Red Clover

Red clover has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating	Health Concerns
	Cough Eczema Menopause
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies): Traditional Chinese Medicine and Western folk medicine used this plant as a diuretic, a cough expectorant (an agent that promotes discharge of mucus from the respiratory passages), and an alterative.¹ Alterative plants were considered beneficial for chronic conditions, particularly those afflicting the skin.

Active constituents: Red clover is known as an alterative agent (i.e., one that produces gradual beneficial changes in the body, usually by improving nutrition; also known as a “blood cleanser”). It is a traditional remedy for psoriasis and eczema. However, the mechanism of action and constituents responsible for red clover’s purported benefit in skin conditions are unknown. Modern research has revealed that red clover also contains high amounts of isoflavones, such as genistein, which have weak estrogen-like properties.² Modern research has focused on a red clover extract high in isoflavones as a possible treatment for symptoms associated with menopause and cardiovascular health in menopausal women. A double-blind trial found that red clover improved cardiovascular function in menopausal women,³ but it has not been shown to provide any benefits for symptoms of menopause (such as hot flashes or vaginal irritation). Various laboratory studies and one case report of a man with prostate cancer suggest red clover isoflavones may help prevent cancer.⁴ ⁵ In another case study, use of red clover by a man with prostate cancer led to noticeable anticancer effects in his prostate after the cancer was surgically removed. Although the isoflavones in red clover may help prevent certain forms of cancer (e.g., breast and prostate), further studies are needed before red clover is recommended for cancer patients.

How much is usually taken? Traditionally, red clover is taken as a tea, by adding 1 cup (250 ml) of boiling water to 2–3 teaspoons (10–15 grams) of dried flowers and steeping, covered, for ten to fifteen minutes.⁶ Three cups (750 ml) can be drunk each day. Red clover can also be used in capsule or tablet form, equivalent to 2–4 grams of the dried flowers. Also, 1/2–3/4 teaspoon (2–4 ml) of tincture three times per day may be taken. Standardized extracts providing 40 mg isoflavones per day are available as well.⁷

Are there any side effects or interactions? Non-fermented red clover is relatively safe. However, fermented red clover may cause bleeding and should be avoided. Red clover supplements should be avoided by pregnant or breast-feeding women and their safety has not been established in young children and infants.

Are there any drug interactions? Certain medications may interact with red clover. Refer to the drug interactions safety check for a list of those medications.

References:

1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 177–8.

2. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 177–8.

3. Nestel PJ, Pomeroy S, Kay S, et al. Isoflavones from red clover improve systemic arterial compliance but not plasma lipids in menopausal women. J Clin Endocrinol Metab 1999;84:895–8.

4. Yanagihara K, Toge T, Numoto M, et al. Antiproliferative effects of isoflavones on human cancer cell lines established from the gastrointestinal tract. Cancer Res 1993;53:5815–21.

5. Stephens FO. Phytoestrogens and prostate cancer. Possible preventive role. Med J Australia 1997;167:138–40.

6. Foster S. Herbs for Your Health. Loveland, CO: Interweave Press, 1996, 76–7.

7. Nestel PJ, Pomeroy S, Kay S, et al. Isoflavones from red clover improve systemic arterial compliance but not plasma lipids in menopausal women. J Clin Endocrinol Metab 1999;84:895–8.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2003.