Toronto 3D Knowledge Synthesis and Clinical Trials Unit

Toronto, Canada

Toronto 3D Knowledge Synthesis and Clinical Trials Unit

Toronto, Canada
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Jovanovski E.,St Michaels Hospital | Jovanovski E.,University of Toronto | Li D.,St Michaels Hospital | Li D.,University of Toronto | And 20 more authors.
Medicine (United States) | Year: 2017

Background: Polyunsaturated fats (PUFAs) have been shown to reduce type 2 diabetes (T2DM) risk and improve insulin responsiveness in T2DM subjects, but whether the plant sources of omega-3 PUFA (alpha-linolenic acid [ALA]) have an effect on glycemic control requires further investigation. Methods: The parameters of interest were glycated hemoglobin (HbA1c), fasting blood glucose (FBG), fasting blood insulin (FBI), homeostatic model assessment for insulin resistance (HOMA-IR), fructosamine, and glycated albumin. A comprehensive search was conducted with MEDLINE, Embase, CINAHL, and Cochrane. Eligible studies included randomized controlled trials (RCTs) ≥1 month in duration that compared diets enriched in ALA with usual diets on glycemic parameters. For each study, the risk of bias as well as the study quality was assessed. Using the statistical software RevMan (v5.3), data were pooled using the generic inverse method with random effects model, and final results were expressed as mean differences (MD) with 95% confidence intervals (CI). Heterogeneity was assessed by the Cochran Q statistic and quantified by the I 2 statistic. Results: A total of 8 trials (N = 212) were included in the meta-Analysis. Compared to a control diet, a median dose of 4.4 g/day of ALA intake for a median duration of 3 months did not affect HbA1c (%) (MD = -.01; [95%:-.32,.31], P = .96). A median ALA dose of 5.4 g/day did not lower FBG (MD = .07; [95% CI:-.61,.76], P = .84) or FBI (MD = 7.03, [95% CI:-5.84, 19.89], P = .28). Summary effect estimates were generally compromised by considerable and unexplained heterogeneity (I 2 ≥75%). In the subgroup analysis of continuous predictors, a reduction in HbA1c (%) and FBG (mmol/L) was significantly associated with an increased intake of ALA. Further adjustment for Publication Bias using Duval and Tweedie's trim-And-fill analysis provided an adjusted, significant MD of-.25 (95% CI:-.38,-.12; P <.001) for HbA1c (%). Conclusions: ALA-enriched diets did not affect HbA1c, FBG, or FBI. The scarce number of existing RCTs and the presence of heterogeneity in our meta-Analysis limit the ability to make firm conclusions about ALA in T2DM management. The potential for ALA to have dose-dependent effects warrants further research in this area. Copyright © 2017 the Author(s). Published by Wolters Kluwer Health, Inc.


Kim S.J.,Toronto | De Souza R.J.,Toronto | Choo V.L.,Toronto | Ha V.,Toronto | And 24 more authors.
American Journal of Clinical Nutrition | Year: 2016

Background: Obesity is a risk factor for developing several diseases, and although dietary pulses (nonoil seeds of legumes such as beans, lentils, chickpeas, and dry peas) are well positioned to aid in weight control, the effects of dietary pulses on weight loss are unclear. Objective: We summarized and quantified the effects of dietary pulse consumption on body weight, waist circumference, and body fat by conducting a systematic review and meta-analysis of randomized controlled trials. Design: We searched the databases MEDLINE, Embase, CINAHL, and the Cochrane Library through 11 May 2015 for randomized controlled trials of $3 wk of duration that compared the effects of diets containing whole dietary pulses with those of comparator diets without a dietary pulse intervention. Study quality was assessed by means of the Heyland Methodologic Quality Score, and risk of bias was assessed with the Cochrane Risk of Bias tool. Data were pooled with the use of generic inverse-variance random-effects models. Results: Findings from 21 trials (n = 940 participants) were included in the meta-analysis. The pooled analysis showed an overall significant weight reduction of 20.34 kg (95% CI: 20.63, 20.04 kg; P = 0.03) in diets containing dietary pulses (median intake of 132 g/d or w1 serving/d) compared with diets without a dietary pulse intervention over a median duration of 6 wk. Significant weight loss was observed in matched negative-energy-balance (weight loss) diets (P = 0.02) and in neutral-energy-balance (weightmaintaining) diets (P = 0.03), and there was low evidence of between-study heterogeneity. Findings from 6 included trials also suggested that dietary pulse consumption may reduce body fat percentage. Conclusions: The inclusion of dietary pulses in a diet may be a beneficial weight-loss strategy because it leads to a modest weight-loss effect even when diets are not intended to be calorically restricted. Future studies are needed to determine the effects of dietary pulses on long-term weight-loss sustainability. This protocol was registered at clinicaltrials.gov as NCT01594567.


Ha V.,Knowledge Factor | Ha V.,University of Toronto | Jayalath V.H.,Knowledge Factor | Jayalath V.H.,University of Toronto | And 8 more authors.
Current Hypertension Reports | Year: 2013

Excessive fructose intake from high-fructose corn syrup (HFCS) and sucrose has been implicated as a driving force behind the increasing prevalence of obesity and its downstream cardiometabolic complications including hypertension, gout, dyslidpidemia, metabolic syndrome, diabetes, and non-alcoholic fatty liver disease (NAFLD). Most of the evidence to support these relationships draws heavily on ecological studies, animal models, and select human trials of fructose overfeeding. There are a number of biological mechanisms derived from animal models to explain these relationships, including increases in de novo lipogenesis and uric acid-mediated hypertension. Differences between animal and human physiology, along with the supraphysiologic level at which fructose is fed in these models, limit their translation to humans. Although higher level evidence from large prospective cohorts studies has shown significant positive associations comparing the highest with the lowest levels of intake of sugar-sweetened beverages (SSBs), these associations do not hold true at moderate levels of intake or when modeling total sugars and are subject to collinearity effects from related dietary and lifestyle factors. The highest level of evidence from controlled feeding trials has shown a lack of cardiometabolic harm of fructose and SSBs under energy-matched conditions at moderate levels of intake. It is only when fructose-containing sugars or SSBs are consumed at high doses or supplement diets with excess energy that a consistent signal for harm is seen. The available evidence suggests that confounding by excess energy is an important consideration in assessing the role of fructose-containing sugars and SSBs in the epidemics of hypertension and other cardiometabolic diseases. © 2013 Springer Science+Business Media New York.

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