Is your herbal supplement safe and effective?
AN APPLE A DAY - Tyrone M. Reyes M.D. (The Philippine Star) - April 6, 2015 - 10:00am

Many Filipinos use botanical or herbal preparations with the expectation that the products will protect or improve their health.  However, not only are the purported benefits of herbal supplements dubious  several well-designed, controlled trials have found that some popular botanicals are ineffective at treating the problems that manufacturers claim they help  the supplements can also be harmful.

Many people assume that dietary supplements are inherently safe because they’re sold without prescription.  This is particularly the case for herbal products, which some people perceive as “natural” and therefore safer than artificial “chemicals.”  But some supplements contain biologically active compounds that can cause serious adverse effects on their own or when herbs and prescription or over-the-counter drugs are used together, which can trigger interactions that may enhance, reduce or eliminate the effects of a drug in ways that are largely unknown.

Herbal supplements are not drugs

Herbal supplements, intended to maintain health but not treat disease, aren’t considered to be drugs by the Food and Drug Administration (FDA).  As a result, botanicals are only loosely regulated and not subject to the same rigorous testing as traditional medications. That leaves the effectiveness, quality, and safety of herbal supplements questionable.  With that in mind, here are some facts that you should consider if you’re currently taking, or considering taking, an herbal supplement.

Very few well-designed clinical trials have been performed on herbal supplements.  In most cases, not enough scientific evidence exists to draw conclusions about the safety and effectiveness of herbal products.

Knowledge of adverse effects comes predominantly from case reports and small, nonrigorous clinical trials, instead of larger, more reliable systematic studies.

Herbal supplements typically contain multiple ingredients difficult to isolate and produce in standardized amounts. (Conventional drugs are synthesized in labs using standardized methods to ensure batch-to-batch consistency and quality control).  Consequently, the active ingredients in herbal products prepared by different — or even the same — manufacturers can vary substantially.

Dose recommendations vary widely among brands because so little data are available about effective dosages.

Potency varies among the many forms of herbal products, such as tablets and capsules, liquid and solid extracts, powders, fresh or dried products, tea bags, tinctures, lotions and gels.  Dosage strengths vary depending on the part of the plant from which the ingredients are obtained:  petals, seeds, stems, roots, and leaves.

Related but not identical species of the same plant may be used in products marketed as the same.  For instance, at least three species of echinacea are used in herbal products, resulting in different chemical makeup among products.

Labels may be inaccurate.  Discrepancies are common between the ingredients listed on the label and what the product actually contains.

A supplement’s effectiveness can be influenced by the botanical’s harvesting and storage conditions, such as the climate it was raised in and the length of time it was stored.

Botanical manufacturers are responsible for monitoring their own product’s potency and purity.  They must guarantee their products contain the proper ingredients in the proper doses; aren’t contaminated with potentially harmful substances such as metals, allergens, and pesticides; and are adequately packaged and labeled.  However, few FDA safeguards are in place to ensure these rules are followed.

Herbal effects

Herbs are biologically active agents that can have powerful and sometimes unforeseen effects on the body.  Herbal supplements can affect:

Bleeding and coagulation:  Many herbs interfere with blood clotting — a dangerous effect if you’re taking an anticoagulant, have a bleeding disorder or are scheduled for surgery.

Blood sugar:  Herbs can lower or raise your blood sugar, even if you don’t have diabetes.

Liver enzymes:  Herbs can affect the production of liver enzymes, interfering with the liver’s ability to process medications.  Subsequent interactions or adverse effects can range from ineffectiveness to toxicity.

Blood pressure:  A number of herbal supplements can make your blood pressure dangerously high or low.

Hormones:  Some herbal supplements have hormone-like actions and affect hormone levels.  Hormone-sensitive conditions like breast, uterine or ovarian cancers can be made worse by exposure to supplements that act like estrogen or other hormones.

Common herbal supplements

Listed below is a brief summary of the 10 most common herbal and botanical dietary products and supplements available on the market.  The discussion will proceed in the following sequence: ? Intended uses; ? What the science says; * Special precautions; ? Common side effects; and (-) Possible interactions.

1. Acai berry.  ? To lose weight; slow aging.  ? No reliable scientific evidence supports the use of acai supplements for any reason.  * Safety and ideal dosage not established.  Don’t use before getting an MRI — it could affect results.  ? None reported for supplements but drinking raw acai juice has been linked to Chaga’s disease outbreaks from parasites.  (-) None established but testing has been limited.

2. Echinacea. ? To prevent or reduce the duration and severity of colds.  ? Inconsistent findings; not clear what effect it has on colds and immunity, if any.  * Don’t use if you’re allergic to ragweed and other plants in the daisy family.  Could worsen some autoimmune disorders.  ? Stomach upset, headache, rash. (-) Caffeine, immunosuppressants, antidepressants, heart drugs, antibiotics, muscle relaxants, some drugs for asthma, migraine, Alzheimer’s, and lung disease.

 3. Garlic. ? To lower cholesterol and blood pressure; fight cancer, infections, diabetes, arthritis, and Alzheimer’s.  ?  Though lab and animal studies have shown benefits, no human studies have shown supplements to be effective or beneficial.  * Supplement form may reduce blood clotting.  ? Stomach upset, heartburn, bad breath, and body odor.  (-) Blood thinner, antihypertensives, statins, drugs for diabetes, cancer, and HIV.

 4. Ginger. ? To relieve nausea; treat muscle and joint pain and arthritis.  ? Mixed findings. May help reduce nausea and vomiting after surgery.  No evidence to support its use for other purposes.   * Don’t use if you have a heart condition or bleeding disorders.  Can lower glucose levels.  ? Stomach upset and heartburn.  (-) Aspirin, ibuprofen, naproxen, blood thinners, calcium channel blockers, insulin and other diabetes drugs.

 5. Ginkgo biloba. ? To sharpen memory and concentration, improve blood flow, and circulatory disorders.  ? Inconsistent findings that lean towards no benefit.  * Never ingest raw or as roasted ginkgo seeds. ? Headache, stomach upset, palpitations, dizziness, rash and bleeding.  (-) Aspirin, blood thinners, antidepressants, antihypertensives, insulin and other diabetes drugs.

 6. Ginseng (Asian ginseng).  ? To increase energy; boost the immune system; treat diabetes; relieve menopausal symptoms.  ? Unclear or inconclusive findings. Some small studies say it may help control blood sugar.  * Use with caution if you have high blood pressure.  Can lower glucose levels.  ? Anxiety, loss of appetite, and insomnia.  (-) Blood thinners, antihypertensives, insulin, and other diabetes drugs.

 7. Kava.  ? As a sleep aid; to treat menopausal symptoms.  ? Studies have linked it to a risk of severe liver damage, and all research on it has been suspended.  * Do not use:  May cause liver damage, including hepatitis and liver failure. ?Liver damage; dystonia (muscle spasms, involuntary movements); scaly, yellowed skin; and drowsiness. (-)  Alcohol, sedatives, antidepressants, and many more.  

 8. Saw palmetto. ? To reduce symptoms of benign prostatic hyperplasia (BPH); and promote general prostate health.  ? Not enough scientific evidence supports its use for any reason.  *  Use with caution if you have a bleeding disorder.  ? Stomach upset and dizziness.  (-) BPH drugs, aspirin, ibuprofen, naproxen, and blood thinners.

9. St. John’s wort.  ? To relieve depression, anxiety, sleep disorders, irritable bowel syndrome and hot flushes.  ?  Inconsistent findings, though most studies suggest it works better than a placebo to treat mild to moderate depression.  * Long-term safety and effectiveness not established.  Never use when taking warfarin. ? Stomach upset, headache, fatigue, dry mouth, and sun sensitivity.  (-) Blood thinners, digoxin, anticonvulsants, immunosuppressants, antidepressants, antipsychotics, antivirals, and some cancer drugs.

10. Yohimbe.  ? To treat erectile dysfunction; enhance sexual desire; and weight loss.  ? No reliable scientific evidence supports its use for any reason.  * Do not use:  Dangerous when taken long term or in large doses. Don’t use if you have kidney problems or a psychiatric condition.  ? High blood pressure, increased heart rate, headache, anxiety, dizziness, stomach upset, tremors and sleeplessness. (-) Antidepressants, antipsychotics, antihypertensives, and stimulants.

What you should do

Take these steps to limit the possibility of problems when using herbal products:

Make sure your doctors know what herbs you use.

Avoid herbs if you’re on drug therapy to control a chronic medical condition; or if you are undergoing cancer treatment.

Don’t combine herbs with over-the-counter drugs that have similar effects.

Don’t substitute an herb for a prescription drug recommended by your doctor.

Always use a relatively low dose when taking herbal preparations.

Limit the amount of herbal products you use.

Stop taking herbal supplements at least two weeks before surgery; many interact with anesthesia or increase bleeding.

Stay alert for new, unexplained symptoms and promptly report any to your doctor.

* * *    

For further information, you may access the Institute for Safe Medication Practices at www.consumermedsafety.org and the American Geriatrics Society website at www.americangeriatrics.org.

 

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