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

Androidal Fat Dominates in Predicting Cardiometabolic Risk in Postmenopausal Women

We hypothesized that soy isoflavones would attenuate the anticipated increase in androidal fat mass in postmenopausal women during the 36-month treatment, and thereby favorably modify the circulating cardiometabolic risk factors: triacylglycerol, LDL-C, HDL-C, glucose, insulin, uric acid, C-reactive protein, fibrinogen, and homocysteine. We collected data on 224 healthy postmenopausal women at risk for osteoporosis (45.8–65 y, median BMI 24.5) who consumed placebo or soy isoflavones (80 or 120 mg/d) for 36 months and used longitudinal analysis to examine the contribution of isoflavone treatment, androidal fat mass, other biologic factors, and dietary quality to cardiometabolic outcomes. Except for homocysteine, each cardiometabolic outcome model was significant (overall P-values from ≤.0001 to .0028). Androidal fat mass was typically the strongest covariate in each model. Isoflavone treatment did not influence any of the outcomes. Thus, androidal fat mass, but not isoflavonetreatment, is likely to alter the cardiometabolic profile in healthy postmenopausal women

Phytoestrogens

Collectively, plants contain several different families of natural products among which are compounds with weak estrogenic or antiestrogenic activity toward mammals. These compounds, termed phytoestrogens, include certain isoflavonoids, flavonoids, stilbenes, and lignans. The best-studied dietary phytoestrogens are the soy isoflavones and the flaxseed lignans. Their perceived health beneficial properties extend beyond hormone-dependent breast and prostate cancers and osteoporosis to include cognitive function, cardiovascular disease, immunity and inflammation, and reproduction and fertility. In the future, metabolic engineering of plants could generate novel and exquisitely controlled dietary sources with which to better assess the potential health beneficial effects of phytoestrogens

Soy reduces bone turnover markers in women during early menopause: A randomized controlled trial

Menopausal estrogen loss leads to an increased bone loss. Soy isoflavones can act as selective estrogen receptor modulators, their role in bone turnover is unclear. The primary outcome was assessing changes in plasma bone turnover markers. The secondary outcomes were assessing changes in cardiovascular risk markers including insulin resistance, blood pressure and lipid profile. We performed a double blind randomised parallel study where 200 women within 2 years after the onset of their menopause were randomised to 15 g soy protein with 66mg isoflavone (SPI) or 15 g soy protein alone (SP), daily for 6 months.There was a significant reduction in type I collagen crosslinked Beta C-telopeptide (βCTX) (bone-resorption marker) with SPI supplementation (0.40 ± 0.17 vs. 0.15 ± 0.09µg/L; p<0.01) compared to SP supplementation (0.35 ± 0.12 vs. 0.35 ± 0.13µg/L; p=0.92) after 6 months. There was also a significant reduction in type I procollagen-N-propeptide (P1NP) (bone-formation marker) with SPI supplementation (50.5 ± 25.0 vs. 34.3 ± 17.6µg/L; p<0.01), more marked between 3 and 6 month. Following SPI there was a significant reduction in fasting glucose, fasting insulin, insulin resistance and systolic blood pressure whereas no significant changes in these parameters was observed with SP. There were no significant changes in fasting lipid profile and diastolic blood pressure with either preparation. There was a significant increase in TSH and reduction in free thyroxine (p<0.01) with SPI supplementation though free tri-iodothyronine was unchanged. In conclusion, soy protein with isoflavones may confer a beneficial effect on bone health, analogous to the mode of action of anti-resorptive agents albeit to a less magnitude. There was a significant improvement of cardiovascular risk markers, but a significant increase in TSH and reduction in free thyroxine after SPI supplementation indicating a detrimental effect on thyroid function

Marked Individual Variation in Isoflavone Metabolism After a Soy Challenge Can Modulate the Skeletal Effect of Isoflavones in Premenopausal Women

Soy-isoflavones may act as estrogenic agonists or antagonists depending on the endogenous hormone status. These clinical effects can be exerted variably in individuals by the metabolic ability to produce a more potent metabolite than precursors. The objective of this randomized, double-blind, placebo-controlled study was to investigate the skeletal effect of isoflavones according to their metabolic variability in premenopausal women. Volunteers were randomly assigned to receive either soy-extract isoflavones (n=32) or lactose (n=21) once a day for three menstrual cycles. After intervention, the urinary excretions of isoflavones and their metabolites were significantly higher in the soy group than in the placebo group and showed a large inter-individual variation. Women in the soy group were divided into subgroups according to their ability to excrete more potent metabolites. Serum osteocalcin and urine deoxypyridinoline showed a tendency to increase after a challenge in equol high-excretors. Serum osteocalcin concentration in the genistein high-excretors increased significantly after a challenge (P=0.04) but did not increase in either the placebo or genistein low-excretors. An estrogenic antagonistic effect of isoflavones on bone turnover was observed in premenopausal women who are able to produce more potent metabolites

Vegetable and fruit intake and its relevance with serum osteocalcin and urinary deoxypyridinoline in Korean adults

The purpose of this study was to evaluate the daily vegetable and fruit intake status of Korean adults and to examine the relationship of vegetable and fruit intake with bone metabolism. The vegetable and fruit intake of 542 healthy male and female adults was analyzed. Then, by selecting 51 targets from the subjects, the relation of vegetable and fruit intake with serum calcium, osteocalcin and deoxypyridinoline (DPD) excretion in urine was examined. The total vegetable intake per day was 397.7 g and 333.5 g by men and women respectively for the age group of 20-29, 366.9 g and 309.2 g respectively for the age group of 30-49, 378.4 g and 325.9 g respectively for the age group of 50-64. Of vegetable varieties, leafy and stem vegetables displayed the highest intake. The order of major intake items of vegetables and fruits was found to be Chinese cabbage kimchi, onion, radish, cucumber, and welsh onion for the age group of 20-29, watermelon, Chinese cabbage kimchi, peach, potato, and onion for the age group of 30-49 and watermelon, Chinese cabbage kimchi, tomato, potato, and peach for the age group of 50-64. Of 51 targets, β-carotene intake displayed a significantly negative correlation with serum osteocalcin. While caloric intake as well as protein, carbohydrate, calcium, phosphorous, zinc and total food intake displayed a significantly negative correlation with DPD excretion in urine, tuber vegetable intake displayed a significantly positive correlation with DPD excretion in urine. In the future, a study will be necessary to accurately explain the relevance of vegetable and fruit intake with bone mineral density and bone metabolism. Also, efforts will be required to increase vegetable and fruit intake

EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to soy isoflavones and maintenance of bone mineral density (ID 1655) and reduction of vasomotor symptoms associated with menopause (ID 1654, 1704, 2140, 3093, 3154, 3590) (further assessment) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

&lt;p&gt;Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to provide a scientific opinion on health claims pursuant to Article 13 of Regulation (EC) No 1924/2006 in the framework of further assessment related to soy isoflavones and maintenance of bone mineral density and reduction of vasomotor symptoms associated with menopause. The food constituent that is the subject of the claim, soy isoflavones, is sufficiently characterised. The claimed effects, maintenance of bone mineral density and reduction of vasomotor symptoms associated with menopause, which are eligible for further assessment, are beneficial physiological effects. The proposed target populations are peri- and/or post-menopausal women. On the basis of the data presented, the Panel concludes that the evidence provided is insufficient to establish a cause and effect relationship between the consumption of soy isoflavones and maintenance of bone mineral density, and between the consumption of soy isoflavones and reduction of vasomotor symptoms associated with menopause.&lt;/p&gt