Alternative medicines and the menopause - do they work?
The popularity of alternative and complementary medicines for the management of the symptoms of menopause is unprecedented. This has been fuelled by a series of ‘scares’ hitting the headlines about the possible adverse effects of hormonal replacement therapy (HRT).
Alternative therapies are perceived by many women to be safer than HRT, and since doctors do generally not prescribe them, some women report that alternative therapies make them feel they are more in control of their health. Other reasons given for avoiding HRT include fear of cancer or side effects (such as vaginal bleeding) and the view that as the menopause is a natural transition, it requires a more ‘natural’ remedy.
Menopausal women account for one of the largest segments of alternative medicine users;
80 % of women aged 45-60 have reported using non prescription therapies for the management of menopausal symptoms. These therapies include herbal remedies, meditation, traditional Chinese medicine, vitamins and minerals, homeopathy, acupuncture and chiropractic. The regulation of alternative therapies has not kept pace with the fast growth of the industry; for example, the UK has one of the highest sales of vitamins and minerals in Europe but also the least stringent regulations.
In the USA, the 1994 dietary supplement Health and Education Act stated that dietary supplements, including herbs and vitamins, would not be considered as food, and therefore would no longer require a premarket safety evaluation. This regulation was passed in response to both consumer and manufacturer demand. Since the passing of this act, however, large discrepancies have been found between label contents and the active ingredients found in many dietary supplements. Some herbal supplements have even been found to contain unreported contaminants. A study by the Food and Drug Branch of the Californian Department of health services found that 32% of Asian patent medicines contained undeclared pharmaceuticals or heavy metals. In addition, the claims made by manufacturers of dietary supplements do not have to hold up to rigorous clinical standards. The situation is similar in Europe, where the law that should regulate the premarketing requirements for proof of safety and efficacy of food supplements is still in draft form.
To date, six randomised studies have investigated the effect of soy and other pulses on the incidence and severity of hot flushes in menopausal women (as in table above). Some of these have used soy as whole grains or in flour form. Others have utilised isolated soy protein, which is a soy-derived powder containing 90% protein and a high concentration of isoflavones that are the phytoestrogens that contained in soy. The results of the studies performed so far are contradictory. Three failed to observe any effects, while others have observed varying degrees of benefit. Soy preparations appear, at best, to nearly halve the incidences of hot flushes; this is somewhat in contrast with relatively few hot flushes experienced by Japanese women.
Four studies have performed with soy derived isoflavones on tablet or pill form at doses of 50-100 mg per day. Again, at best, the preparations reduced the number of hot flushes by half. This is not an obvious improvement on the treatments effects achieved the whole soy and suggests that the effects of these compounds is small. Thus, studies involving a large number of women, all with a high incidence of severe hot flushes, are needed to obtain as effect that is statistically significant. Two additional studies looked at the effects of soy isoflavones on women with breast cancer who complained of hot flushes, and found no improvement in their symptoms.
Dietary supplements derived from red clover contain additional isoflavones, formononetin and biochanin, which are not present in soy and may have different biological activity.
Most of the studies to date have been constrained by a very restricted budget. Often, there are insufficient resources available to measure the amount of isoflavones present in the product, or to check its stability and absorbability. Discrepancies between the isoflavones content are common, reinforcing the need for quality control of the isoflavone composition in these products.
Differences in the way isoflavones are metabolised may also be a factor. Those occurring naturally in most soy foods are conjugated almost exclusively to sugars; these are the ‘glycoside’ form of isoflavones. The bioavailablability of isoflavone glycosides and the mechanism of intestinal absorption of isoflavones in humans are unclear. Evidence from intestinal perfusion and in vitro
cell culture studies indicate that isoflavone glycosides are poorly absorbed and their bioavailability requires initial hydrolysis of the sugar moiety by intestinal beta-glucosidases for uptake in the peripheral circulation. It is possible that products that contain mostly isoflavones in the glycoside state, such as soy and red clover, may be less effective as they may be less absorbed or more susceptible to variations of individual metabolisms. Many studies do not specify the quantity of isoflavones that are present in the most active, ‘aglycone’; form and this may introduce another major form of bias in the results.
Last, but not least, the traditional Japanese diet is not only rich in soy (and hence in isoflavones) but also has a low ratio of n-6 polyunsaturated fatty acids (PUFAs) to n-3 PUFAs due to the high consumption of fish. Fish are very rich in isoflavones and also in omega-3. Although many of the benefits generally attributed to soy can also be extended to omega-3 fatty acid, the effect of the combination of isoflavones and omega-3 fatty acids has never been tested.
Randomised,controlled studies with red clover
Num of patient
Design and duration
Effect on hot flushes
|Knight et al
||Parallel, 12 weeks
|Van de Weijer et al
||Parallel, 12 weeks
Effects of phytoestrogens on bone
Four short-term (six-month) human studies have examined the effects of phytoestrogens preparations on bone mineral density, and one study has been performed on bone markets. The effects have generally been mild, but promising. One recently published, well- conducted, interventional study on pure genistein, the main phytoestrogen present in soy, at a dose of 54 mg per day, observed a highly statistically significant increase in bone mineral density of over 3% in both spine and the femoral neck. The incrementation was similar to that observed with HRT.
Other remedies used in the menopause
Black cohosh (cimicifuga racemosa)
is an indigenous plant from the east of North America that has been used by the Native Americans for gynaecological conditions since before the arrival of European settlers. It was called ‘squaw root’, because it was used primarily for female disorders. It was the primary ingredient of a tonic for ‘female complaints’, which sold widely in the USA for more than 50 years in the early 20th century. In 1989 the German government commissioned an expert panel to address herbal products, and black cohosh was approved as a non-prescription medicine for the treatment of climacteric ailments. However, the commission recommended its use for no longer than six months due to the uncertainty about its possible long-term side effects.
The treatment of menopausal signs and symptoms has been the primary therapeutic application of black cohosh. It is the main ingredient in the often used under the counter menopausal preparation, Remifemin (Schaper &Brummer, Germany)
The mechanism by which black cohosh exerts its effects is unclear. It was once believed to have oestrogen like activity, but the results of the studies have been varied. The biologically active component in black cohosh is attributed to a number of triterpene glycosides. Remifemin is standardised with respect to triterpene glycosides content. There have been only two randomised-controlled studies on the effects of black cohosh on hot flushes, and in only one was there a statistically significant reduction of symptoms.
A note of caution about the use of preparations containing black cohosh has to be made, as there have been reports of acute hepatitis in relation to its use.
Dong quai is a herb native to eastern Asia and China. It has been used for more than 1,000 years as a spice, tonic and medicine in traditional Chinese medicine. Dong Quai is known as the ‘female ginseng’ and is currently the second best selling herb in China. It is indicated for dysmenorrhoea, irregular menstruation and as a supportive herb for menopausal complaints. In the west, Dong quai has become popular as a herb for treating menopausal symptoms. One randomised placebo-controlled study has so far been performed on this compound and found no effects.
Dong quai is one of the first alternative therapies to which potentially adverse effects have been attributed, as it potentiates the effects of warfarin. Dong quai contains furocoumarins, which are coumarin- like substances that act as anticoagulants.
Evening primrose oil
Native Americans consumed leaves, roots and seedpods of evening primrose (oenothera biennis)
for food, and used extracts from it to treat a number of conditions. Today, the flowers and seeds are pressed to make an oil that is high in the omega-6 fatty acid, gamma-linolenic acid (known as GLA), and is essential polyunsaturated fatty acids, which convert into prostaglandins. Evening primrose oil is also a good source in linoleic acid. Although there are a number of good studies in which evening primrose oil has been used to successfully treat eczema and several other conditions with few side effects, it appears to have no benefit of placebo for hot flushes.
The effects of the most common supplements used for the treatment of hot flushes are mild at best. Clinical data about efficacy of these compounds are scarce and contradictory. They are usually sold directly to consumers, and health claims used for marketing purposes do not require any rigorous scientific evidence. Phytoestrogens have the largest amount of data available. The structural similarity between the isoflavones contained in soy and oestrogen has perhaps made association between soy consumption and the low incidence of hot flushes in Japanese women easier to understand. This may prove to be too simplistic, as it is highly likely that a combination of nutrients, rather than just one compound, may determine the favourable health effects of the traditional Japanese diet. The lack of regulation does not facilitate the clarification on the safety of these compounds. Patients tend to associate these products with a lack of adverse events, which tend not to be reported. Furthermore, given the general laxity in quality control of both doses and contaminants, it is generally difficult to pinpoint actual substances causing adverse event. This calls for urgent regulatory attention, as food supplements are one of the fastest expanding areas in consumer markets in the western world.
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- Discrepancies between the isoflavones content claimed by the manufacturers and the actual content are common.
- Menopausal women account for one of the largest segments of alternative- medicine users. These therapies include herbal remedies, meditation, traditional Chinese medicine, vitamins and minerals, homeopathy, acupuncture and chiropractic.
- The regulation of alternative therapies has not kept pace with the fast growth of the industry. The UK has one of the highest sales of vitamins and minerals in Europe, along with the largest stringent regulations.
- The effect of the most common supplements used for the treatment of hot flushes are mild at best. Clinical data about their efficiency is scarce and contradictory.