Metabolic effects of aspartame in adulthood: a systematic review and meta-analysis of randomized clinical trials

<b>Background</b>: Data about harms or benefits associated with the consumption of aspartame, a non-nutritive sweetener worldwide consumed, is still controversial. This systematic review and meta-analysis of randomized controlled clinical trials aimed to assess the effect of aspartame consumption on metabolic parameters related to diabetes and obesity. <b>Methods</b>: The search was performed on Cochrane, LILACS, PubMed, SCOPUS, Web of Science databases and on a grey literature using Open Grey, Google Scholar and ProQuest Dissertations &amp; Theses Global. Searches across all databases were conducted from the earliest available date up to April 13, 2016, without date and language restrictions. Pooled mean differences were calculated using a random or fixed-effects model for heterogeneous and homogenous studies, respectively. <b>Results</b>: Twenty nine articles were included in qualitative synthesis and twelve, presenting numeric results, were used in meta-analysis. Fasting blood glucose (mmol/L), insulin levels (μU/mL), total cholesterol (mmol/L), triglycerides concentrations (mmol/L), high-density lipoprotein cholesterol (mmol/L), body weight (Kg) and energy intake (MJ) were considered as the main outcomes in subjects that consumed aspartame and results were presented as (mean difference; % Confidence Interval, range). Aspartame consumption was not associated with alterations on blood glucose levels compared to control (−0.03 mmol/L; 95% CI, −0.21 to 0.14) or to sucrose (0.31 mmol/L; 95% CI, −0.05 to 0.67) and on insulin levels compared to control (0.13 μU/mL; 95% CI, −0.69 to 0.95) or to sucrose (2.54 μU/mL; 95% CI, −6.29 to 11.37). Total cholesterol was not affected by aspartame consumption compared to control (−0.02 mmol/L; 95% CI, −0.31 to 0.27) or to sucrose (−0.24 mmol/L; 95% CI, −0.89 to 0.42). Triglycerides concentrations were not affected by aspartame consumption compared to control (0.00 mmol/L; 95% CI, −0.04 to 0.05) or to sucrose (0.00 mmol/L; 95% CI, −0.09 to 0.09). High-density lipoprotein cholesterol serum levels were higher on aspartame compared to control (−0.03 mmol/L; 95% CI, −0.06 to −0.01) and lower on aspartame compared to sucrose (0.05 mmol/L; 95% CI, 0.02 to 0.09). Body weight did not change after aspartame consumption compared to control (5.00 Kg; 95% CI, −1.56 to 11.56) or to sucrose (3.78 Kg; 95% CI, −2.18 to 9.74). Energy intake was not altered by aspartame consumption compared to control (−0.49 MJ; 95% CI, −1.21 to 0.22) or to sucrose (−0.17 MJ; 95% CI, −2.03 to 1.69). <b>Conclusions</b>: Data concerning effects of aspartame on main metabolic variables associated to diabetes and obesity do not support a beneficial related to its consumption.