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.

UNLABELLED: 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-arm study. Each participant also ingested 600 mg of calcium and 125 IU of vitamin D(3) 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. CONCLUSION: Treatment with 300-mg/day isoflavones (aglycone equivalents) failed to prevent a decline in BMD in the lumbar spine or total femur compared with the placebo group.

Interphotoreceptor retinoid-binding protein contains three retinoid binding sites.

Interphotoreceptor retinoid binding protein (IRBP), the major soluble protein component of the interphotoreceptor matrix, is believed to participate in the visual cycle by transporting retinoids between retinal pigment epithelium and photoreceptor cells in the eye. IRBP can associate with several chemical and isomeric forms of retinoids but displays the highest affinity towards the retinoids that are important in the visual cycle, 11-cis-retinal and all-trans-retinol. It was previously reported that IRBP can associate with 2 mol of all-trans-retinol or 2 mol of 11-cis-retinal per mol of protein. One of the retinoid binding sites, termed 'site 1', was found to display a broad ligand selectivity and to bind either all-trans-retinol or 11-cis-retinal with similar affinities. Here, the retinoid-binding properties of IRBP were further examined. The data demonstrate that IRBP contains three distinct retinoid binding sites. The promiscuous 'site 1', and two additional sites with a stricter selectivity. One of the latter sites appears to be selective towards all-trans-retinol, while the other is specific for 11-cis-retinal.

Bioavailability of iron from purple laver (Porphyra spp.) estimated in a rat hemoglobin regeneration bioassay.

Laver belongs to the genius of Porphyra and is the most valuable seaweed in the aqua-culture industry. It contains higher iron than many other plant foods. The bioavailability of iron from laver was evaluated in a rat hemoglobin regeneration assay. Reagent-grade ferrous sulfate was used as the reference standard, and the relative biological value (RBV) for laver was expressed as a percentage of the response to ferrous sulfate. RBV was calculated by two methods: slope-ratio and ratio of hemoglobin regeneration efficiency, and both yielded RBV of 26 for laver. Amount of available iron from laver estimated from RBV was comparable to many iron-fortified foods.

Ligand selectivity of the peroxisome proliferator-activated receptor alpha.

Peroxisome proliferator-activated receptors (PPAR alpha, beta, and gamma) are nuclear hormone receptors that play critical roles in regulating lipid metabolism. It is well established that PPARs are the targets for the hypolipidemic synthetic compounds known as peroxisome proliferators, and it has been proposed that various long-chain fatty acids and metabolites of arachidonic acid serve as the physiological ligands that activate these receptors in vivo. However, a persistent problem is that reported values of the equilibrium dissociation constants (Kds) of complexes of PPARs with these ligands are in the micromolar range, at least an order of magnitude higher than the physiological concentrations of the ligands. Thus, the identity of the endogenous ligands for PPAR remains unclear. Here we report on a fluorescence-based method for investigating the interactions of PPAR with ligands. It is shown that the synthetic fluorescent long-chain fatty acid trans-parinaric acid binds to PPARalpha with high affinity and can be used as a probe to monitor protein-ligand interactions by the receptor. Measurements of Kds characterizing the interactions of PPARalpha with various ligands revealed that PPARalpha interacts with unsaturated C:18 fatty acids, with arachidonic acid, and with the leukotriene LTB4 with affinities in the nanomolar range. These data demonstrate the utility of the optical method in examining the ligand-selectivity of PPARs, and resolve a long-standing uncertainty in understanding how the activities of these receptors are regulated in vivo.

Iron deficiency and anemia in school children and adolescents.

A survey of iron status of school children and adolescents was carried out in 1990. Subjects were 371 school children (189 males and 182 females) aged 7 to 12.9 years and 352 school teenagers (169 males and 183 females) aged 13 to 19.9 years from Taichung County and Pingtung County. Venous blood was collected and concentrations of hemoglobin, plasma transferrin and plasma ferritin were measured. Diagnosis of anemia was based on FAO/WHO (Food and Agriculture Organization/World Health Organization) criteria of hemoglobin values. Iron deficiency was defined as ferritin levels < 12 micrograms/L. For subjects of primary school ages, the rate of iron deficiency in boys was 2% in Pingtung and 0% in Taichung, and that in girls was 3.33% in Pingtung and 2.17% in Taichung. For teenage subjects, the rate of iron deficiency in males was 1.22% in Pingtung and 0% in Taichung, and that in females was 9.38% in Pingtung and 26.4% in Taichung. For subjects of primary school ages, the anemia rate in boys was 5% in Pingtung and 3.37% in Taichung, and that of girls was 5.56% in Pingtung and 1.09% in Taichung. For teenage subjects, the anemia rate in males was 3.66% in Pingtung and 3.45% in Taichung, and that in females was 8.33% in Pingtung and 5.75% in Taichung. In both areas, iron deficiency was more prevalent in females than in males, and the highest rate occurred in teenage girls. Iron deficiency was not the major underlying cause of anemia and iron deficiency anemia was relatively rare (< 2%). Teenage girls are identified as a group at risk of iron deficiency and anemia.

PIP: During April-May 1990 in Taiwan, health workers collected 10 ml venous blood samples from 371 school children 7-12.9 years old and from 352 adolescent students 13-19.9 years old attending primary, junior high, and senior high schools in Pingtung County and Taichung County. The researcher aimed to determine the iron status and prevalence of anemia in these children. Ferritin levels of less than 12 mcg/l defined iron deficiency. In both counties, girls were more likely to suffer from iron deficiency than boys. Teenage girls had the highest rate of iron deficiency (9.38% vs. 1.22-2% in Pingtung and 26.4% vs. 0-2.17% in Taichung). Among school children 7-12.9 years old in Pingtung, 2% of the boys in Pingtung and 3.33% of girls had iron deficiency. In Taichung, 0% of boys and 2.17% of girls had iron deficiency. Among the teenagers in Pingtung, 1.22% of the boys and 9.38% of girls had iron deficiency. These rates in Taichung were 0% and 26.4%, respectively. Less than 2% of all children had iron deficiency anemia. Among school children 7-12.9 years old in Pingtung, the anemia rate was 5% for boys and 5.56% for girls. In Taichung, 3.37% of the boys and 1.09% of girls had anemia. Among teenagers 13-19.9 years old in Pingtung, 3.66% of boys and 8.33% of girls had anemia. In Taichung, the anemia rate was 3.45% and 5.75%, respectively. These findings show that teenage girls are more likely to have iron deficiency than males. Thus, health officials need to develop an effective nutritional intervention and health care for youths to improve their iron status.

A vegetarian diet rich in soybean products compromises iron status in young students.

The iron status of young Chinese Buddhist vegetarians (23 men and 32 women) and nonvegetarian students (20 men and 39 women from a medical college) was investigated by dietary assessment of iron intake and hematological measurement of biochemical indices including hemoglobin, plasma iron, transferrin, transferrin saturation and plasma ferritin. A characteristic of the vegetarian diet in this study was the replacement of meat by soybean products. Results of the dietary assessment showed that the average iron density of the diets ranged from 1.9 to 2.2 mg/MJ, with no difference between the vegetarian and nonvegetarian diets. Daily iron intake was similar in both vegetarian and nonvegetarian men. However, iron intake was significantly higher in female vegetarians than nonvegetarians, averaging 104 and 78% of the RDA, respectively. Results of blood analysis showed that, for both sexes, the median plasma ferritin concentration of the vegetarians (male 47 micrograms/L and female 12 micrograms/L) was about half the level of the nonvegetarians (male 91 micrograms/L and female 27 micrograms/L). Occurrence and risk of iron deficiency are more prevalent in vegetarians. Correlation between plasma ferritin concentration and years of vegetarian practice in vegetarian men was marginally significant (r = -0.38, P = 0.077). We conclude that a vegetarian diet that is rich in soybean products and restricted in animal foods is limited in bioavailable iron and is not adequate for maintaining iron balance in men and women.

Eating more and enjoying it less: U.S. prison diets for women.

A study of weight gain and dietary adequacy among female prisoners was conducted by studying inmate weight changes, nutritional values of prison diets and consumption patterns in a jail cafeteria. Inmates were found to incur significant weight gains (Mean = 14 lbs.); their diets were inadequate nutritively, and were consumed in such a way as to exacerbate the inadequacies. The authors conclude that some of these problems could be ameliorated by changing ingredients, preparation, and the role of food in the prisoner's life, although for certain categories of prisoners with specific health conditions (e.g., pregnancy), adequate diets will require major adjustments in jail and prison food management.

Sexism and medical care in a jail setting.

As part of a study on health conditions in women's prisons, comparisons were made of outcomes of clinic visits by male and female prisoners in New York City jails on Rikers' Island. Despite a basic similarity in health problems, significant differences were found between the sexes in terms of number of clinicians with whom they had interaction, access to a physician, and access to treatment of any sort. Men were four times as likely to be seen by a physician and twice as likely to receive treatment. A general pattern of sex bias was determined to exist. Staffing patterns, clinic access and diagnostic bias are examined as possible explanations for the differences in care.