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The dose – dependent effects of Aspartame on Serotoninergic Parameters in Albino Rats

Iwalokun, B.A
Department of Biochemistry, Lagos State University, P.M.B. 1087 Apapa – Lagos Nigeria

Scientific evidence to validate anecdotal claims that aspartame (ASP), a low calorie sweetener may modulate Serotoninergic mediated behaviours remains inconclusive. This study determined the effects of ASP on plasma tryptophan, serotonin, monoamine oxidase (MAO) activity and platelet aggregation in rats intraperitoneally administered with 40, 100 and 200 mg/kg doses over 14 days. The sweetener induced dose – dependent decreases in MAO activity (9.27 – 4.16 unit/ml vs. 11.4 units/ml) and plasma levels of tryptophan (10.4 – 5.8 mM vs. 14.7 mM) and platelets serotonin (7.3 – 2.6ng/ml vs. 8.6ng/ml) when compared to the control with ASP200 eliciting significant effects (P < 0.05). ASP100 and ASP200 further caused moderate (1.95 + 0.2ng/ml vs. 1.30 + 0.07ng/ml, P > 0.05) and significant (P < 0.05) elevation in free plasma serotonin in the experimental animals. The increased platelet aggregation induced by ASP200 associated strongly with platelets serotonin level (r = - 0.63; P < 0.05) but weakly with plasma free serotonin (r = 0.14; P > 0.05). The results of this study have provided a strong indication that aspartame may alter serotoninergic parameters and associated behaviours when consumed at doses greater than 100mg/kg per day. The healthiness inherent in acceptable daily intake compliance of aspartame in foods, candies and beverages is discussed.

[ACSN Founder has been talking about aspartame's negative effects on serotonin production for almost two decades. See Transcript of Lecture at UT Southwestern Medical School: ]