SHORT-TERM EFFECTS OF PHYTOESTROGEN-RICH DIET ON POSTMENOPAUSAL WOMEN

Experimental and epidemiologic evidence support the hypothesis that ph ytoestrogens have both estrogenic and antiestrogenic effects in humans . The authors investigated the effects of short-term (12 weeks) dietar y intervention with phytoestrogen-rich diet on menopausal symptoms and serum levels of phytoestrogens and sex hormone-binding globulin (SHBG ). One hundred forty-five women with climacteric complaints were assig ned randomly to a phytoestrogen-rich diet group or a control group. Th e phytoestrogen group (n = 78) ate daily portions of phytoestrogen-ric h food as a substitute for approximately one fourth of their caloric i ntake. The test diet consisted of soybean food and flax seeds, both kn own to contain high concentrations of phytoestrogenic compounds (isofl avones and lignans), The daily intake of phy toestrogen rich products included tofu, soy drink, mise, and flax seed. The subjects in the con trol group (n = 36) ate a regular (omnivorous) Israeli diet and did no t receive any hormonal treatment. Baseline and end-of-study examinatio ns included: body weight, a subjective assessment of menopausal sympto ms using a menopause symptoms questionnaire, determination of serum es tradiol, luteinizing hormone, follicle-stimulating hormone, SHGB, and phytoestrogens (enterodiol, enterolactone, equol, daidzein, O-desmethy langolensin, and genistein). The serum levels of phytoestrogens signif icantly increased in most of the subjects assigned a phytoestrogen-ric h diet, whereas the concentrations in the control group remained uncha nged, Marked increase in serum levels of SHGB was observed in the phyt oestrogen-rich diet group (from 55.8 +/- 7.09 nmol/L to 71.2 +/- 6.56 nmol/L, p < 0.003) whereas a slight insignificant decrease (from 57.4 +/- 9.2 nmol/L to 53.4 +/- 8.7 nmol/L) was found in the controls. The total score of menopausal symptomatology was reduced significantly in both groups. There appeared to be an overall greater improvement in th e phytoestrogen-rich diet group than in the control group (from 10.65 +/- 0.6 to 5.31 +/- 0.45 vs. 9.23 +/- 0.87 to 4.79 +/- 0.71, respectiv ely), but this difference did not reach statistical significance. Howe ver, when analyzed separately, the reductions in hot flashes and vagin al dryness scores were more significant (p = 0.004 and 0.005, respecti vely) in the women assigned a phytoestrogen-rich diet than in the cont rols, The authors conclude that 12 weeks' partial substitution of omni vorous postmenopausal women with phytoestrogen-rich food increases the ir serum levels of SHBG. It may alleviate symptoms such as hot flashes and vaginal dryness, Long-term effects on bone density and heart dise ase remain to be determined. cancer-Hot flushes-MenopausePhytoestrogen s-Sex hormone binding globulin.