Title: The dietary management of menopausal hot flushes

 

Key words: menopause, menopausal, hot flushes, nutrition, dietary interventions, soybean, soya beans, phytoestrogens, oestrogen, progesterone, isoflavones, oestrogen receptors, HRT, breast cancer, natural soya, soya isolates, black cohosh, herb, Chinese herbs, clover, agnus castus, dong quai, cardiovascular events, exercise, fresh vegetables, fruit, spices, coffee, alcohol, antioxidants, vitamin E, mineral, supplementation, cancer,  

 

Date: Oct 2006

 

Category: Special diets, Specific conditions

 

Nutrimed Module:

 

Type: Article

 

Author: Morgan, G

 

The dietary management of menopausal hot flushes

The menopause is associated with a range of physiological and psychological disturbances, of which hot flushes are one of the most prevalent, inconveniencing and distressing. This review will look at some of the dietary interventions that have been employed in the management of this condition. That nutrition may play an important part in the aetiology of hot flushes is demonstrated by its relatively low incidence in certain cultures. The Chinese, Japanese and Korean are the best examples, rates of hot flushes in these cultures being as low as 25%, compared with the 85% in the West (Lock 1998). The high consumption of soybean products is thought to be responsible, as migrants to the West who adopt Western eating patterns acquire the much higher levels of hot flushes found amongst Western women.

 

Much research has focussed on the hormonal changes associated with the menopause and the possible role of phytoestrogens, present in soya-based products, in correcting these disturbances ( Kurzer 2000). Low menopausal oestrogen and progesterone levels explain the efficacy of hormone replacement treatment (HRT) for hot flushes, and also of natural progesterone therapy (Leonetti 1999). Phytoestrogens, such as soya-based isoflavones, are thought to act as weak oestrogens (Cassidy 1994). They also partly act as anti-oestrogens by blocking oestrogen receptors, thus blocking some of the harmful effects of oestrogen, such as an increased rate of breast cancer (Glazier 2001).

 

Research into the efficacy of isoflavones has been hampered by the high placebo rates, poor study design and the underpowered nature of many of the trials. The trials have been reviewed by Kronenberg (Kronenberg 2002). Accepting that trials should be double-blind and run for at least 6 weeks, only 3 trials out of 8 showed a favourable effect on hot flushes (Brzezinski 1997, Albertazzi 1998, Han 2002). One well-controlled trial lasting 24 weeks gave a negative result (St Germaine 2001). The conclusion of this review was that soya-based isoflavones, in doses of at least 40 mgs a day, exhibited a favourable effect on hot flushes, preparations from natural soya being more beneficial than from soya isolates. This review also reported a favourable effect of black cohosh in three out of the four trials reported on (Stoll 1987, Lehmann-Willenbrock 1988, Jakobson 2001) . One other report showed a beneficial effect (Liebermann 1998). The precise mode of action of this herb is unknown. There have been no beneficial effects from other herbs, including red clover, agnus castus, dong guai and combinations of Chinese herbs, as judged by controlled trials (Kronenberg 2002).

 

In general, these trials have produced less favourable results than HRT in the treatment of hot flushes. There is, however, some debate over the efficacy of HRT itself and it is now clear, from the results of the US Women’s Health Initiative, that the incidence of breast cancer (Coldiz 1995) and cardiovascular events (Jick 1996) increase with its use, to a level where its routine use can no longer be justified. This is reflected in the increased concern expressed by menopausal women over HRT and their desire to use natural products if at all possible. Increasing attention has therefore concentrated on efforts to improve the general level of well-being of this group of women by encouraging exercise, relaxation measures, and the increased consumption of fresh fruit and vegetables. Removal of triggering factors, such as spices, coffee and alcohol, has also been found to be helpful. Increased antioxidant intake, through adopting a healthier dietary lifestyle, has been linked to reduced rates of cardiovascular disease and cancer and this, together with vitamin and mineral supplementation, is to be encouraged from an earlier age.

 

One trial showed a beneficial effect of taking 800 i.u. of vitamin E a day in treating hot flushes (Barton 1998), and other favourable responses have been achieved with vitamin C and bioflavanoids (Smith 1964). Soya-based isoflavones, as well as their hormonal effects, also possess antioxidant properties, and some of their beneficial effect in treating hot flushes may de due to this effect. All these agents have been linked to reduced rates of obesity, cardiovascular disease and cancer, as well as helping menopause-related problems.

 

Further research needs to be carried out on probiotics: their use may increase the generation of equol, an active metabolite of the dietary isoflavone diadzein present in soya products, as well as possessing beneficial cardiovascular and anti-cancer effects (Setchell 2002). There are no contraindications to probiotics, soya or other nutritional products. Their use, in combination with other lifestyle measures, would appear to offer the best way forward in the management of hot flushes associated with the menopause.

 

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