Roles of vitamin D, n-3 polyunsaturated fatty acid, and soy isoflavones in bone health.
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Bone and Bones↗
Biomedical subjects
Laura Harkness
Publications and source records attributed to Laura Harkness.
Low levels of 25-hydroxy vitamin D are associated with elevated parathyroid hormone in healthy adolescent females.
This study aimed to investigate the relationship between 25-hydroxyvitamin D [25(OH)D)] and parathyroid hormone (PTH) levels in adolescent females residing in a northern climate. Concern regarding vitamin D status in this population is due to limited sunlight exposure in northern latitudes, decreased outdoor recreational activities, as well as decreased conversion in black girls from increased skin pigmentation. In this cross-sectional analysis, serum samples were assayed for 25(OH)D using competitive protein binding (CPB) assay and PTH with immuno-radiometric (RIA) procedures. Four hundred postmenarcheal females (12-18 years) residing in northeastern Ohio were recruited. Subjects were excluded if they had a history of bone, kidney, or liver disease, or used medications that affect bone. The primary goal was to determine serum 25(OH)D concentrations in relation to circulating PTH levels in a population of adolescent girls. The Spearman correlation test was used to compare PTH and 25(OH)D. Fit multiple split models were run to determine change in slope of the regression line when 25(OH)D and PTH were plotted. Analysis of variance was determined using modeled means with differences by race and season in the final model. Unadjusted mean serum 25(OH)D and PTH levels were 55.0+/-30.4 nmol/l and 39.4+/-20.6 ng/l, respectively. Blacks had lower 25(OH)D and higher PTH compared with non-blacks (P<0.0001), especially during the winter months. Decreasing 25(OH)D was inversely correlated with PTH (r=-0.314) (P<0.0001), and at concentrations of 25(OH)D < or =90 nmol/l, an increase in PTH was observed. Adolescents are at risk for decreased serum 25(OH)D concentrations, especially black girls. We found that the widely used cutoff for vitamin D deficiency is associated with increasing PTH levels and is below the inflection point for a change in the slope of the regression line. Our results support the need for further research to establish optimal vitamin D status in adolescent girls.
Adolescent↗
The history of enteral nutrition therapy: from raw eggs and nasal tubes to purified amino acids and early postoperative jejunal delivery.
Although enteral feeding therapy has existed since ancient Egypt, most of the major advances in enteral feeding techniques and formulas took place during the 20th century, including postpyloric tube placement in 1910; continuous and controlled delivery of liquid nutrition in 1916; feeding during surgery and modification of macronutrients in 1918; feeding via a pump in 1930; recognition of the importance of nutrition therapy during injury recovery and the addition of micronutrients and early postoperative feeding in 1940; the introduction of commercial products during the 1950s with chemically defined formulas following a decade later; and the development of modern formulas during the 1970s. The purpose of this review is to provide a historical account of enteral nutrition, including modes and routes of delivery, types of diet, and refinements in delivery techniques and formulas and to offer the history of the therapy as a resource for developing and improving enteral feeding techniques and therapies and implementing optimal patient care strategies.
Critical Care↗
Soy and bone. Where do we stand?
Interest in the use of plant estrogens (phytoestrogens) to attenuate postmenopausal bone loss has increased during the past 10 years as healthcare consumers, practitioners, and scientists have searched for alternative treatments to the use of hormone replacement therapy. Promising research has emerged regarding the potential benefit of increased consumption of phytoestrogens, primarily from dietary soy products. Dietary phytoestrogens, primarily isoflavones found in soy foods, may alter bone turnover in postmenopausal women by decreasing bone resorption and increasing bone formation.
Animals↗