Effects of aspartame on the evaluation of electrophysiological responses in Wistar albino rats

Abstract

Aspartame is a non-nutritive sweetener that is used predominantly in various 'diet' and 'low-calorie' products, such as beverages, instant breakfasts, desserts, breath mints, sugar-free chewing gum, vitamins, and pharmaceuticals, consumed by millions of people who are attempting weight loss, young adults and diabetic persons. On a weight basis, the metabolism of aspartame generates approximately 50% phenylalanine, 40% aspartic acid and 10% methanol. The detailed mechanisms of the effects of aspartame on the electrophysiological response are still unclear; therefore, this study was designed to clarify whether longer-term aspartame consumption has any effect on the electrophysiological response in Wistar albino rats. The oral administration of aspartame in a safe dose of 40 mg/kg bodyweight/day (as recommended by EFSA, 2012) was tested in Wistar albino rats for a longer period (90 days). Electrophysiological responses, including heart rate variability (HRV) and electroencephalogram (EEG) pattern, were assessed in a folate-deficient animal model along with control animals using BIOPAC and EEG equipment (model RMS EEG-24 brain new-plus: RMS-Recorder and Medicare systems). In this study, the folate-deficient animal model was used to mimic human methanol metabolism in rats. After 90 days of aspartame treatment, a significant alteration was observable in the time domain [Mean RR (ms) SDNN (ms) RMSSD (ms) PNN50 (%)] and the frequency domain [LF, HF, and LF/HF ratio] with significantly impaired frequency and amplitude of the fronto-parietal and occipital EEG waves at p ≤ 0.05. The results of this study clearly indicate that the oral consumption of aspartame reduced HRV, with sympathetic dominance and loss of vagal tone, and altered sympathovagal activity along with impairment of learning and memory, showing an additional effect on health within this study duration. The aspartame metabolites methanol and formaldehyde may be the causative factors behind the change observed.

Role of L-carnitine in protection against the cardiac oxidative stress induced by aspartame in Wistar albino rats

“…The present data indicate that the activity of SOD decreased significantly in the cardiomyocytes during the ASP treatment. The literature has shown that ASP chronic administration causes SOD activity to decline the liver and renal tissues [ 5 , 16 ], the spleen, thymus, lymph nodes, and bone marrow of rats [ 1 ]. The increased reactive oxygen species levels in the human heart are concerned with aortic valve stenosis [ 40 ].…”

“…Aspartame (ASP) is metabolized in the gastrointestinal tract and is absorbed by circulating blood as 50% phenylalanine, 40% aspartic acid, and 10% methanol, which causes the toxicity of ASP as described in detail previously [ 1 ]. The USA and Europe have recommended the acceptable daily intake of ASP as 50 and 40 mg/kg of body weight, respectively [ 2 ].…”

Aspartame: Should Individuals with Type II Diabetes be Taking it?

“…Aspartame ingestion result in sympathetic dominance with loss of vagal tone and impaired cardiac function in rats [83,84]. Mostly Hypercortisolism is associated with central obesity, insulin resistance, dyslipidemia, and alterations in clotting and platelet function [85] (see Figure 3A and B).…”

“…Aspartame induces excess free radical production, in particular, reactive oxygen species (ROS) and reactive nitrogen species (RNS). These free radicals result in systemic oxidative stress [23] such as in blood cells [50,89,[115][116][117], brain cells [16,110,111,118,119], liver and kidney cells [20,22,120], heart cells [83,84] and immune organs [15,[121][122][123] (Figure 5). Systemic oxidative stress is associated with insulin resistance [124].…”

Chronic Unpredictable Stress-Induced Behavioral and Electrophysiological Alterations and Its Ameliorative Effect by Myricetin Microemulsion

“…Recordings were analyzed by RMS EEG-24 Super sec version 1.1 and expressed in terms of amplitude (µv) and frequency (Hz). All experiments were performed at the same time of day (8:00:00-12:00 am) to eliminate variation due to circadian rhythms [29].…”