Toxic Food Additives: Part III- Aspartame

Introduction

Apartame is an artificial sweetner (one of the sugar substitutes used by people with diabetes) commonly added to many packed food dishes and beverages like soft drinks and is an ingredient of approximately 6,000 other consumer foods and beverages sold worldwide. It is often provided as a table condiment. It is also used in some brands of chewable vitamin supplements and common in many sugar-free chewing gums. This sweetener is marketed under a number of trademark names, including Tropicana Slim, Equal, NutraSweet, and Canderel.In the European Union, it is also known under the E number (additive code) E951.

Chemistry

Aspartame is chemically a peptide with phenylalanine and aspartic acids. It usually breaks down at high temperature and loses its sweetness. It may be represented by ball and stick model as given below:

Ball-and-stick Model

Chemical Structure

Brief History

It was discovered by accident by James Schlatter, a chemist of G D Searle Co. in 1965, when he was testing an anti-ulcer drug. Its use in carbonated drinks was finally approved in 1983

Toxicity
This sugar substitute was hailed as the savior for dieters who for decades had put up with saccharine's unpleasant after taste. There are quite a few problems with aspartame.

1) The first is in phenylketonuria (PKU)

One out of 20,000 babies is born without the ability to metabolize phenylalanine, one of the two amino acids in aspartame. Toxic levels of this substance in the blood can result in mental retardation. Beyond PKU several scientists believe that aspartame might cause altered brain function and behavior changes in consumers. And many people have reported dizziness, headaches, epileptic-like seizures, and menstrual problems after ingesting aspartame.

2) Aspartic acid

Metabolism of aspartame also releases aspartic acid, which is a polar amino acid. Though, it can't permeate blood-brain-barrier (BBB), yet it is reported to cause neurotoxicity when aspartame is ingested above normal range. This might probably be due to neurotoxicity in parts of brain where BBB is absent.

3) Methanol and formaldehyde

Aspartame also releases methanol (though in minute quantity) in intestine, which is inturn metabolized to formaldehyde. Methanol, as is quite well-known, is toxic especially to eyes. But few scientists believe that such minute quantities of methanol virtually have no toxicity as few fruits have more methanol than that is obtained from aspartame. But others believe that the absence of ethanol (which blocks conversion of methanol to ethanol) in aspartame might be responsible for methanol toxicity from aspartame.

4) Aspartylphenylalanine Diketopiperazine (DKP)

The release of DKP leads to its nitrosation in stomach which has a high potential to cause brain tumour. Hence, aspartame is reported to be carcinogenic in nature.

Reference Links:

1) http://www.3dchem.com/molecules.asp?ID=24

2) http://en.wikipedia.org/wiki/Aspartame_controversy

3) http://en.wikipedia.org/wiki/Aspartame