Isoflavone-rich soy protein isolate attenuates bone loss in the lumbar spine of perimenopausal women

• Published in: The American journal of clinical nutrition Vol. 72; no. 3; pp. 844 - 852
• Main Authors: Alekel, D Lee, Germain, Alison St, Peterson, Charles T, Hanson, Kathy B, Stewart, Jeanne W, Toda, Toshiya
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Bethesda, MD American Society for Clinical Nutrition 01.09.2000; American Society for Clinical Nutrition, Inc
• Subjects: Adult; Biological and medical sciences; Biomarkers; Bone and Bones; Bone and Bones - metabolism; Bones; Diet; Diseases of the osteoarticular system; Double-Blind Method; drug effects; Female; human health and safety; human nutrition; Humans; Isoflavones; Isoflavones - pharmacology; Lumbar Vertebrae; Lumbar Vertebrae - drug effects; Medical sciences; medicine; metabolism; Middle Aged; Osteoporosis; Osteoporosis - prevention & control; Osteoporosis, Postmenopausal; Osteoporosis, Postmenopausal - prevention & control; Osteoporosis. Osteomalacia. Paget disease; Patient Compliance; pharmacology; Premenopause; prevention & control; Proteins; Soybean Proteins; Soybean Proteins - pharmacology; Soybeans; Women; Human; Lumbar spine; Menopause; Diseases of the osteoarticular system; Biological marker; Resorption; Bone disease; Supplemented diet; Density; Inorganic element; Flavonoid; Feeding; Osteoarticular system; Soy protein; Prevention; Osteoporosis; Plant origin; Female; Bone defect; Bone
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/72.3.844

No published studies have directly examined the effect of soy protein with isoflavones on bone or bone turnover in perimenopausal women. Our objective was to determine the effects of 24 wk of consumption of soy protein isolate with isoflavones (80.4 mg/d) in attenuating bone loss during the menopausal transition. Perimenopausal subjects were randomly assigned, double blind, to treatment: isoflavone-rich soy (SPI+; n = 24), isoflavone-poor soy (SPI-; n = 24), or whey (control; n = 21) protein. At baseline and posttreatment, lumbar spine bone mineral density (BMD) and bone mineral content (BMC) were measured by using dual-energy X-ray absorptiometry. At baseline, midtreatment, and posttreatment, urinary N:-telopeptides and serum bone-specific alkaline phosphatase (BAP) were measured. The percentage change in lumbar spine BMD and BMC, respectively, did not differ from zero in the SPI+ or SPI- groups, but loss occurred in the control group (-1.28%, P: = 0.0041; -1.73%, P: = 0.0037). By regression analysis, SPI+ treatment had a positive effect on change in BMD (5.6%; P: = 0.023) and BMC (10.1%; P: = 0.0032). Baseline BMD and BMC (P: < or = 0.0001) negatively affected the percentage change in their respective models; baseline body weight (P: = 0.0036) and bone-free lean weight (P: = 0.016) contributed positively to percentage change in BMD and BMC, respectively. Serum BAP posttreatment was negatively related to percentage change in BMD (P: = 0.0016) and BMC (P: = 0.019). Contrast coding using analyses of covariance with BMD or BMC as the outcome showed that isoflavones, not soy protein, exerted the effect. Soy isoflavones attenuated bone loss from the lumbar spine in perimenopausal women.