The Effect of Soy Food Intake on Mineral Status in Premenopausal Women

Background: Soy foods have been substituted for meat in recent years because of proposed health benefits. Research indicates, however, that soy protein and phytate in soy products inhibit the absorption of divalent cations. Methods: Our study was primarily designed to determine the effect of consuming two to three servings per day of soy foods, providing *19 g protein and *36 mg isoflavones, on iron and zinc status in premenopausal women during a 10-weeks period. As secondary outcomes, we also tested the effect of soy foods on biochemical markers of bone and thyroid hormones. Nonsmoking women (18–28 years) without chronic disease, anemia, pregnancy, or irregular menstrual cycles were randomly assigned to either the soy food (SF, n = 31) or animal food (AF, n = 32) group. Blood and urine samples and 3-day dietary records were collected at baseline and postintervention. Results: At baseline, iron and zinc status, bone markers, and thyroid hormones were not different between groups. After intervention, no significant changes were observed in hemoglobin, transferrin saturation, serum iron, ferritin, or transferrin receptor (TFR) concentrations. Plasma zinc, but not serum alkaline phosphatase, significantly decreased in both groups ( - 0.8 lmol/L). The change in bone-specific alkaline phosphatase was significant between SF (1.5 U/L) and AF ( - 0.7 U/L) groups. No significant changes were observed in bone resorption, thyroid-stimulating hormone (TSH), or free thyroxine after soy food intake. Conclusions: Incorporating *19 g soy protein from soy foods for 10 weeks had no significant effect on iron or zinc status, bone resorption or formation, or thyroid hormone status in premenopausal women

Impact of Protein Supplements on Muscle Recovery After Exercise-induced Muscle Soreness

The intent of this study was to determine whether nutritional supplements [protein (0.4 g·kg−1) vs. carbohydrate (0.4 g·kg−1) vs. placebo] would affect muscle recovery differently after eccentric exercise-induced muscle soreness in untrained healthy young men (n = 21) aged 20-28 years. During this double-blind randomized block study design, each subject completed three, 3-day trials (separated by = 2 weeks), identical except for treatment, with each subject serving as his own control. Trials began with a bout of right-leg eccentric exercise (Biodex), followed directly by treatment. At 0 (baseline), 24 and 48 hours, data were collected: creatine phosphokinase from pre-exercise blood samples, subjective muscle soreness questions, and strength tests (power, torque, work). ANOVA indicated that exercise caused mild muscle damage, as evidenced by an overall day effect (p = 0.0001) for muscle soreness, with the lowest median values (0-10 scale) on day 1 (0.7), increasing (p = 0.0001) on day 2 (3.2), and remaining elevated on day 3 (3.4). We also noted an overall day effect (p = 0.0001) for creatine phosphokinase, with the lowest median values on day 1 (136 U·L-1), increasing (p = 0.0001) on day 2 (235 U·L-1), and remaining elevated on day 3 (189 U·L-1). ANOVA revealed no significant treatment effect on indicators of soreness or damage during recovery. Our results indicated that protein or carbohydrate supplement after exercise that caused mild muscle damage did not facilitate muscle recovery in adequately nourished, healthy young men

The effect of soy isoflavone on bone mineral density in postmenopausal Taiwanese women with bone loss: a 2-year randomized double-blind placebo-controlled study

[[abstract]]The treatment of 300-mg/day isoflavones (aglycone equivalents) (172.5 mg genistein+127.5 mg daidzein) for 2 years failed to prevent lumbar spine and total proximal femur bone mineral density (BMD) from declining as compared with the placebo group in a randomized, double-blind, two-arm designed study enrolling 431 postmenopausal women 45–65 years old. Introduction This study evaluated the effects of soy isoflavones on bone metabolism in postmenopausal women. Methods Four hundred and thirty-one women, aged 45–65 years, orally consumed 300-mg/day isoflavones (aglycone equivalents) or a placebo for 2 years in a parallel group, randomized, double-blind, two-armstudy. Each participant also ingested 600 mg of calcium and 125 IU of vitamin D3 per day. The BMD of the lumbar spine and total proximal femur were measured using dual-energy X-ray absorptiometry at baseline and every half-year thereafter. Serum bone-specific alkaline phosphatase, urinary N-telopeptide of type 1 collagen/creatinine, and other safety assessments were examined regularly. Results Two hundred out of 217 subjects in the isoflavone group and 199 out of 214 cases in placebo group completed the treatment. Serum concentrations of isoflavone metabolites, genistein and daidzein, of the intervention group were remarkably elevated following intake of isoflavones (p< 0.001). However, differences in the mean percentage changes of BMD throughout the treatment period were not statistically significant (lumbar spine, p=0.42; total femur, p=0.39) between the isoflavone and placebo groups, according to the generalized estimating equation (GEE) method. A significant time trend of bone loss was observed at both sites as assessed by the GEE method following repeated measurement of BMD (p<0.001). Differences in bone marker levels were not significant between the two treatment groups

Association of Oxidative Stress, Iron, and Centralized Fat Mass in Healthy Postmenopausal Women

Objective: Centralized adiposity, insulin resistance, excess iron, and elevated oxidative stress place postmenopausal women at risk for atherosclerotic cardiovascular disease (CVD). The objective of this study was to determine the relationship among excess iron, oxidative stress, and centralized fat mass in healthy postmenopausal women. Methods: The parent project recruited healthy women for a randomized, double-blind, clinical trial designed to examine the effect of soy isoflavones on bone. At baseline ( n = 122), we measured three antioxidant enzymes, iron status indices (serum ferritin among others), oxidative stress indices (oxidized low-density lipoprotein [oxLDL], urinary isoprostanes [PGF2α], protein carbonyls, DNA damage), and waist, hip, and thigh fat mass using dual-energy x-ray absorptiometry (DXA). We calculated insulin resistance using the homeostasis model assessment (HOMA). Multiple regression analysis was used to determine the CVD risk factors that contributed to oxidative stress and centralized fat mass (waist + hip/thigh = AndGynFM ratio). Results: Almost 14% ( p This is a copy of an article published in the Journal of Women's Health © 2009 copyright Mary Ann Liebert, Inc.; Journal of Women's Health is available online at: http://online.liebertpub.com.</p

The Effect of Soy Food Intake on Mineral Status in Premenopausal Women

Background: Soy foods have been substituted for meat in recent years because of proposed health benefits. Research indicates, however, that soy protein and phytate in soy products inhibit the absorption of divalent cations. Methods: Our study was primarily designed to determine the effect of consuming two to three servings per day of soy foods, providing *19 g protein and *36 mg isoflavones, on iron and zinc status in premenopausal women during a 10-weeks period. As secondary outcomes, we also tested the effect of soy foods on biochemical markers of bone and thyroid hormones. Nonsmoking women (18–28 years) without chronic disease, anemia, pregnancy, or irregular menstrual cycles were randomly assigned to either the soy food (SF, n = 31) or animal food (AF, n = 32) group. Blood and urine samples and 3-day dietary records were collected at baseline and postintervention. Results: At baseline, iron and zinc status, bone markers, and thyroid hormones were not different between groups. After intervention, no significant changes were observed in hemoglobin, transferrin saturation, serum iron, ferritin, or transferrin receptor (TFR) concentrations. Plasma zinc, but not serum alkaline phosphatase, significantly decreased in both groups ( - 0.8 lmol/L). The change in bone-specific alkaline phosphatase was significant between SF (1.5 U/L) and AF ( - 0.7 U/L) groups. No significant changes were observed in bone resorption, thyroid-stimulating hormone (TSH), or free thyroxine after soy food intake. Conclusions: Incorporating *19 g soy protein from soy foods for 10 weeks had no significant effect on iron or zinc status, bone resorption or formation, or thyroid hormone status in premenopausal women.This is a copy of an article published in the Journal of Women's Health © 2011 copyright Mary Ann Liebert, Inc.; Journal of Women's Health is available online at: http://online.liebertpub.com.</p

Association of Oxidative Stress, Iron, and Centralized Fat Mass in Healthy Postmenopausal Women

Objective: Centralized adiposity, insulin resistance, excess iron, and elevated oxidative stress place postmenopausal women at risk for atherosclerotic cardiovascular disease (CVD). The objective of this study was to determine the relationship among excess iron, oxidative stress, and centralized fat mass in healthy postmenopausal women. Methods: The parent project recruited healthy women for a randomized, double-blind, clinical trial designed to examine the effect of soy isoflavones on bone. At baseline ( n = 122), we measured three antioxidant enzymes, iron status indices (serum ferritin among others), oxidative stress indices (oxidized low-density lipoprotein [oxLDL], urinary isoprostanes [PGF2α], protein carbonyls, DNA damage), and waist, hip, and thigh fat mass using dual-energy x-ray absorptiometry (DXA). We calculated insulin resistance using the homeostasis model assessment (HOMA). Multiple regression analysis was used to determine the CVD risk factors that contributed to oxidative stress and centralized fat mass (waist + hip/thigh = AndGynFM ratio). Results: Almost 14% ( p \u3c 0.0005) of the variability in oxLDL was accounted for by AndGynFM ratio (6.1%, p \u3c 0.0005), age (4.0%, p = 0.012), and serum iron (2.8%, p = 0.053). Similarly, 16% ( p \u3c 0.0001) of the variability in PGF2α was accounted for by the AndGynFM ratio (4.8%, p = 0.011), HOMA (3.9%, p = 0.021), and serum iron (2.7%, p = 0.054). We accounted for 33% ( p ≤ 0.0001) of the variability in AndGynFM ratio by high-density lipoprotein cholesterol (HDL-C) (4.3%, p = 0.008), ferritin (4.9%, p = 0.005), HOMA (4.5%, p = 0.006), oxLDL (2.6%, p = 0.04), and PGF2α (3.0%, p = 0.025). Conclusions: Our study suggests that reducing centralized fat mass and maintaining a favorable lipid profile, antioxidant status, and iron status all may be important in protecting postmenopausal women from atherosclerotic CVD. [ABSTRACT FROM AUTHOR