1. Which botanical products may pose a health risk?
Your concerns are valid: some botanical products produce adverse reactions, even when taken at recommended dose. For example, kava, an herb used to reduce anxiety, recently was removed from the market by several European governments. The Canadian government warned consumers not to consume herbal extracts that contain kava. There have been at least 24 reports of liver toxicity associated with the use of kava products internationally, including one reported death and several cases that required liver transplantation. Other botanical products that are potentially harmful, even at normal dose:
Aloe Vera:A cancer therapy that used injections of acemannan, a mucopolysaccharide derived from aloe vera, caused several deaths. Potential toxicities exist when taken orally. Bitter Melon: Red arils (the covering on the seed) are reportedly toxic in children, causing vomiting, diarrhea, and death. Ingestion of vicine (from the seed) may cause favism characterized by headache, fever, abdominal pain, and coma. Borage: May contain small amounts of the alkaloid amabiline, which is toxic to the liver. Risk of liver damage increases with length of exposure and cumulative dose consumed. Borage oil products should be certified free of unsaturated pyrrolizidine alkaloids (UPAs) down to the level of 0.5-1 ug/g. Chaparral Tea: Severe liver toxicity, requiring liver transplantation in some cases. The FDA issued a health warning urging withdrawal of these products in 1992. Comfrey: Toxic to the liver. Horse Chestnut: Raw horse chestnut seeds are classified by the FDA as unsafe; many of its constituents are considered toxic, such as the glycosides and the saponins. Jin Hu Huan: Can cause hepatitis and dangerously slow heart rate. Kava: May cause liver toxicity. Lobelia: In high doses, causes vomiting, rapid heartbeat, breathing problems, coma, and death. Pau d'arco: Its quinone components are known to have toxic effects. Rhubarb: Chronic consumption can cause kidney and liver damage from its oxalate content. Sassafras: Contains safrole and has caused liver cancer in animal models. It is classified as a carcinogenic (cancer-causing) substance. Risk increases with length of exposure and amount consumed. Toxic reactions include liver cancer and death. Tea Tree Oil: When taken orally, coma and neutrophil leukocytosis (abnormal elevation of white blood cell count) can occur. Yohimbe: Has caused seizures, kidney failure, and death.
The following supplements also may cause toxicity:
Chromium: Cases of liver toxicity and kidney failure have been reported. Germanium: Has caused toxicities of the kidney, liver, myelocytes (a type of white blood cell), and nervous system. To date, nine deaths are reported in the literature from as little as 15 grams cumulative dose. Hydrazine Sulfate: Is known to cause liver and kidney failure; toxicity increases when combined with benzodiazepines, barbiturates, or alcohol.
For further information regarding potential toxicity of botanical agents or supplements, consult the "adverse reactions" section of each monograph.
2. I am concerned that some botanical products may contain contaminants, can you provide names of these products?
Processing flaws and the presence of unstated ingredients, such as potent drugs or hormones, result in product contamination. Because there are no provisions for the FDA to "approve" dietary supplements for safety or effectiveness before they reach the consumer, any botanical or supplement potentially may be contaminated. The following products have been found to contain contaminants:
Blue-green Algae: May contain strains of toxic algae (e.g. microcystin species), which can cause liver toxicity, kidney failure, and neurotoxicity. Burdock/Essiac: Case reports indicate that burdock root contaminated with belladonna alkaloids have caused atropine-like toxicity. Chomper: Herbal laxative that has been contaminated with digitalis (heart medication). Plantain Leaves: Often contaminated with digitalis glycosides. PC-SPES: A recall was issued on February 8, 2002 because of contamination with warfarin. The manufacturers of PC-SPES, Botanic Labs, ceased operations on May 2002. Ginseng (Siberian): Some capsules contain a weed made up of male hormone-like chemicals.
5. Do any botanicals interfere with the metabolism of drugs?
To maintain the proper metabolism of certain drugs by cytochrome p450 (a liver enzyme), patients should discontinue use of the following agents. Increased metabolism of a drug reduces its concentration in the blood and may reduce its effectiveness. Decreased metabolism of a drug increases its concentration in the blood and can lead to toxicity or increased side effects. Essiac: A case of decreased clearance (removal from the blood) of an experimental chemotherapy is reported in a single patient taking Essiac. This may be due to inhibition of cytochrome p450 isoenzymes, hindering their ability to metabolize the chemotherapy agent. Garlic: May induce the cytochrome p450 3A4 isoenzyme, resulting in enhanced metabolism (and decreased effectiveness) of certain drugs. Ginkgo: Preliminary evidence suggests that ginkgo can affect the cytochrome enzymes 1A2, 2D6, and 3A4. However, data are controversial regarding whether ginkgo induces or inhibits individual enzymes. Ginseng (Siberian): Inhibits metabolism of certain medications, leading to higher medication levels in the blood, possibly by inhibition of cytochrome p450 2C19. Goldenseal: May inhibit the 3A4 isoenzyme resulting in increased blood levels of certain medications. Milk Thistle: Inhibits cytochrome P-450 3A4. Although no interactions have been reported, inhibition of drug metabolism may occur for several constituents (e.g. ketoconazole, itraconazole, erythromycin, triazolam). St. John's Wort: Induces cytochrome isoenzyme 3A4, enhancing metabolism of certain medications and reducing their concentration in the blood. Turmeric: In vitro studies indicate inhibition of cytochrome P450 1A1, which may result in increased blood levels of certain medications.
6. I value the benefits of some herbs and other food supplements. Any overall cautions concerning the use of these substances?
In most cases, it is not advisable to use herbs for children or for pregnant or breast-feeding women. All herbs and other supplements should be stopped about one week before surgery because they may interact with anesthesia or interfere with normal clotting. There is a great need for patient education in this matter because improper use, chronic usage or overdose of many botanicals and supplements can result in adverse reactions.
The minimally regulated field of dietary supplements has drawn increasing numbers of people, including patients, to use botanicals, vitamin mixtures and other agents. Health care professionals frequently confront their patients' use of products about which both they and the patient know very little. Our goal is to provide easy access to concise, clinically relevant information about botanicals, vitamins, and related products for health care professionals and consumers. The website also provides monographs on alternative or unproved methods such as oxygen therapy and antineoplastons.
Monographs on each product, authored by an oncology-trained pharmacist who is also a botanicals expert or a cancer nutrition specialist, are based on results of methodologically sound studies, including randomized, controlled, double-blind trials when available. Research is gathered through electronic searches of databases such as Medline, the Cochrane Library and Cancerlit. Information from relevant journal articles, textbooks and reference books is carefully scrutinized, reviewed for quality, and compiled into a complete picture of the herb or supplement. The quality review enables critiques of the most important published studies, which are included with each monograph. Each monograph then undergoes review by at least two other editors or panel advisors before publication.
The website is updated daily as new findings or warnings are released. A site-wide review of each monograph is performed twice a year to ensure that all information is current.
