Gluconeogenesis and energy expenditure after a high-protein, carbohydrate-free diet  

Oleh:

Veldhorst, Margriet A.B. ; Westerterp-Plantenga, Margriet S. ; Westerterp, Klaas R.

Jenis: Article from Journal - ilmiah internasional
Dalam koleksi: The American Journal of Clinical Nutrition vol. 90 no. 03 (Sep. 2009), page 519-526.
Topik: Gluconeogenesis; high-protein; carbohydrate-free diet; energy expenditure (EE)

Ketersediaan

Perpustakaan FK Nomor Panggil: A07.K.2009.03 Non-tandon: 1 (dapat dipinjam: 0) Tandon: tidak ada

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Isi artikel

Background: High-protein diets have been shown to increase energy expenditure (EE). Objective: The objective was to study whether a high-protein, carbohydrate-free diet (H diet) increases gluconeogenesis and whether this can explain the increase in EE. Design: Ten healthy men with a mean (±SEM) body mass index (in kg/m2) of 23.0 ± 0.8 and age of 23 ± 1 y received an isoenergetic H diet (H condition; 30%, 0%, and 70% of energy from protein, carbohydrate, and fat, respectively) or a normal-protein diet (N condition; 12%, 55%, and 33% of energy from protein, carbohydrate, and fat, respectively) for 1.5 d according to a randomized crossover design, and EE was measured in a respiration chamber. Endogenous glucose production (EGP) and fractional gluconeogenesis were measured via infusion of [6,6-2H2]glucose and ingestion of 2H2O; absolute gluconeogenesis was calculated by multiplying fractional gluconeogenesis by EGP. Body glycogen stores were lowered at the start of the intervention with an exhaustive glycogen-lowering exercise test. Results: EGP was lower in the H condition than in the N condition (181 ± 9 compared with 226 ± 9 g/d; P < 0.001), whereas fractional gluconeogenesis was higher (0.95 ± 0.04 compared with 0.64 ± 0.03; P < 0.001) and absolute gluconeogenesis tended to be higher (171 ± 10 compared with 145 ± 10 g/d; P = 0.06) in the H condition than in the N condition. EE (resting metabolic rate) was greater in the H condition than in the N condition (8.46 ± 0.23 compared with 8.12 ± 0.31 MJ/d; P < 0.05). The increase in EE was a function of the increase in gluconeogenesis ({Delta}EE = 0.007 x {Delta}gluconeogenesis – 0.038; r = 0.70, R2 = 0.49, P < 0.05). The contribution of {Delta}gluconeogenesis to {Delta}EE was 42%; the energy cost of gluconeogenesis was 33% (95% CI: 16%, 50%). Conclusions: Forty-two percent of the increase in energy expenditure after the H diet was explained by the increase in gluconeogenesis. The cost of gluconeogenesis was 33% of the energy content of the produced glucose.

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