Herbal Supplements for the Kidney Patient: Caveat Emptor

By Beverly A. Cohen, MHS, RD, LD

Herbal Supplements for the Kidney Patient
As a kidney patient, you may be aware of the need to consult your physician before taking any over-the-counter (OTC) drugs. After all, what may be safe for most people may not be safe for you. When it comes to herbs, they should be thought of as diluted drugs and should not be taken before consulting your physician. If you are someone with kidney disease who may be contemplating purchasing OTC herbal medications, it would serve you well to consider the old phrase, caveat emptor, or “Let the buyer beware.


What are Herbs?
In a medicinal (and unregulated) sense, herbs have long been defined as crude drugs of vegetable origin used to diagnose, treat, cure, or prevent disease. Examples of herbs used for medicinal purposes include:

  • chamomile
  • echinacea
  • gingko biloba
  • ginseng
  • golden seal root
  • sassafras

In a culinary sense, herbs are defined as vegetable products used to add flavor or aroma to food. Small amounts of herbs–such as thyme, nutmeg, basil, and rosemary–are fine to use in cooking. In fact, they are a good way to enhance flavor in salt-free recipes.

Government Regulation
The overwhelming difference between herbal supplements and all OTC and prescription drugs is the fact that herbal supplements are not regulated by the U.S. government, while OTC and prescription drugs are regulated. This is because herbs are marketed as food supplements, which are not subject to the strict standards required by prescription drugs.

No regulation means no testing for safety and efficacy. In other words, the questions “Is it safe?” and “Does it work?” are not required to be answered. Caveat emptor!

No Legal Standards and the “Experts”
There are no “legal standards of identity” established for herbal supplements. This means that quality control is non-existent, and the risk of contamination or substitution is ever-present. With regard to issues of purity, the buyer is dependent solely on the reputation of the manufacturer.

To thoroughly understand herbal drugs, you need to know the herb’s botany, chemistry, and pharmacology. This is information that very few herbalists (people who use herbs) have and is why they must rely on anecdotal information or the opinions of “experts.” In fact, these “experts” tend to freely offer advice about the treatment of serious illnesses with herbal supplements without mentioning the potential side effects.

No two herbs are exactly alike, even if they are labeled on the package as the same plant. The popular names of plants are numerous and not exact. For example, the name “Mistletoe Tea” on an herbal tea label could refer to as many as 200 different species of this plant. And there is no way of knowing whether the herb is safe, uncontaminated, and in a chemical form that your body can use.

A Potentially Dangerous Mix for Kidney Patients
Herbal supplement use in kidney patients is potentially dangerous for many reasons. Herbs contain potent active ingredients that, if used regularly even in small doses, can accumulate in your body and cause problems. For example, some herbal supplements (such as gingko biloba and ephedrine) may have ingredients that could affect blood pressure control. Or they may have ingredients (such as licorice) that affect fluid and sodium retention and potassium excretion. Many of these supplements (such as senna, aloe, and rhubarb) also have laxative properties or act as a diuretic (as do juniper berries and buchu leaves).

Echinacea, a popular herb that many people use to prevent or treat the common cold, has properties that stimulate the immune system. Therefore, it should not be used by people with autoimmune disease (such as type 1 diabetes, rheumatoid arthritis, or lupus) or by people with transplants, who are on immunosuppressant medications.

There are even herbs that are directly toxic to the kidneys. These include chaparral, periwinkle, and sassafras.

The Message is Clear
Finally, as with all prescription drugs, herbal supplements can interfere with the action of other medications or even with another herbal supplement if taken simultaneously. It has been estimated that, on average, dialysis patients take as many as 10 different medications daily. Therefore, kidney patients have a great potential for this type of problem.

It is very important that you review the potential problems of herbal supplements with your nephrologist or renal dietitian and never change your nutrition or treatment regimen without checking with your doctor and dietitian first!

Do not take an herbal supplement if there is already a drug available that is quality-controlled and has been tested. However, if you, along with your medical team, do decide to try an herbal supplement, consider these suggestions:

  • Only buy from reliable sources. Make sure the label has a list of ingredients, precautions, address of the manufacturer, and the expiration date.
  • Use special caution with herbs purchased in foreign countries and through mail or Internet orders. Be especially careful with Oriental herbs.
  • Start with low doses. Do not take more than the recommended amount.
  • Take only one herb at a time. Do not combine herbs.
  • Monitor interactions, if any, between prescription drugs and herbal supplements. Stop taking herbs if there is any type of problem or side effect and contact your physician.
  • Remember that self-medication involves potential risk. Never substitute herbal supplements for traditional medical therapy when treating what may be a serious illness such as kidney disease.
  • “Natural” does not mean harmless!


Be wary of anyone who steers you away from standard medical treatment. If a promise sounds too good to be true, it probably is too good to be true!

Be Careful! Be Smart! Ask First!

About the Author
Beverly H. Cohen, MHS, RD, LD, is a renal dietitian for DaVita Corporation in Rockville, MD. In addition to her nutrition degree, she has a Master’s degree in Maternal and Child Health and has been working happily with kidney patients for 16 years.


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