Red Clover Toxicity

The flowers, sprouts and leaves of the red clover plant are generally considered to be safe for human ingestion. The National Center for Complementary and Alternative Medicine (NCCAM) notes that red clover supplements are generally safe and well-tolerated. However, some experts have expressed concern about the estrogen-like compounds found in red clover flowers; the plant's sprouts also contain a weak toxin.

Phytoestrogens

• Like many other medicinal herbs, red clover contains phytoestrogens--plant-like compounds chemically similar to the animal hormone estrogen. NCCAM notes that, in theory, long-term use of red clover supplements could increase the risk of endometrial cancer.

Canavanine Content

• In January 2004, the "Journal of Food Protection" published a review stating that the seeds and sprouts of the red clover plant contain detectable amounts of the amino acid canavanine. This compound is also found in alfalfa sprouts.

Canavanine Toxicity

• The October 2007 edition of "Methods in Molecular Biology" reported that canavanine may cause abnormal autoimmune responses. The abnormalities caused by high doses of canavanine are similar to those seen in people suffering from lupus.

Considerations

• Concerns related to clover-based phytoestrogens and canavanine are theoretical. According to NCCAM, there are no reports of serious side effects from red clover. Because red clover was historically used as a primary food source with no reports of toxicity, an overdose of red clover is unlikely.

Warning

• Because red clover may exert a weak effect on the female endocrine system, experts caution against using high doses during pregnancy and lactation. In theory, it may also contribute to the growth of hormone-sensitive cancers including breast and ovarian cancer.