Amino acid intakes are associated with bone mineral density and prevalence of low bone mass in women: evidence from discordant monozygotic twins

Although a higher protein intake, particularly from vegetable sources, has been shown to be associated with higher bone mineral density (BMD) the relative impact of specific amino acids (AA) on BMD and risk of osteoporosis remains to be determined. Mechanistic research suggests that a number of specific AA, including five non-essential AA, alanine, arginine, glutamic acid, glycine and proline, may play a role in bone health, principally through improved production of insulin and insulin-like growth factor 1 and the synthesis of collagen and muscle protein. However to date, no previous studies have examined the associations between habitual intake of AA and direct measures of BMD and prevalence of osteoporosis or osteopenia and no studies have examined this relationship in discordant identical twin-pairs. In these analyses of female monozygotic twin-pairs discordant for AA intake (n=135), twins with higher intakes of alanine and glycine had significantly higher BMD at the spine than their co-twins with within-pair differences in spine-BMD of 0.012 g/cm2 (SE 0.01 P=0.039) and 0.014g/cm2 (SE 0.01 P=0.026) respectively. Furthermore, in cross-sectional multivariable analyses of 3160 females aged 18-79y, a higher intake of total protein was significantly associated with higher DXA-measured BMD at the spine (Q4-Q1 0.017g/cm2 SE 0.01 P=0.035) and forearm (Q4-Q1 0.010g/cm2 SE 0.003 P=0.002). Intake of six AA (alanine, arginine, glutamic acid, leucine, lysine and proline) were associated with higher BMD at the spine and forearm with the strongest association observed for leucine (Q4-Q1 0.024g/cm2 SE 0.01 P=0.007). When intakes were stratified by protein source, vegetable or animal, prevalence of osteoporosis or osteopenia was 13-19% lower comparing extreme quartiles of vegetable intake for five AA (not glutamic acid or proline). These data provide evidence to suggest that intake of protein and several AA, including alanine and glycine, may be beneficial for bone health, independent of genetic background

Tea and coffee consumption in relation to vitamin D and calcium levels in Saudi adolescents

Background Coffee and tea consumption was hypothesized to interact with variants of vitamin D-receptor polymorphisms, but limited evidence exists. Here we determine for the first time whether increased coffee and tea consumption affects circulating levels of 25-hydroxyvitamin D in a cohort of Saudi adolescents. Methods A total of 330 randomly selected Saudi adolescents were included. Anthropometrics were recorded and fasting blood samples were analyzed for routine analysis of fasting glucose, lipid levels, calcium, albumin and phosphorous. Frequency of coffee and tea intake was noted. 25-hydroxyvitamin D levels were measured using enzyme-linked immunosorbent assays. Results Improved lipid profiles were observed in both boys and girls, as demonstrated by increased levels of HDL-cholesterol, even after controlling for age and BMI, among those consuming 9–12 cups of coffee/week. Vitamin D levels were significantly highest among those consuming 9–12 cups of tea/week in all subjects (p-value 0.009) independent of age, gender, BMI, physical activity and sun exposure. Conclusion This study suggests a link between tea consumption and vitamin D levels in a cohort of Saudi adolescents, independent of age, BMI, gender, physical activity and sun exposure. These findings should be confirmed prospectively

Bone Health Nutrition Issues in Aging

Bone health is an important issue in aging. Calcium and vitamin D currently have the most focus in published research on nutrition and bone health in aging, although evidence from published research is not conclusive. A systematic review was conducted to determine the impact of dietary and supplemental interventions focused on calcium and vitamin D over the past 10 years. Using key words to search, and search limits (aging population, English), 62 papers were found related to diet, nutrition, and bone; and 157 were found related to calcium and bone. Our review found a positive effect on bone health for supplements; food-based interventions; and educational strategies. Although there may be a publishing bias related to non-significant findings not being published, our results suggest the effectiveness of food based and educational interventions with less economic impact to the individual, as well as less risk of physiological side effects occurring

Estrogen Receptor α36 Mediates a Bone-Sparing Effect of 17β-Estrodiol in Postmenopausal Women

Recently, a membrane-based estrogen receptor (ER), ER-α36, was identified and cloned that transduces membrane-initiated estrogen signaling such as activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway. Here we show that the postmenopausal level of estradiol (E2) induces mitogenic, antiapoptotic, and antiosteogenic effects and proapoptotic effects in postmenopausal osteoblasts and osteoclasts with high levels of ER-α36 expression, respectively. We also found that ER-α36 mediated the effects of postmenopausal-level E2 on proliferation, apoptosis, and differentiation of osteoblasts through transient activation of the MAPK/ERK pathway, whereas ER-α36-mediated postmenopausal-level E2 induces apoptosis of osteoclasts through prolonged activation of the MAPK/ERK pathway with the involvement of reactive oxygen species. We also show that the levels of ER-α36 expression in bone are positively associated with bone mineral density but negatively associated with bone biochemical markers in postmenopausal women. Thus the higher levels of ER-α36 expression are required for preserving bone mass in postmenopausal and menopausal women who become osteoporotic if ER-α36-mediated activities are dysregulated. © 2011 American Society for Bone and Mineral Research

Limited compensation at the following meal for protein and energy intake at a lunch meal in healthy free-living older adults.

Various interventions have previously been found to increase protein intakes in older adults, but in free-living individuals, compensation for increased intakes at one meal may easily negate these effects resulting in limited long term benefit. This study investigated the impact of adding sauce to an older person's lunch meal on intakes at that meal, at the following meal and overall (lunch + evening meal). Using a repeated measures design, 52 participants consumed both a lunch meal with sauce and the same lunch meal without sauce on two separate occasions, and intake at this meal and at the following meal were measured. In all participants analysed together, the addition of sauce resulted in increased protein intakes at the lunch meal. Individual differences were also found, where for some individuals (n = 26), the addition of sauce resulted in significantly higher protein and energy intakes at the lunch meal (12.3 g protein, 381 kJ) and overall (11 g protein, 420 kJ), compared to the no-sauce condition, while for some individuals (n = 19), the sauce manipulation resulted in lower protein and energy intakes (lunch: 7 g protein, 297 kJ; overall: 7 g protein, 350 kJ). Compensation for earlier intakes was low (0-17%) for both groups. These findings demonstrate the possible value of adding sauce to an older person's meal for increasing intakes, and demonstrate a need for attention to individual differences. This study also confirms previous findings of limited compensation in older adults, but extends earlier studies to demonstrate limited compensation for the protein consumed in a complete meal in healthy older adults

Genetic polymorphisms are associated with serum levels of sex hormone binding globulin in postmenopausal women

<p>Abstract</p> <p>Background</p> <p>Estrogen activity plays a critical role in bone homeostasis. The serum levels of sex hormone binding globulin (SHBG) influence free estrogen levels and activity on target tissues. The objective of this study was to analyze the influence of common polymorphisms of the <it>SHBG </it>gene on serum SHBG, bone mineral density (BMD), and osteoporotic fractures.</p> <p>Methods</p> <p>Four biallelic polymorphisms of the <it>SHBG </it>gene were studied by means of Taqman assays in 753 postmenopausal women. BMD was measured by DXA and serum SHBG was measured by ELISA.</p> <p>Results</p> <p>Age, body weight, and two polymorphisms of the <it>SHBG </it>gene (rs6257 and rs1799941 [A/G]) were significantly associated with serum SHBG in unadjusted and age- and weight-adjusted models. Alleles at the rs1799941 locus showed the strongest association with serum SHBG (p = 0.0004). The difference in SHBG levels between women with AA and GG genotypes at the rs1799941 locus was 39%. There were no significant differences in BMD across SHBG genotypes. The genotypes showed similar frequency distributions in control women and women with vertebral or hip fractures.</p> <p>Conclusion</p> <p>Some common genetic variants of the <it>SHBG </it>gene, and particularly an A/G polymorphism situated in the 5' region, influence serum SHBG levels. However, a significant association with BMD or osteoporotic fractures has not been demonstrated.</p

Korean Guidelines for Postpolypectomy Colonoscopy Surveillance

Postpolypectomy surveillance has become a major indication for colonoscopy as a result of increased use of screening colonoscopy in Korea. In this report, a careful analytic approach was used to address all available evidences to delineate the predictors for advanced neoplasia at surveillance colonoscopy and we elucidated the high risk findings of the index colonoscopy as follows: 3 or more adenomas, any adenoma larger than 10 mm, any tubulovillous or villous adenoma, any adenoma with high-grade dysplasia, and any serrated polyps larger than 10 mm. Surveillance colonoscopy should be performed five years after the index colonoscopy for those without any high-risk findings and three years after the index colonoscopy for those with one or more high risk findings. However, the surveillance interval can be shortened considering the quality of the index colonoscopy, the completeness of polypectomy, the patient's general condition, and family and medical history