Red clover is a wild plant that is used for grazing cattle and other animals. It has also been used medicinally to treat a number of conditions. Traditionally, these have included cancer, whooping cough, respiratory problems, and skin inflammations, such as psoriasis and eczema. Red clover was thought to “purify” the blood by acting as a diuretic (helping the body get rid of excess fluid) and expectorant (helping clear lungs of mucous), improving circulation, and helping cleanse the liver.
Modern scientific tests have shown that red clover contains isoflavones, plant-based chemicals that produce estrogen-like effects in the body. Isoflavones have shown potential in the treatment of a number of conditions associated with menopause, such as hot flashes, cardiovascular health, and osteoporosis. However, as researchers have become aware of the side effects of taking estrogen, there is also some concern about the safety of isoflavones. And the evidence that red clover helps reduce any menopausal symptoms — like hot flashes — is mixed.
Red clover is a perennial herb that commonly grows wild in meadows throughout Europe and Asia, and has now been naturalized to grow in North America. The red flowers at the end of the branched stems are usually dried for therapeutic use.
Medicinal Uses and Indications:
Red clover is a source of many nutrients including calcium, chromium, magnesium, niacin, phosphorus, potassium, thiamine, and vitamin C. Red clover is a rich sources of isoflavones (chemicals that act like estrogens and are found in many plants).
Researchers theorize that red clover might help protect against heart disease, but studies in humans have not found strong evidence. Red clover isoflavones have been associated with an increase in “good” HDL cholesterol in pre- and postmenopausal women, but other studies show conflicting evidence. One study found that menopausal women taking red clover supplements had more flexible and stronger arteries (called arterial compliance), which can help prevent heart disease. Red clover may also have blood-thinning properties, which keeps blood clots from forming. It appears to improve blood flow.
Researchers also think that isoflavones, like those found in red clover, might help reduce symptoms of menopause because of their estrogen-like effects. But so far studies have not been conclusive. Several studies of a proprietary extract of red clover isoflavones suggest that it may significantly reduce hot flashes in menopausal women. The largest study, however, showed no such effect.
As estrogen levels drop during menopause, a woman’s risk for developing osteoporosis (significant bone loss) goes up. A few studies suggest that a proprietary extract of red clover isoflavones may slow bone loss and even boost bone mineral density in pre- and perimenopausal women. But the evidence is preliminary, and more research is needed to say for sure.
Based on its traditional use for cancer, researchers have begun to study isoflavones from red clover. There is some preliminary evidence that they may stop cancer cells from growing or kill cancer cells in test tubes. It’s been proposed that red clover may help prevent some forms of cancer, such as prostate and endometrial cancer. But because of the herb’s estrogen-like effects, it might also contribute to the growth of some cancers, just as estrogen does. Until further research is done, red clover cannot be recommended to prevent cancer. Women with a history of breast cancer should not take red clover.
Traditionally, red clover ointments have been applied to the skin to treat psoriasis, eczema, and other rashes. Red clover also has a history of use as a cough remedy for children.
Dosage and Administration:
Red clover is available in a variety of preparations, including teas, tinctures, tablets, capsules, liquid extract, and extracts standardized to specific isoflavone contents. It can also be prepared as an ointment for topical (skin) application.
Red clover has been used traditionally as a short-term cough remedy for children. Products containing isolated red clover isoflavones are very different than the whole herb, however, and are not recommended for children. Do not give a child red clover without talking to your pediatrician first.
Dose may vary from person to person, but general guidelines are as follows:
- Dried herb (used for tea): 1 – 2 tsp dried flowers or flowering tops steeped in 8 oz. hot water for 1/2 hour; drink 2 – 3 cups daily
- Powdered herb (available in capsules): 40 – 160 mg per day, or 28 – 85 mg of red clover isoflavones
- Tincture (1:5, 30% alcohol): 60 – 100 drops (3 – 5 mL) three times per day; may add to hot water as a tea
- Fluid Extract (1:1): 1 mL three times per day; may add to hot water as a tea
- Standardized red clover isoflavone extracts: directions on product labels should be carefully followed
- Topical treatment (such as for psoriasis or eczema): an infusion, liquid extract, or ointment containing 10 – 15% flowerheads; apply as needed unless irritation develops. Do not apply to an open wound without a doctor’s supervision.
Although some red clover isoflavones are being studied for a variety of conditions, it is important to remember that extracts of red clover isoflavones are very different from the whole herb. In fact, they represent only a small, highly concentrated part of the entire herb.
No serious side effects from red clover have been reported in people taking red clover for up to one year. General side effects can include headache, nausea, and rash. However, animals that graze on large amounts of red clover have become infertile.
Interactions and Depletions:
Red clover may interfere with the body’s ability to process some drugs that are broken down by liver enzymes. For that reason, you should check with your doctor before taking red clover.
Estrogens, hormone replacement therapy, birth control pills — Red clover may increase the effects of estrogen.
Tamoxifen — Red clover may interfere with tamoxifen.
Anticoagulants (blood thinners) — Red clover may enhance the effect of these drugs, increasing the risk of bleeding. The same is true of herbs and supplements that have blood-thinning effects (such as ginkgo, ginger, garlic, and vitamin E).
Reviewed last on: 12/17/2008
- Steven D. Ehrlich, NMD, private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.
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