The American Academy of Clinical Toxicology has an Herbs and Dietary Supplements Section. I’ve been reading abstracts from their recent collection of studies:
Here’s a quick and dirty synopsis. The numbers correspond to their abstract number, in case you want to read more:
1. Kava, which has mild sedative qualities and is used as an ant-anxiety herb, probably doesn’t cause liver toxicity as we thought it did.
2. Garcinia cambogia, an herb used for weight loss, caused liver toxicity in a case.
3. Artemisinin, a Chinese herb used to treat malaria, caused liver injury in a case. They said that’s rare.
4. OxyELITE Pro, a dietary supplement used for weight loss and/or muscle building, released a formulation that probably caused liver damage (33 hospitalizations, 3 liver transplants).
5. Tiger King, a Chinese herb for erectile dysfunction, was found to contain the pharmaceutical drug sildenafil (Viagra) and caused liver toxicity in a case.
6. Qibao Meiran Wan, a Chinese herb for “tonifying the liver and kidney, dizziness, premature graying of hair, backache, constipation, and night sweats” caused liver toxicity in a case.
7. Glutamine, an amino acid, caused ammonia buildup and brain injury in a case.
8. Khat, an herb that’s often chewed and leads to mild euphoria, caused liver inflammation in a Somalian man.
9. Pure caffeine sold as a dietary supplement nearly killed a women who took too much.
10. Aconitine, a Chinese herb used as a pain reliever (aka devil’s helmet or monkshood) caused tachycardia in a case.
12. Aconitine caused arrhythmia and kidney herrhorage in a case.
13. Indian rubber vine plant (Crytostegia grandiflora) “led to gastrointestinal, cardiac, electrolyte, and hematological disturbances” in a case.
14. Oleander led to cardiac arrhythmia in a case, three hours after drinking herbal tea prepared from oleander leaves.
15. Star fruit, eaten by people with diabetes to manage blood glucose, caused kidney injury in a woman who had normal kidney function (she drank a large amount of starfruit juice at one sitting), and caused chronic kidney disease in a man who ate star fruit regularly over 2-3 years.
16. If you’re on antiretroviral therapy for HIV/AIDS, you probably shouldn’t take St. John’s wort, black pepper, grapefruit juice, African potato, ginko, ginseng, garlic, goldenseal, kava kava.
17. Traditional Chinese Medicine (TCM) remedies are largely contaminated: 50% contained undeclared plant or animal, 50% contained a pharmaceutical drug, many contained arsenic, lead, and other heavy metals, overall 92% were contaminated!
18. Studying TCM efficacy is difficult.
19. Aristolochia, an herb used for millenia to treat arthritis, edema, wounds, and other ailments contains aristolochic acid which is toxic to the liver.
20. Aristolochia, which is a liver toxin, finds its way into another TCM herbal remedy. Better quality control and testing are needed.
21. More on weeding out Aristocholia from TCM remedies.
22. Pyrrolizidine alkaloids are natural plant insecticides. They are also toxic to human liver. Borage leaf, comfrey, coltsfoot, and some Chinese herbs have high amounts. (They’re also found in food, e.g. milk, eggs, grains, offal, honey.)
23. Pyrrolizidine alkaloids were found in high amounts in chamomile, peppermint, rooibos teas. In lower amounts in black and green teas. Tests conducted in Israel.
24. More on Pyrrolizidine alkaloids. Determining safe thresholds.
25. Resveratrol, which is not an herb itself but an extract from the skin of certain berries, might be protective against liver injury. More study needed.
26. Tripterygium wilfordii, an herb used in TCM for treatment of fever, chills, edema, carbuncles, arthritis, etc., can be toxic to the liver.
27. Herbal weight loss products can cause adverse psychiatric effects.
28. Herbal and ayurvedic remedies were tested for heavy metals. Many contained lead. “Lead toxicity is likely to result from the regular intake.”
29. Herbs, as well as food and fodder plants, have high levels of lead and cadmium in Northern Pakistan. Go up the food chain.
30. Wild cannabis is used as a traditional medicine in South Africa. Treats many skin conditions and produces mild euphoria when smoked. Needs safety study.
31. Green tea extract may have beneficial medicinal properties.
32. Bottle gourd, a plant used in India to treat a number of diseases, contains toxins (curcubitacins) that nearly killed a woman.
33. Many women in Palestine use herbs to treat breast cancer. Side effects, toxicity, efficacy are not fully known.
34. Many pregnant women in developed countries have nausea. About 8% treat it with herbs.
What I learned from all this:
- Herbs probably do have some therapeutic value, at low doses, doses you find in food or teas. When components of herbs are extracted, concentrated, and presented in amounts the body would never otherwise see, they can cause damage, especially to the liver which is the principle site of drug metabolism. For example, turmeric is fine; curcumin, an extract of turmeric, is risky. The caffeine in a cup of coffee or tea is fine; caffeine pills are risky.
- It isn’t just the US that has a problem with contamination. It can be deliberate (cheap filler or pharmaceutical drugs) or unintentional (herbs drawing up lead from soil or absorbing pesticides).
- Many of the purported uses for herbs seem to be from hearsay, at least as I gleaned from this exercise. That doesn’t mean there isn’t real benefit, just that there hasn’t been much study done to document effects. There’s probably a strong placebo effect in traditional herbal medicine, in addition to any clinical effect.
- That starfruit study was something else. It’s apparently known to cause problems with the kidneys, but healthy kidneys? Many people with diabetes don’t even know they have kidney impairment. I think I would stay away from starfruit.