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Whole Body Protein Turnover in Overweight/Obese Adults in Response to Whole Grain and Refined Grain Diets – A Randomized Control Trial
Author(s) -
Kirwan John P,
Ross Alastair B.,
Kullman Emily L,
Malin Steve K,
Scelsi Amanda,
Kochhar Sunil,
Godin JeanPhilippe
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.909.4
Subject(s) - overweight , crossover study , protein turnover , medicine , endocrinology , obesity , calorie , protein metabolism , zoology , chemistry , metabolism , biology , placebo , biochemistry , protein biosynthesis , alternative medicine , pathology
Data from several intervention studies suggest that whole grains (WG) lead to increased fat loss and enhanced metabolic function compared to control diets. Abnormalities in energy balance and protein metabolism, including protein flux, protein synthesis and protein breakdown, are part of the obesity phenotype and may be amenable to change by altering nutrient intake using a WG enriched diet. We hypothesized that a whole grain enriched diet would alter protein metabolism and total energy expenditure (TEE), and thus contribute to increased muscle mass and a decrease in fat mass. We performed a double‐blind crossover diet intervention study to examine the effects of a WG‐based diet on protein kinetics, TEE and body composition, compared to a calorie matched control diet (refined grain (RG)). Complete diets were provided to subjects, based on nutritional guidelines for fat, protein (1.05 g/kg/day) and carbohydrate, with either WG (50g/1000 kcal) or equivalent RG. Fourteen overweight/obese (BMI 32.9 ± 4.5 kg/m 2 ) adults (age 39 ± 7 years) participated in the trial. Each diet was provided for 8 weeks, with a 10‐week washout between diet arms. TEE was assessed by doubly labeled water ( 2 H 2 18 O), whole body protein turnover was assessed using a stable isotope approach (oral dose of 15 N‐Glycine), and body composition was determined from DEXA measures. After 8 weeks of WG and RG diet, changes in body weight and fat free mass were similar for both diets. Likewise, TEE did not differ between the diets (~2147 ± 291 kcal/day). Protein synthesis was 3.7 ± 0.5 g protein/kg/day for both diets (P>0.05), while protein breakdown was 4.7 ± 0.5 and 4.9 ± 0.4 g protein/kg/day for WG and RG diets, respectively. For protein balance the values were −1.03 ± 0.05 and −1.1 ± 0.1 g, protein/kg/day for WG and RG diets (P>0.05), respectively. Rates of protein synthesis, breakdown and nitrogen balance were higher after the WG diet when expressed relative to FFM, but protein turnover was similar for effects between diets. We conclude that 8 weeks on a WG diet does not produce significantly different changes in body composition, TEE, or whole body protein metabolism, when compared to a calorie matched control diet. Support or Funding Information Investigator‐initiated grant, Nestlé; NIH UL1RR024989 and T32 DK007319.