Oestrogenic Effects of Plant Foods in Postmenopausal Women

This section is compiled by Frank M. Painter, D.C.
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FROM:   British Medical Journal 1990 (Oct 20); 301 (6757): 905–906 ~ FULL TEXT

G Wilcox, M L Wahlqvist, H G Burger, and G Medley

Monash University Department of Medicine,
Prince Henry's Hospital,
Melbourne, Victoria, Australia.

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From the FULL TEXT Article:

Introduction

Crops grown as animal pasture are known to have oestrogenic activity, [1] and some foods contain potential oestrogenic analogues such as the isoflavonoids (isoflavones and coumestans), lignans, and resorcyclic acid lactones, [2] which may be activated or inactivated. [3] We studied the effect of three foods reported to induce vaginal oestrus in laboratory animals [4] in postmenopausal women not taking oestrogen replacement therapy.

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Subjects, methods, and results

We studied 25 postmenopausal women who were non-smokers, in good general health, and taking no drugs known to affect oestrogen state (mean age 59 (range 51–70); body mass index 24.4 (range 18.7–31.6) kg/m²; years after menopause 8.1 (range 1–20)). The protocol was a latin square design with a two week run in period and a six week experimental period. The women recorded their normal diet for 14 days and were asked to repeat the fortnightly diet throughout the study. During the experimental period the diet was supplemented with soya flour (45 g daily), red clover sprouts (10 g dry seed daily), and linseed (25 g daily), each for two weeks in turn. To check compliance the women returned residual food. Blood samples were taken weekly and lateral wall vaginal smears taken fortnightly and at follow up two and eight weeks after supplementation finished. Analysis was on intention to treat, but 23 women completed the study.

Table 1

We examined the dependent variables vaginal cell maturation and serum concentrations of luteinising hormone and follicle stimulating hormone. The cumulative effects of the three foods at six weeks were compared with baseline by the paired t test, as were the residual effects, two and eight weeks after the last food supplement. We found significant differences in vaginal cytology after six weeks' supplementation (p<001, 95% confidence interval 6.0 to 17.6), which persisted for two weeks after treatment (p<002), but cytology returned to baseline after eight weeks (Table). sources of oestrogenic activity. Conversely, tamoxifen, an antioestrogen, can have oestrogenic effects on vaginal cytology. [5]

Patterns of food intake may modulate the severity of the menopause as it is an oestrogen deficiency state. Up to half of the diet of some populations may comprise foods containing phyto-oestrogens, whereas in our study such foods comprised only about 10% of energy intake for a fairly short time. Whether menopausal symptoms differ in such populations would be worth investigation.

We thank our statistical adviser, Steve Farrish, from the department of social and preventive medicine, Monash University.

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References:

1. Schutt DA.
   The effects of plant oestrogens on animal reproduction.
   Endeavour 1976;35: 110-3.

2. Pnrce KR, Fenwick GR.
   Naturally occurring oestrogens in foods-a review.
   FoodAddit Contam 1985;2:73-106.

3. Adlercreutz H, Fotsis T, Bannwart C, et al.
   Determination of urinary lignans and phytoestrogen metabolites, potential antiestrogens
   and anticarcinogens, in urine of women on various habitual diets.
   J Steroid Biochem 1986;25:797.

4. Farnsworth NR, Bingel AS, Cordell GA, Crane FA, Fong HHS.
   Potential value of plants as sources of new antifertility agents. 2
   J Pharm Sci 1975;64:717-54.

5. Ferrazzi E, Cartei G, Mattarazzo R, Fiorentino M.
   Oestrogen-like effect of tamoxifen on the vaginal epithelium.
   BrMedJ 1977; i: 1351-2.

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