Red clover: benefits, dosage, contraindications
Other name(s)
Meadow clover, purple clover
Scientific name(s)
Trifolium pratense
Family or group:
Plants
Active ingredients:
Coumarins
Phytoestrogens
Apigenin
Isoflavones
Indications
Scoring methodology
EFSA approval.
Osteoporosis ✪✪✪✪✪
Menopause is associated with an increased risk in women of developing osteoporosis, that is, a significant loss of bone.nnA double-blind, randomized, placebo-controlled clinical trial involved 177 women who took, for one year, a standardized extract (43.5 mg of isoflavones per day) or a placebo. Compared with placebo, the isoflavone extract significantly reduced bone loss.nnHowever, most clinical evidence suggests that taking red clover does not improve measures related to osteoporosis. Another clinical trial shows that taking a specific red clover extract providing 40 mg of isoflavones per day for one year does not significantly increase hip bone mineral density, but reduces lumbar spine bone density loss in women aged 49 to 65.nnThe benefit is unclear; more studies are needed to understand the mechanisms.nn
Posologie
Oral administration
30 - 80 mg
1 - years
Standardized isoflavone extract
Effect of an isoflavones-containing red clover preparation and alkaline supplementation on bone metabolism in ovariectomized rats.
Effects of phytoestrogenic isoflavones from red clover (Trifolium pratense L.) on experimental osteoporosis.
The effects of phytoestrogen isoflavones on bone density in women: a double-blind, randomized, placebo-controlled trial.
Dyslipidemia ✪✪✪✪✪
Results are contradictory, but clinical studies show that taking a red clover extract providing 80 mg of isoflavones per day may reduce total cholesterol and LDL in postmenopausal women with a high body mass index (BMI).nn
Posologie
Oral administration
50 - 200 mg
18 months
standardized isoflavone extract
Red clover isoflavones enriched with formononetin lower serum LDL cholesterol-a randomized, double-blind, placebo-controlled study.
A biochanin-enriched isoflavone from red clover lowers LDL cholesterol in men.
Menopause ✪✪✪✪✪
Studies have shown that red clover, thanks to its isoflavones, can help stimulate low levels of estrogen in the body, particularly during menopause in women. Under these conditions, researchers have demonstrated that an isoflavone-rich extract, which mimics the effects of estrogen (estrogen-like effects) in the body, could relieve some menopausal symptoms and thus be used in hormone replacement therapy. nnFurthermore, due to ovarian insufficiency, postmenopausal women tend to develop a more atherogenic profile. Red clover extracts have a beneficial effect on the lipid profile. Indeed, several studies have found that consumption of red clover by perimenopausal and postmenopausal women results in a significant decrease in total cholesterol, low-density lipoprotein cholesterol (LDL-C) and triglycerides, as well as a significant increase in HDL-C.nnHowever, several clinical trials show that taking oral red clover extract for 12 weeks to one year does not significantly reduce menopausal symptoms such as hot flashes or night sweats. Nevertheless, some data indicate that taking a specific red clover supplement containing a high proportion of the constituents biochanin A and genistein may offer some benefit. Thus, taking 80 mg of red clover isoflavones per day reduces menopausal symptoms compared with placebo.nn
Posologie
Orally
80 - 160 mg
1 - years
isoflavone-standardized extract
Combined Red Clover isoflavones and probiotics potently reduce menopausal vasomotor symptoms.
Clinical effects of a proprietary combination isoflavone nutritional supplement in menopausal women: a pilot trial.
Isoflavones from red clover (Promensil) significantly reduce menopausal hot flush symptoms compared with placebo.
The effect of red clover isoflavones on menopausal symptoms, lipids and vaginal cytology in menopausal women: a randomized, double-blind, placebo-controlled study.
Properties
Estrogenic action
Isoflavone constituents, biochanin A and genistein, have been reported as having relatively high levels of estrogenic activity. Daidzein appears to be less active. However, biochanin A, formononetin, genistein and daidzein have no observable progestogenic or androgenic effects. nnIsoflavones, such as those in red clover, are considered phytoestrogens, plant compounds whose structure is similar to that of estradiol and that are capable of binding to estrogen receptors. Isoflavones therefore have activity similar to estrogens and bind preferentially to the estrogen receptor beta, but with a much lower affinity than estradiol. nnBiochanin A is converted to genistein and formononetin is converted to daidzein. Genistein has a binding affinity 20 to 30 times greater for the estrogen receptor beta compared with the estrogen receptor alpha. Estrogen receptor beta is found in the vascular system, the brain, the bones and the heart, as opposed to estrogen receptor alpha which is found in the ovaries, the breast, the uterus and the adrenal glands.nn
Usages associés
Bone density
In animal research, the isoflavones genistein and daidzein stimulated osteoblastic function. According to research conducted in postmenopausal women, it is unclear to what extent bone loss is affected by dietary isoflavones such as those found in red clover. Some trials nevertheless report a small attenuation (less than 5%) in the rate of lumbar bone mineral density loss in women after supplementation with red clover extract. This supplementation does not appear to significantly affect bone mass or the rate of bone loss.nn
Usages associés
Cardiovascular
Multiple studies show that red clover may help in the prevention and treatment of heart disease. In fact, some scientific studies have found that it notably reduces LDL cholesterol (bad). Interestingly, the isoflavones present in red clover may increase HDL, or good cholesterol, in both pre- and postmenopausal women.
Usages associés
Antioxidant
The antioxidant properties of red clover have been attributed to the isoflavone genistein. Genistein inhibits the formation of hydrogen peroxide and superoxide anion and scavenges hydrogen peroxide in vitro. Daidzein also appears to have antioxidant properties, although to a lesser extent.
Dermatological effect
In human research, the topical co-administration of a red clover flower extract and a biomimetic peptide positively altered the proportion of anagen and telogen hair growth in people with alopecia. According to the researchers, the presumed mechanisms of action include reduction of inflammatory responses, inhibition of 5-alpha-reductase activity, and local stimulation of the synthesis of extracellular matrix proteins of the hair follicle.
Safe dosage
Adult: 250 mg - 500 mg
Supplementation with red clover extract provides 40 mg of total isoflavones taken once daily, or two doses totaling 80 mg of isoflavones per day. Assuming red clover extracts contain 8% isoflavones, that brings the dosages to 500 mg. It should be noted that all dosages in the studies refer to the isoflavones contained in red clover extracts. Therefore, virtually all extracts studied are standardized for isoflavones.
Interactions
Médicaments
Oral contraceptives: low interaction
Some birth control pills contain estrogen. Red clover may exert activity similar to estrogens. However, red clover is not as potent as the estrogens in birth control pills. Taking red clover with birth control pills might reduce their effectiveness. Examples of such birth control pills include: ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone.
Estrogens: low interaction
Taking red clover with estrogen pills may reduce their effects. Examples of such estrogen pills include: conjugated equine estrogens (Premarin), ethinyl estradiol, and estradiol.
Tamoxifen: low interaction
Estrogen-sensitive cancers are cancers that are affected by estrogen levels in the body. Tamoxifen (Nolvadex) is used to help treat and prevent these types of cancer. Red clover also appears to affect estrogen levels in the body. By affecting estrogen levels, red clover might reduce the effectiveness of tamoxifen (Nolvadex). Do not take red clover if you are taking tamoxifen (Nolvadex).
Methotrexate: low interaction
Red clover may increase methotrexate levels in the body and potentially increase methotrexate's side effects, such as vomiting and stomach pain.
Precautions
Breast cancer: use with caution
Red clover may act like estrogens.
Hormone-sensitive disease: use with caution
Red clover may act like estrogens.
Protein S deficiency: avoid
People with Protein S deficiency have an increased risk of blood clots. Because red clover acts like an estrogen, red clover could increase the risk of blood clots.
Surgical intervention: avoid
Red clover may slow blood clotting. It could increase the risk of heavy bleeding during and after surgery. It is advised to stop taking red clover at least two weeks prior to surgery.
Pregnancy: avoid
Red clover acts like an estrogen and could disrupt the balance of important hormones during pregnancy or breastfeeding. Avoid any use.
Breastfeeding: avoid
Red clover acts like an estrogen and may disrupt the balance of important hormones during pregnancy or breastfeeding. Avoid any use.
