Direct and indirect cellular effects of aspartame on the brain.

Eur J Clin Nutr. 2008;62(4):451-462; Humphries P, Pretorius E, Naude H.

“As for butter versus margarine, I trust cows more than chemists.”

This quote by nutritionist Joan Dye Gussow shows how our manipulation of nature can get us in trouble.

The paper by Humphries et al. published in the European Journal of Clinical Nutrition raises concern that artificial sweeteners in soft drinks are associated with an increased risk of stroke (HR = 2.96) and dementia (HR = 2.89). This association was not observed with sugar-sweetened beverages. This study does not mean that sugar-sweetened beverages are fine; the negatives consequences of excess sugar intake, including obesity, are well known. However, it appears that artificial sweeteners, mainly aspartame, are not entirely innocent either.

Aspartame is composed of 50% phenylalanine, 40% aspartic acid, and 10% methanol. One of several potentially toxic byproducts of aspartame is formaldehyde. The study raises concern that intracellular toxicity of aspartame can lead to strokes, dementia, malignancies and learning disabilities.

This was an observational study, and therefore no causation can be made. A particular caveat is that participants with diabetes, who are more likely to develop stroke and dementia, also consumed more artificially sweetened drinks. While the authors adjusted for diabetes in their analysis, it is likely that some residual confounding has not been completely eliminated.

The study of Humphries et al. is a reminder that we can’t fool nature. Just as butter is better than trans fatty acids in margarine, sugar – in a modest amount! – is likely better in the long term for one’s health than artificial chemical products.