolar disorder.
d) Ritalin, ephedrine (found in ephedra), and caffeine. May increase the activity of protease inhibitors (for HIV), digitalis (for heart disease), statin drugs (for high cholesterol), warfarin (blood thinner), chemotherapy drugs, oral contraceptives, tricyclic antidepressants, olanzapine and clozapine (for schizophrenia), and theophylline (for asthma). May increase sensitivity to sunlight if combined with sulfa drugs, Feldene (anti-inflammatory), or Prilosec or Prevacid (for acid reflux).
10) Valerian
a) To induce sleep or relaxation.
b) May impair attention for a few hours.
c) People about to operate heavy machinery or drive.
d) May increase the activity of central-nervous-system depressants like barbiturates (such as Seconal) and benzodiazepines (such as Valium or Halcion).