“Problem is, while the lie may be sweet as it falls from your lips, the feeling in your gut is always putridly sour. And almost always bang-on.”
— Caz Frear, Sweet Little Lies
Nearly the same, but in reverse, could be said about consuming sugar substitutes. This week’s Study Spotlight focuses on the largest and longest prospective study to date investigating the association between artificial sweetener consumption and cognitive decline. This study adds an accelerated rate of cognitive decline to the list of chronic disabilities and diseases associated with the consumption of artificial sweeteners, including type II diabetes, cardiovascular disease, and depression.
A previous Study Spotlight focusing on erythritol highlighted these issues. This week’s study added powerful and consistent evidence regarding the potential dangers of consuming large amounts of ultra-processed foods (UPFs).
- The study consisted of 12,772 adults participating in the Brazilian Longitudinal Study of Adult Health, followed for a median of eight years.
- The participants underwent standard cognitive tests every 4 years across three study waves (2008-2010, 2012-2014, and 2017-2019).
- Food consumption was measured with food frequency questionnaires.
- The sugar substitutes examined included the artificial sweeteners aspartame, saccharin, and acesulfame-K; the sugar alcohols erythritol, sorbitol, and xylitol; and tagatose, a natural sweetener.
- Those consuming the greatest quantity of sugar substitutes (191 mg per day – the equivalent of one can of diet soda containing aspartame) had an astounding 62% faster decline in overall thinking and memory skills.
- The middle group of consumers had a 35% faster rate of cognitive decline.
- Compared to the lowest group of consumers (an average of 20 mg per day), this was the equivalent of an accelerated 1.6 years of aging for the highest group of consumers and 1.3 years of accelerated aging for the middle group of consumers.
- The strongest link between consumption and cognitive decline was found in those under 60 years of age and diabetics.
The Caveat:
The loss of cognitive decline was accompanied by deficits in verbal fluency. The highest and middle tertiles of combined low- and no-calorie sweetener consumption showed 110% and 173% higher rates of decline in verbal fluency, respectively. What was particularly concerning regarding the findings of this study is that the most potent effects were seen in younger adults, those less than 60. This suggests that the consequences of consuming large amounts of these sugar substitutes in midlife are impacting the brain in a way that only manifests years or decades later.
These types of findings also impact dietary recommendations for those already suffering from chronic disabilities and diseases such as metabolic syndrome, type II diabetes, cerebrovascular disease, and cardiovascular disease. This is particularly true, as UPFs manufactured with sugar substitutes are often marketed as ‘healthier’ alternatives.
Limitations of the study include the exclusion of certain artificial sweeteners (e.g., sucralose) and the use of food frequency questionnaires for sampling, which have known limitations. Finally, the diet was assessed only at baseline, which may not reflect dietary changes over time.
The Study:
