Sex, diet density and feeding centre gene expression

## Background ## Research into energy balance and growth has infrequently considered genetic sex, yet there is sexual dimorphism for growth across the animal kingdom. We test the hypothesis that sexual dimorphism for growth and body weight in birds is potentially dependent on hypothalamic agouti-related peptide (AGRP) expression, since previous research indicates hypothalamic AGRP expression is correlated with growth potential. ## Conclusion ## Expression of orexigenic peptides in the avian hypothalamus are correlated with sex differences in growth and body weight. The differences in gene expression between sexes provides further evidence of AGRP expression being correlated to growth potential. Results also suggest that gut-fill alone does not reduce orexigenic gene expression

Relative validation of a short food frequency questionnaire to assess calcium intake in older adults

Objective: To develop and validate a food frequency questionnaire (FFQ) for estimating calcium intake in community-dwelling older adults using a food record as the reference method.\ud \ud Method: A validation study involving 102 subjects (67 females) aged 65 years and residing independently in Adelaide, Australia, between 2002–06 was performed. Estimates of calcium intake over the last year were calculated from two versions (35 and 15 items) of the FFQ and compared with average intake from four days of non-consecutive food records (4DFR).\ud \ud Results: Mean calcium intake from the 4DFR was 987 mg/day (95% CI 922–1051). The 35 and 15-item questionnaires gave mean intakes of 992 mg/day (95% CI 913–1,071) and 1017 mg/day (95% CI 927–1,106) respectively. Mean difference (95% limits of agreement) between the food record and the 35 and 15-item questionnaires was 5 mg (-739 – 729) and 28 mg (-936 – 879) respectively. The 15-item questionnaire demonstrated 82% sensitivity for classifying subjects with calcium intake below the estimated average requirement (EAR, 840 mg for males 51–70 years; 1,100 mg for females >51 years and males >70 years of age) and 46% specificity for classifying subjects with intake above the EAR.\ud \ud Conclusion: The FFQ evaluated as part of this study is one of very few that has been tested across both genders and in older adults specifically. The 15-item version has demonstrated a level of sensitivity and specificity comparable with other FFQs for evaluating calcium intake.\ud \ud Implications: The 15-item FFQ can be confidently used for measuring group mean calcium intake in older Australians or as a screening tool to allow health professionals to identify those who are most at risk of inadequate dietary calcium intake

Diet Modulates the Effects of Genetic Variants on the Vitamin D Metabolic Pathway and Bone Mineral Density in Mexican Postmenopausal Women

BackgroundMacro- and micronutrients, such as proteins, vitamin D, and calcium (Ca), are important dietary factors that can modify bone mineral density (BMD). Genetic factors can interact with diet, affecting an individual's predisposition to osteoporosis.ObjectivesThis study aimed to evaluate the associations between macro- and micronutrient intakes and BMD in Mexican postmenopausal women, and their interactions with genetic polymorphisms involved in the vitamin D metabolic pathway.MethodsWe analyzed data from 317 postmenopausal women from the Health Workers Cohort Study, a longitudinal cohort studied in Cuernavaca, Mexico. Postmenopausal women participated in 2 data collection waves (2004-2006 and 2010-2011), with a mean time of 6.4 years. Dietary intake was assessed with a semi-quantitative FFQ. BMD (femoral neck, hip, and lumbar spine) was measured by DXA. Hybrid mixed-effects regression models were used to assess the associations of dietary macro- and micronutrients on BMD, after adjusting for confounding factors and for diet and single nucleotide polymorphism interactions.ResultsAt baseline, the median age was 57 years (IQR, 50-64). Mean femoral neck, hip, and lumbar spine BMDs decreased over time. We observed statistically significant longitudinal associations for diet (Ca, vitamin D, magnesium, phosphorus, and protein intake) and BMD. Increases of vitamin D, Ca, and protein intakes by 1 SD were associated with mean increases in the femoral neck BMD (0.083 SD, 0.064 SD, and 0.130 SD, respectively). Multiple significant interactions were identified between several loci (CYP2R1, CYP24A1, CYP27B1, VDR, and DHCR7/NADSYN1) and diet for BMDs (femoral neck, hip, and lumbar spine), mainly for protein intake.ConclusionsOur data support associations of vitamin D, Ca, protein, phosphorous, and magnesium consumption with BMD in Mexican postmenopausal women and suggest possible gene-diet interactions. These results could facilitate future personalized nutrition recommendations to help prevent low BMD