Impact of dietary magnesium upon insulin sensitivity, vascular function, and metabolic complications during development of type 2 diabetes

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Title Impact of dietary magnesium upon insulin sensitivity, vascular function, and metabolic complications during development of type 2 diabetes
Publication Type thesis
School or College College of Health
Department Nutrition & Integrative Physiology
Author Smith, Alexander James Barker
Date 2017
Description Background: Epidemiological data associates low magnesium (Mg) intake with greater risk of metabolic syndrome/diabetes, and Mg status is often compromised in diabetic patients. It remains unclear whether low Mg consumption may exacerbate the metabolic disruptions that occur during diabetes. Objective: We hypothesized low dietary Mg during the development of diabetes would alter metabolic rate, and worsen glucose tolerance/insulin sensitivity. Methods: Three cohorts (n = 8 each) of 8-week-old TallyHo (TH) mice that develop Type 2 Diabetes by 16 weeks of age were fed special diets for 8 weeks. Group 1: TH + Low Mg diet (L-Mg, 100mg Mg Oxide/kg chow). Group 2: TH + Standard Mg diet (S-Mg, 500mg Mg Oxide/kg chow). Group 3: TH + High Mg diet (H-Mg, 1000mg Mg Bisglycinate/kg chow). Age-matched male C57BL/6J mice fed standard diets served as controls (Con, n = 8, 500mg Mg Oxide/kg chow). Results: Energy expenditure was lowest (p < 0.05) in L-Mg vs. all other groups. Insulin tolerance test (AUC, glucose mg/dL), indicated insulin resistance (p < 0.05) in L-Mg (12394 ± 2344) vs. Con (3866 ± 2344), and a trend (p = 0.052) indicating greater insulin resistance in S-Mg (10429 ± 2193) vs. Con. However, insulin tolerance was normalized in H-Mg (7838 ± 2344) vs. Con. QUICKI index indicated that all groups were insulin resistant (p < 0.05) compared to Con (0.585 ± 0.14). However, L-Mg (0.403 ± 0.15) had greater (p < 0.05) insulin resistance than S-Mg (0.462 ± 0.17) and H-Mg (0.454 ± 0.15). Insulin stimulated phosphorylation of hepatic insulin receptor was similar among all groups, whereas Akt phosphorylation was reduced (p < 0.05) in all diabetic mice regardless of Mg intake. Conclusions: Low dietary Mg intake reduces oxygen consumption and energy expenditure, and worsens insulin sensitivity in diabetic mice. Supplemental Mg can partially reduce fasting glucose and improve insulin tolerance, but could not be attributed to an improvement in hepatic insulin signaling.
Type Text
Publisher University of Utah
Subject Endocrinology; Nutrition; Physiology; Epidemiology
Dissertation Name Master of Science
Language eng
Rights Management (c) Alexander James Barker Smith
Format application/pdf
Format Medium application/pdf
ARK ark:/87278/s61g548s
Setname ir_etd
ID 1431828
Reference URL https://collections.lib.utah.edu/ark:/87278/s61g548s
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