Book
Regulation of bone quality and calcium absorption in obesity and during caloric restriction in women
01 Jan 2011
Abstract
Weight loss (WL) is associated with loss of bone loss due to several factors such as decrease in intake of calcium, true fractional calcium absorption (TFCA), serum insulin like growth factor-1 (IGF-1), reduced weight bearing. The aim in this dissertation was to understand whether a higher intake of dietary protein and vitamin D can attenuate bone loss during caloric restriction (CR), and addresses bone quality and altered hormonal milieu in obesity. In the first trial, our goal was to examine how bone responds to CR during a 1 year randomized trial using 2 levels of protein intake with controlled calcium intake of 1.2 g/d in both groups. Forty seven women were randomized to either a normal (18%) or higher (24%) protein intake for 1 year. Our results showed greater loss of BMD at certain sites and lower IGF-1 in the NP compared to HP diet (p <0.05). The second trial hypothesized that a higher compared to normal vitamin D supplementation will attenuate the decrease in TFCA associated with CR. Eighty four women were supplemented with either 2500 IU/d or 400 IU/d of vitamin D sub(3) for 6 weeks during WL or weight maintenance (WM). TFCA increased with 2500 IU/d D supplementation in the WM-D group by 3.7% (p <0.05) however did not attenuate the decrease in TFCA associated with CR, with the greatest increase in 25 hydroxy vitamin D (25OHD) in the WL-D group. These findings suggest that vitamin D supplementation does not attenuate the decrease in TFCA associated with CR. The cross sectional study in this dissertation aimed at evaluating bone quality in obesity using peripheral quantitative computed tomography (pQCT). Our results in 211 women showed that obesity is associated with higher trabecular bone and lower cortical BMD. A separate case control clinical study in 111 women shows that high serum PTH in obesity is also associated with higher monocyte chemoattractant protein (MCP-1). This unique effect of parathyroid hormone (PTH) on MCP-1 is independent of the level of adiposity. Together these studies evaluate nutrient supplementation in attenuating bone loss during CR and help better understand bone quality and higher serum PTH in obesity.
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Details
- Title
- Regulation of bone quality and calcium absorption in obesity and during caloric restriction in women
- Creators
- Deeptha Sukumar
- Resource Type
- Book
- Language
- English
- Academic Unit
- Nutrition Sciences
- Identifiers
- 9781267166456; 1267166452; 991019231747704721