Answer: The use of herbs as medicine has grown in popularity in this country over the past decade, contributing to a $4.1 billion supplement industry. The popularity of herbs is due to several factors: they can be purchased without a prescription, a belief that "natural" products are safer and the knowledge that many of our modern drugs are derived from herbs. However, there has not been an equal increase in clinical studies. This means that much of the information available to the public is general in nature and not designed for those with specific medical problems. Any supplement use needs to be evaluated in the context of the individual user: their primary diagnosis, any additional conditions and the medications they are taking.

It is important to understand that pharmaceuticals and herbs are not regulated to the same degree. In 1994, the Dietary Supplements Health and Education Act was passed by Congress. Under this act, herbs and a number of other biologically active substances are classified as dietary supplements. Regulation of these supplements is based upon adverse events, i.e., they are considered safe until proven harmful (ephedrine as an example). In contrast, drugs must prove they are safe, e.g. clinical trials, before they are allowed on the market. As a result, herbals can contain pesticides, heavy metals, poisonous plants and even conventional medications without impunity. Remember these products are big business and are not coming from your grandmother's garden.

In addition, even pure products may not be supplying ingredients as advertised. ConsumerLab.com (CL), an independent product testing company, has reviewed a number of health products and the results reflect the lack of standardization in the industry. For instance, in a test of 22 brands of ginseng products, only nine passed CL's criteria: eight contained unacceptable levels of pesticide, two contained unacceptable levels of lead and seven contained less than the required levels of active ingredients. All of the companies listed their products as being "standardized."

Further complicating this issue, active ingredients in herbals have often not been identified or may only be effective in the presence of other active ingredients found in the herb. Variables influencing effectiveness include where a plant was grown, which parts were used, and even which variation is used (e.g., Korean vs. American vs. Siberian ginseng).

Another aspect of supplementation use to consider is drug interaction. People with kidney disease or a kidney transplant are on a number of medications. Herbals can boost or decrease the effectiveness of prescribed pharmaceuticals. Ephedra, often used in weight loss products, causes an increase in heart rate and blood pressure and should not be used in patients with hypertension, congestive heart failure and diabetes. Other examples of negative interactions are: St. John's wort and digoxin, protease inhibitors or cyclosporine; ginseng and anticoagulants or immunosuppressants. It is critical to mention to your physician any herbals, over-the-counter medications and products purchased from health food stores you may be using.

Other herbs that may be problematic are those with diuretic properties. Goldenrod, parsley, uva ursi and juniper berries fall into this category. In fact, juniper and parsley effects are created by irritation of the kidney's epithelial tissue. Other herbals may affect electrolyte balance. Alfalfa and dandelion contain high levels of potassium, of particular concern for those taking potassium-sparing diuretics.

Some herbs have been found to be extremely dangerous. Between 1990 and 1992 the herb Aristolochia, innocently used as a weight loss product, was found to be highly carcinogenic and a direct cause of irreversible kidney failure.

Should someone with chronic kidney disease avoid all herbal products? No, not necessarily. Green tea is an example of a herb that confers benefit with low risk. Research has demonstrated that green tea mildly guards against cardiovascular disease by lowering total cholesterol levels and improving the cholesterol profile (the ratio of LDL cholesterol to HDL cholesterol), reducing platelet aggregation and lowering blood pressure. However, even here caution is advised. Green tea compounds have been reported to enhance vitamin K activity and thus can interfere with warfarin dosing. Furthermore, most of the benefits related to green tea have been from observations, animal or in vitro studies and not rigid clinical trials. Controlled research protocols need to be developed to further study this potentially valuable product. Evidence-based medicine builds upon a foundation of studies that meet scientific criteria. There is no reason why selected herbals felt to have potential benefit, such as green tea, cannot undergo large, multicenter research trials.

You should take with you a recent copy of a chest x-ray and electrocardiogram report, a copy of your most recent laboratory tests, including an HIV test, and the results of a TB skin test. All of your immunizations should be current, including those for hepatitis B and the pneumonia vaccine. Some dialysis units have a policy against using a fax to send information about your HIV status and you may need to send it yourself. You should contact your primary care physician for information about special immunizations that may be required in some countries. Have copies of your current medication list, a complete history and physical examination and your dialysis orders. Although your dialysis unit may send or fax this information, you should carry a copy with you at all times. Wear a medical alert nametag complete with your diagnosis in at least two languages.

When facing the uncertainty of a chronic illness, there is temptation to succumb to a product's promises of alleviation or cure. This is especially true with cancer, but also applies to kidney disease. The web site quackwatch, www.quackwatch.com has informative and valuable articles about dubious medical practices, including herbal supplements. Many herbal products have never been through multicenter, double blind, controlled and randomized trials. Valid data is lacking as to their safety and effectiveness. Anecdotal testimonials are used as substitutes for the valid and rigidly controlled evidence that we have grown accustomed to in the medical practice. Marketing claims that an herbal product has value and is effective can be misleading. The old adage, "If it sounds too good to be true, it probably is" should be kept in mind. In terms of cost/benefit, the costs of an alternative therapy with a marginal benefit reduce resources that could produce more value if used elsewhere in the health market.

Basic healthy living practices will provide the most benefit: for high blood pressure eliminate salt from the diet; for diabetes, be vigilant in monitoring your blood sugars, exercise and eat a balanced diet of fresh foods. These activities also represent areas where you, as the patient, can exercise control over your illness.

In summary, there may be great value to herbal products when used under the proper conditions. However, without controlled clinical trials, data as to their safety and effectiveness is going to be lacking. The public, especially people with any form of kidney disease, should exercise caution when using products of this nature.

Answer provided by Stephen Z. Fadem, MD, FACP, Paul Garney, MS, RD and Bruce T. Smith, MS, RD. Dr. Fadem is a practicing nephrologist in Houston, TX. He has served on numerous committees within the renal community and is a member of several medical societies. Dr. Fadem also serves as a member of the AAKP Medical Advisory Board. Paul Garney, MS, RD and Bruce Smith, MS, RD are dietitians at Davita Med-Center in Houston, TX. Both are active in local renal nutrition projects and participate in a multidisciplinary kidney disease education initiative with Dr. Fadem.

The Dear Doctor column provides readers with an opportunity to submit renal related health questions to healthcare professionals who specialize in the area of concern. The answers are not to be construed as a diagnosis and therefore, altercations in current healthcare should not occur until the patient's physician is consulted.

This article originally appeared in aakpRENALIFE, May 2002 Volume 17 Number 6. 

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