Aspartame is an artificial sweetener that is increasingly being added to a greater number of foods. The aspartame molecule is comprised on three main components, the amino acids L-aspartate and L-phenylalanine, as well as methanol. The methanol fraction of the molecule can be metabolised in the liver to formaldehyde, and the aspartate and phenylalanine components can pass into the brain where they can become used as neurotransmitters, directly in the case of aspartate, or indirectly through the synthesis of dopamine and noradrenaline in the case of phenylalanine. The upper safety limit of aspartame is not known, but regulatory bodies in the United states and Europe consider 40 to 50 mg per kg body weight as the upper limit of known safety. However, dosage above 25 mg per kg body weight as considered excessive and at this dosage and above the side effects of aspartame may become more evident. A number of studies have looked at the negative effects of high intakes of aspartame.
Aspartame at 25 mg per kg body weight shows detrimental effects on mental function and can increased depressive symptoms. For a 75 kg typical adult male, 25 mg per kg body weight equates to 1875 mg of aspartame. A typical can of diet cola can contain just under 200 mg of aspartame, and so around 9 or 10 cans of soft drink per day would be required to provide this amount of aspartame. However, aspartame is appearing in more and more foods and so it is likely that a high processed food diet may provide a significant amount of aspartame. The estimated average aspartame intake may range from between 400 to over 500 mg of aspartame in those consuming a typical Western diet containing artificially sweetened foods. Therefore while the argument that consumption of aspartame for most individuals is below the recommended upper limit, it is not beyond the realms of possibility that firstly, some individuals are consuming amounts of aspartame that are close to this limit, and that secondly, some individuals may be susceptible to the detrimental effects of aspartame at much lower doses than those identified. Advice for good health should be always to avoid artificially sweetened foods.
For example, in one study a group of researchers investigated the effects of aspartame on a group of otherwise healthy individuals. Subjects were fed either a low aspartame diet for 8 days which consisted of 10 mg per kg body weight aspartame or a high aspartame diet that consisted of 25 mg per kg body weight aspartame for 8 days. All subjects consumed both diets in a random order with a 2 week period between switching diets. The results of the study showed that the consumption of the high aspartame diet was associated with irritability, depressive symptoms and a worse performance in spatial orientation tests. The authors concluded that based on the fact that the levels tested in this study were well below the maximum intake level of around 40 mg per kg body weight, there is cause for caution in individuals consuming aspartame containing products in order to ensure that their health is not negatively affected. This supports data from other studies that show detrimental health outcomes from aspartame consumption.
Eat Well, Stay Healthy, Protect Yourself
RdB
