Scientific Program (Oral Abstracts) | Poster Abstracts | Speaker List
SECOND INTERNATIONAL SYMPOSIUM
ON THE ROLE OF SOY
IN PREVENTING AND TREATING CHRONIC DISEASESeptember 15-18, 1996
Brussells, Belgium
SCIENTIFIC PROGRAM
(Oral Abstracts)Hormonal effects of Soy
Premenopausal StudiesHormonal Effects of Isoflavones in Humans
Aedin Cassidy.
Centre for Nutrition and Food Safety, School of Biological Sciences.
University of Surrey, Guildford GU2 5XH, Surrey, England.The hormonal effects of consumption of various soy products was examined in 15 premenopausal women, 6 postmenopausal women and 6 middle-aged men.
The 15 premenopausal women were studied over a 9-month period, during which time they lived in a metabolic suite so that their activities and diet could be kept constant. Their hormonal status was measured over 2 or 3 complete menstrual cycles. During one menstrual cycle a normal but constant diet containing no soybean products was fed. Over a second menstrual cycle, 6 subjects consumed 60g/d TVP, 3 subjects ate 50g/d miso, while 6 others consumed 28g/d TVP. 5 of these subjects completed a third diet period where they were randomly assigned to consume the control diet or Arcon F 60 g/d. Follicular phase length was significantly increased (p<0.01) and peak progesterone concentrations were delayed with 60g/d TVP and this delay was significant for miso (p<0.05). Mid-cycle surges of LH and FSH were suppressed with 60g/d TVP (p<0.05 and p<0.01 respectively). Total cholesterol levels were significantly reduced on the TVP 60g/d diet. The half dose TVP diet and the Arcon F diet had no effect on menstrual cycle regulation nor on hormonal status.
The postmenopausal women and middle-aged men were studied under 'free-living' conditions, where they lived at home during the 4-week duration of the study. Subjects consumed 60g/d TVP which was incorporated into bread rolls together with a known amount of PABA to monitor subject compliance with the dietary supplement. LH levels were significantly suppressed in the postmenopausal women (p<0.01) but no significant effect on FSH was observed. Total cholesterol, LDL and HDL levels did not change significantly over the 4 week diet period. In the men, the soy diet had no effect on LH, FSH, total cholesterol, LDL or HDL levels. Intakes of dietary protein and NSP were increased between habitual diet and intervention period, and these effects, together with other potential confounding variables inherent in 'free-living' studies may in part explain the limited biological effects observed.Under controlled conditions, we showed the isoflavones are biologically active in premenopausal women, and appear to act as weak oestrogens. More controlled studies are required to further examine the effects of isoflavones in men and post menopausal women.
Soy Symposium Home http://soyfoods.com/symposium/
U.S. Soyfoods Directory Home http:soyfoods.com/
© Copyright 1997
Indiana Soybean Board