Description
TitleThe influence of dietary fat and intestinal pH on calcium bioaccessibility
Date Created2016
Other Date2016-10 (degree)
Extent1 online resource (vi, 54 p. : ill.)
DescriptionHuman studies measuring true fractional calcium absorption have shown that dietary fat is a significant predictor of calcium absorption. In murine models, dietary fat also increases calcium absorption, but whether there is a differential effect with the type of fatty acid (FA) on intestinal calcium absorption is less clear. Compared to monounsaturated FAs (MUFAs), saturated FAs (SFAs) decrease lipid membrane fluidity and have a greater intestinal transit time, potentially prolonging their interaction with calcium in the gut. In addition, SFAs bind to calcium forming insoluble soaps, increasing fecal fat excretion, and reducing calcium availability for absorption. In addition, luminal factors such as a higher pH in the GI tract could influence calcium absorption such as with certain medications or achlorhydria. The TNO gastrointestinal model (TIM-1) replicates the physiological activities occurring in the lumen of the stomach, duodenum, jejunum, and ileum and is used to study biological events preceding nutrient absorption (i.e., bioaccessibility). In this study, we examined two high fat formulas (SFA or MUFA enriched) compared to low fat and controlled for calcium (500 mg) and other micronutrients during a 5-hr experiment. Calcium bioaccessibility (CaB) was greater for the high compared to low fat test meal in the jejunum (p = 0.001). In addition, CaB with the SFA alone was higher than either LFD or MUFA (p < 0.01). However, there was no interaction between diet and CaB in the ileum or ileal efflux. During high gastrointestinal pH, CaB was similar between diets in the jejunum and ileum, and there was a trend for increasing non-bioaccessible calcium over time (p = 0.058). Furthermore, CaB was 90% (p = 0.003), 91% (p = 0.036), and 94% (p = 0.001) lower in the jejunum, ileum, and ileal efflux, respectively at high pH compared to normal gastrointestinal conditions. These findings suggest a dramatically lower CaB under high pH conditions, having implications for a wide range of patients with gastrointestinal disorders. In addition, the higher Ca absorption associated with a high fat diet found previously, may be partially explained by an increased CaB.
NoteM.S.
NoteIncludes bibliographical references
Noteby Elhaam Bandali
Genretheses, ETD graduate
Languageeng
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.