Herbal medicine and dietary supplements are popular ways to enhance health, but it’s essential to understand how they can affect your body — especially when combined with prescription medications.
A recent patient of mine, who was on Zoloft for mood stabilization, started drinking herbal tea containing St. John’s wort. This posed a serious risk because both Zoloft, a selective serotonin reuptake inhibitor (SSRI), and St. John’s wort affect serotonin levels. Taking them together can cause serotonin syndrome, a life-threatening condition that can lead to agitation, fast heartbeat, high blood pressure and more. This illustrates how dangerous mixing supplements with medications can be.
What are dietary supplements?
Dietary supplements are ingested products designed to supplement the diet, coming in various forms such as pills, powders or gummies. Common supplements include vitamins (like vitamin D), minerals (such as calcium), herbs (such as echinacea) and probiotics.
While supplements can help maintain overall health or meet specific nutrient needs, like calcium for strong bones, they shouldn’t replace a varied diet. Some supplements have well-established benefits, but others need more research.
Regulation and safety
The U.S. Food and Drug Administration (FDA) regulates supplements under the Dietary Supplement Health and Education Act of 1994. However, the FDA does not approve supplements for safety or effectiveness before they are sold. It is the responsibility of manufacturers to ensure their products are safe and properly labeled.
Supplements marketed as treating or curing diseases are considered drugs and are subject to stricter regulations. Always follow label instructions and consult a health care provider before taking any supplement. Be cautious of supplements that claim to be "natural" or promise results that seem too good to be true.
Risks of dietary supplements
Dietary supplements can have strong effects and interact with medications. For example:
- Iron supplements and antacids should be taken two hours apart to avoid reduced effectiveness.
- Vitamin B6 may reduce the effectiveness of levodopa, used for Parkinson’s disease.
- Vitamin K can interfere with blood thinners like warfarin.
Always consult a health care provider before starting new supplements, especially if you’re on prescription medications. Certain supplements may cause adverse effects if taken in high doses, for extended periods or when combined with other drugs. If you experience side effects, stop using the supplement and seek medical attention.
Herbal medicines: Natural doesn’t always mean safe
Herbal medicines are made from plants, but just because something is natural doesn’t mean it’s safe. Herbs can affect the body just like conventional medicines and can cause harmful effects if not used properly.
Many herbal medicines are not rigorously regulated. For example, herbal products manufactured outside the U.S. may not be subject to U.S. regulations and could be unlicensed, fake or contaminated. Be especially cautious of herbal products bought online, as they may contain undisclosed pharmaceutical ingredients.
Who should avoid herbal medicines?
Certain groups should avoid herbal medicines or consult a doctor before use:
- People on prescription medications
- Individuals with serious health conditions like liver or kidney disease
- Pregnant or breastfeeding women
- The elderly and children
Always inform your doctor or pharmacist about any herbal medicines you’re taking, especially if you’re undergoing surgery, as some herbs can cause complications.
Tips for safe supplement use
- Consult a health care provider before using any dietary supplement or herbal medicine.
- Follow the instructions on supplement labels carefully.
- Avoid replacing prescription medication or a balanced diet with supplements.
- Be wary of unverified health claims and "natural" labels.
Conclusion
Dietary supplements and herbal medicines can support health, but they need to be used carefully. Always consult with your health care provider before starting a new supplement or herbal product and be mindful of potential interactions with medications. Remember, "natural" doesn’t always mean safe, and being an informed consumer is key to protecting your health.
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Additional resources:
- American Academy of Family Physicians. "Herbal Remedies: Adverse Effects and Drug Interactions." American Family Physician. March 1, 1999. https://www.aafp.org/pubs/afp/issues/1999/0301/p1239.htmll.
- Drug Safety. "Health Risks of Herbal Remedies." 13, no. 2 (August 1995): 81–93. https://doi.org/10.2165/00002018-199513020-00003.
