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Effects of whole and refined grains in a weight-loss diet on markers of metabolic syndrome in individuals with increased waist circumference: a randomized controlled-feeding trial.
Harris Jackson, K, West, SG, Vanden Heuvel, JP, Jonnalagadda, SS, Ross, AB, Hill, AM, Grieger, JA, Lemieux, SK, Kris-Etherton, PM
The American journal of clinical nutrition. 2014;(2):577-86
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Abstract
BACKGROUND Higher whole-grain (WG) intake is associated with a lower prevalence of metabolic syndrome (MetS); however, there is inconsistent clinical evidence with regard to the benefit of WGs compared with refined grains (RGs) on MetS. OBJECTIVE We hypothesized that consuming WGs in the place of RGs would improve MetS criteria in individuals with or at risk of MetS. DESIGN A randomized, controlled, open-label parallel study was conducted in 50 overweight and obese individuals with increased waist circumference and one or more other MetS criteria. Participants consumed a controlled weight-loss diet containing either WG or RG (control) products for 12 wk. Body composition, MetS criteria and related markers, and plasma alkylresorcinols (compliance marker of WG intake) were measured at baseline and at 6 and 12 wk. A subgroup (n = 28) underwent magnetic resonance imaging to quantify subcutaneous and visceral adipose tissue (AT). RESULTS Baseline variables were not significantly different between groups; however, the RG group tended to have higher triglycerides and lower high-density lipoprotein (HDL) cholesterol (P = 0.06). Alkylresorcinols increased with consumption of the WG diet and did not change with consumption of the RG diet (time × treatment, P < 0.0001), which showed dietary compliance. There were no differences in anthropometric changes between groups; however, weight, body mass index, and percentage of body AT decreased at both 6 and 12 wk (P < 0.05), and reductions in percentage of abdominal AT occurred by 6 wk and did not change between 6 and 12 wk (P = 0.09). Both glucose (P = 0.02) and HDL cholesterol (P = 0.04) were lower with the consumption of the WG compared with the RG diet. However, when noncompliant individuals (n = 3) were removed, the glucose effect was stronger (P = 0.01) and the HDL-cholesterol effect was no longer significant (P = 0.14). CONCLUSIONS Replacing RGs with WGs within a weight-loss diet does not beneficially affect abdominal AT loss and has modest effects on markers of MetS. WGs appear to be effective at normalizing blood glucose concentrations, especially in those individuals with prediabetes.
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Modulation of amino acid metabolic signatures by supplemented isoenergetic diets differing in protein and cereal fiber content.
Hattersley, JG, Pfeiffer, AF, Roden, M, Petzke, KJ, Hoffmann, D, Rudovich, NN, Randeva, HS, Vatish, M, Osterhoff, M, Goegebakan, Ö, et al
The Journal of clinical endocrinology and metabolism. 2014;(12):E2599-609
Abstract
CONTEXT Amino-acid (AA) metabolic signatures differ in insulin-resistant (IR) obese vs normal-weight subjects, improve after weight loss, and seem to predict the risk of type 2 diabetes. It is unknown whether weight-maintaining dietary measures aimed at influencing IR alter AA signatures of high-risk subjects. SETTING AND DESIGN In the randomized controlled Protein, Fiber and Metabolic Syndrome (ProFiMet) trial we investigated effects of four isoenergetic, moderately fat-reduced diets varying in protein and cereal-fiber contents on complete AA metabolic signatures in 76 group-matched overweight or obese high-risk subjects. We analyzed the relation of whole-body and hepatic IR with AA signatures, body fat composition and liver fat, after 0, 6, and 18 weeks of dietary intervention. Discrimination between diets was further enhanced by providing tailored dietary supplements for twice-daily consumption over 18 weeks in all groups. RESULTS Baseline AA, including branched-chain signatures significantly related to IR, liver fat, and visceral fat mass. Isoenergetic variation of protein and cereal-fiber dietary contents, but not fat restriction, significantly influenced IR, whereas the relation of AA with IR changed with all diets. The tryptophan ratio was significantly suppressed in obese vs overweight participants, but increased after 6 weeks of high cereal-fiber intake to a nonobese phenotype. Modeling analyses revealed diet-induced alterations of complex AA profiles to relate to 70% and 62% of changes in whole-body and hepatic IR. CONCLUSIONS We demonstrate that relatively short-term isoenergetic changes in the diet significantly alter the relation of AA signatures with IR, with possible implications on the determination and treatment of diabetes risk.
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Plasma alkylresorcinols reflect important whole-grain components of a healthy Nordic diet.
Magnusdottir, OK, Landberg, R, Gunnarsdottir, I, Cloetens, L, Åkesson, B, Önning, G, Jonsdottir, SE, Rosqvist, F, Schwab, U, Herzig, KH, et al
The Journal of nutrition. 2013;(9):1383-90
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Abstract
Biomarkers of dietary intake can be important tools in nutrition research. Our aim was to assess whether plasma alkylresorcinol (AR) and β-carotene concentrations could be used as dietary biomarkers for whole-grain, fruits and vegetables in a healthy Nordic diet (ND). Participants (n = 166), 30-65 y with a body mass index of 27-40 kg/m(2) and two more features of metabolic syndrome (International Diabetes Federation definition, slightly modified), were recruited through six centers in the Nordic countries and randomly assigned to an ND or control diet for 18 or 24 wk, depending on study center. Plasma AR and β-carotene were analyzed and nutrient intake calculated from 4-d food records. Median fiber intake increased in the ND group from 2.5 g/MJ at baseline to 4.1 g/MJ (P < 0.001) at end point (week 18 or 24), and median (IQR) fasting plasma total AR concentration increased from 73 (88) to 106 (108) nmol/L, or 45%, from baseline to end point (P < 0.001). The AR concentration was significantly higher in the ND group (P < 0.001) than in the control group at end point. β-Carotene intake tended to increase in the ND group (P = 0.07), but the plasma β-carotene concentration did not change significantly throughout the study and did not differ between the groups at follow-up. In conclusion, an ND resulted in higher dietary fiber intake and increased plasma total AR concentration compared with the control diet, showing that the total AR concentration might be a valid biomarker for an ND in which whole-grain wheat and rye are important components. No significant difference in plasma β-carotene concentrations was observed between the ND and control groups, suggesting that β-carotene may not be a sensitive enough biomarker of the ND.