Food sources of fructose-containing sugars and glycaemic control: systematic review and meta-analysis of controlled intervention studies

Abstract

ObjectiveTo assess the effect of different food sources of fructose-containing sugars on glycaemic control at different levels of energy control.DesignSystematic review and meta-analysis of controlled intervention studies.Data sourcesMedine, Embase, and the Cochrane Library up to 25 April 2018.Eligibility criteria for selecting studiesControlled intervention studies of at least seven days’ duration and assessing the effect of different food sources of fructose-containing sugars on glycaemic control in people with and without diabetes were included. Four study designs were prespecified on the basis of energy control: substitution studies (sugars in energy matched comparisons with other macronutrients), addition studies (excess energy from sugars added to diets), subtraction studies (energy from sugars subtracted from diets), and ad libitum studies (sugars freely replaced by other macronutrients without control for energy). Outcomes were glycated haemoglobin (HbA1c), fasting blood glucose, and fasting blood glucose insulin.Data extraction and synthesisFour independent reviewers extracted relevant data and assessed risk of bias. Data were pooled by random effects models and overall certainty of the evidence assessed by the GRADE approach (grading of recommendations assessment, development, and evaluation).Results155 study comparisons (n=5086) were included. Total fructose-containing sugars had no harmful effect on any outcome in substitution or subtraction studies, with a decrease seen in HbA1c in substitution studies (mean difference −0.22% (95% confidence interval to −0.35% to −0.08%), −25.9 mmol/mol (−27.3 to −24.4)), but a harmful effect was seen on fasting insulin in addition studies (4.68 pmol/L (1.40 to 7.96)) and ad libitum studies (7.24 pmol/L (0.47 to 14.00)). There was interaction by food source, with specific food sources showing beneficial effects (fruit and fruit juice) or harmful effects (sweetened milk and mixed sources) in substitution studies and harmful effects (sugars-sweetened beverages and fruit juice) in addition studies on at least one outcome. Most of the evidence was low quality.ConclusionsEnergy control and food source appear to mediate the effect of fructose-containing sugars on glycaemic control. Although most food sources of these sugars (especially fruit) do not have a harmful effect in energy matched substitutions with other macronutrients, several food sources of fructose-containing sugars (especially sugars-sweetened beverages) adding excess energy to diets have harmful effects. However, certainty in these estimates is low, and more high quality randomised controlled trials are needed.Study registrationClinicaltrials.gov (NCT02716870).

Apple Preload Halved the Postprandial Glycaemic Response of Rice Meal in Healthy Subjects

“…A meta-analysis of controlled intervention studies reported that the fructose-containing sugar from fresh fruit decreased HbA1c level without any negative metabolic effects on the basis of iso-carbohydrate substitution [23]. The beneficial effect of a small dose of fructose was explained by a 'catalytic' effect of fructose on hepatic glucose uptake [9], which resulted in decreased postprandial GR in high GI meals.…”

“…A number of studies indicate that the substitution of high glycemic index (GI) refined rice with certain fruits or dried fruits can improve postprandial GR [19,20], insulin responses [20], and HbA1c levels [21]. Some fruits rich in fructose such as apples have been proven to be low GI food [22], and the inclusion of fruit-source fructose to background diet based on isocaloric treatments reduced HbA1c in human trials [23]. A meta-analysis of observational studies concluded that temperate fruit consumption is negatively associated with the risk of diabetes and can be included in the diet of the diabetics [24].…”

Are Liquid Sugars Different from Solid Sugar in Their Ability to Cause Metabolic Syndrome?

“…Several meta‐analyses have challenged the concept that fructose may have a role in metabolic syndrome . However, these trials included all fructose sources, including natural fruits.…”

Dietary Fructose and Risk of Metabolic Syndrome in Chinese Residents Aged 45 and Above: Results From the China National Nutrition and Health Survey

“…Some of them concluded that intakes of fructose were associated with increased risk of obesity, dyslipidemia, and hypertension (8)(9)(10). However, some of them found that a certain dose of fructose has no adverse or even some positive effects on fasting glucose, blood pressure, and blood lipids (11)(12)(13)(14)(15). Most of the studies included in these meta-analyses were interventional studies with high-dose fructose intake.…”