Red clover, Trifolium pratense, is a flowering plant in the Bean Family (Fabacaea). It is native to native to Europe, Western Asia, and northwest Africa, but it has been planted in gardens as both flower and herb around the world.
Red clover's phytoestrogen content makes it an attractive addition to natural medicines for the symptoms of menopause and perimenopause. These naturally occurring plant compounds interact with some of the same cell receptors as human estrogen, but they are not so potent as to be toxic. Sometimes red clover is just similar enough to estrogen replacement therapy that it controls hot flashes. For other indications, red clover is not usually taken as a stand-alone herb. It is often combined with pomegranate or soy in supportive therapy for osteoporosis.
What is the evidence that red clover is helpful in osteoporosis?
There have been at least 2000 studies of red clover as an adjunct therapy for unpleasant symptoms of menopause, and at least 35 studies of red clover in herbal formulas and lifestyle recommendations for osteoporosis. The most convincing study involved measuring bone mineral density in women before and after taking red clover extract for a year.
Researchers in Denmark recruited 85 women aged 60 to 85 to take either a red clover extract or a similarly flavored placebo for a year. This red clover product had been fermented with lactic acid bacteria (like those in yogurt, although not from dairy) to enhance absorption of the estrogen-like isoflavones. All of the women suffered osteopenia, which accelerates bone loss. All of the women in the clinical trial took several supplements: calcium (1200 mg/d), magnesium (550 mg/d), and calcitriol (25 μg/d). (Calcitriol is a synthetic version of vitamin D3.) No participant in the trial received any other osteoporosis treatments.
At the end of the year, both groups of women showed some loss of bone mineral density, but the loss of mineralization was two to four times worse in the women who were given the placebo. The women who received red clover extract had "normal" loss of bone mineral density for their age, while the women who did not receive the extract continued to have the accelerated bone mineral loss characteristic of osteopenia. The greatest difference in bone mineral loss was in the trochanter, a bone extension of the thigh bone, to which muscles are attached. Red clover extract was in this study particularly protective against hip fractures that can be accompanied by painful muscle spasms.
Laboratory studies with animals are not always generalizable to people, but there are at least good reasons to investigate whether the combination of red clover extract and dried pomegranate both protects bone and fights obesity. A Korean study found that taking the combination shrank fat cells and increased estrogen and bone-specific alkaline phosphatase levels. Science has not confirmed this combination of benefits of red clover extract in humans, but there is at least reason to suppose there could be.
Just how useful is red clover extract?
Red clover extract has some enthusiastic, knowledgeable backers.
Professor Per Bendix Jeppesen from the Department of Clinical Medicine at Aarhus University, Denmark, says that red clover extract may be the best way to avoid the toxic side effects of estrogen replacement therapy for preventing and treating osteoporosis and for managing the symptoms of menopause: “The treatment is groundbreaking, as we can now treat osteoporosis without the use of dangerous oestrogens, which introduce a significantly increased risk of cancer and other side effects." Clinical professor Niklas Rye Jørgensen, from the Department of Clinical Biochemistry, Rigshospitalet, Denmark, notes that “It could help to prevent osteoporosis around the world, but especially in less developed countries, where access to medicine can be limited. In developing countries it could be ideal to use a natural product, which is considerably cheaper to produce than conventional medicine,”
So how do you use red clover extract to support recovery from osteoporosis?
The first thing to be sure of when using red clover extract it to be sure to get a fermented extract. Don't just boil up red clover tea. It's not the same thing as a red clover extract that is produced after lengthy, natural processing. The amount of extract used in clinical trials that got positive results for women who were already known to have osteopenia was 60 ml per day. If you prefer to use dried extract in capsule form, take any product that delivers 85 mg of extract per day. (They will be identified on the label.) As little as 20 mg of extract per day is helpful, but up to 85 mg per day is helpful. If you also have weight issues, you may prefer to add dried pomegranate or pomegranate extract to your supplement routine, although pomegranate is not essential for protection against bone mineral loss. It is necessary to take red clover extract continuously for 12 weeks to see results. Do not take red clover if you take Coumadin (warfarin) or any other blood thinning medication.