Written by Angeline A. De Leon, Staff Writer. Study results demonstrated that sugary beverage consumption significantly decreased performance on episodic memory tests and reduced total brain volume in 4276 participants, leading researchers to validate an association with preclinical Alzheimer’s.
Excessive consumption of sugar is a major public health concern, particularly in Western regions of the world. While U.S. dietary guidelines recommend for adults to consume less than 10% of their calories from added sugar 1, the presence of high-sugar products, including sugar-sweetened soft drinks, fruit drinks with added sugar, and 100% fruit juice 2, remains ubiquitous throughout the American consumer market. The average serving of children’s fruit juice, for example, typically contains sugar concentrations which exceed that of their recommended daily allowance 3. Studies in animal research have shown that high sugar intake, from dietary sources including sugary beverages, is linked to correlates of Alzheimer’s Disease (AD), including poor memory, atrophy of the hippocampus (major brain area supporting memory function), and accumulation of beta amyloids (protein fragments known to contribute to harmful plaque formation in the brain) 4-6. Newer research is looking at the impact of prolonged consumption of sugary beverages on the structure and function of the human brain. One such study, published by Alzheimer’s & Dementia in 2017, explored the relationship between sugary beverage intake and markers of preclinical AD, using a combination of neuropsychological testing and brain imaging.
Employing an observational, cross-sectional design, the study involved a large, community-based, prospective cohort from Massachusetts. Participants (average age of 54 years) completed the Harvard Food Frequency Questionnaire, FFQ, a self-report measure used to estimate dietary intake of (1) total sugary beverages, (2) fruit juice, (3) sugar-sweetened soft drinks, and (4) diet soft drinks over the past year. Following the FFQ, subjects underwent a cognitive battery of neuropsychological measures (n = 4276) (assessing verbal memory, processing speed, and other executive functions) and a structural brain scan (n = 3846) (measuring total brain volume and hippocampal volume as markers of early neurodegeneration 7.
Results of the investigation demonstrated that higher consumption of sugary beverages, relative to minimal consumption (less than one per day), was associated with worse performance on tests of episodic memory (p < 0.01 across all subtests). Greater intake of sugary beverages was also linked to reduced total brain volume: 1-2 drinks per day = -0.55 +/- 0.14 mean percent difference (p < 0.0002); 2 or more drinks per day = -0.68 +/- 0.18 mean percent difference (p < 0.0001). In similar fashion, one or more servings of fruit juice per day were found to be correlated to lower total brain volume (p < 0.05) and hippocampal volume (p < 0.05) as well as poorer performance on episodic memory (p < 0.05).
Overall, findings show that consistent with animal models, higher sugary beverage intake in humans is associated with preclinical Alzheimer’s. Researchers observed that the strength of the correlations found were comparable to “1.5-2.6 years of brain aging for total brain volume and 3.5-13 years of brain aging for episodic memory.” Evidence suggests, therefore, that dietary regulation of sugar intake is critical in guarding against the brain atrophy and memory impairment associated with accelerated aging and AD. Because of the cross-sectional nature of the study, further research is needed to replicate findings and evaluate the longitudinal relationship between sugary beverage consumption and progression of preclinical AD.
Source: Pase MP, Himali JJ, Jacques PF, et al. Sugary beverage intake and preclinical Alzheimer’s disease in the community. Alzheimer’s & Dementia. 2017; 0(0): 1-10. DOI: http://dx.doi.org/10.1016/j.jalz.2017.01.024.
© 2017 the Alzheimer’s Association. Published by Elsevier Inc. All rights reserved.
Posted May 8, 2017.
Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program.
References:
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- Frisoni GB, Fox NC, Jack CR, Scheltens P, Thompson PM. The clinical use of structural MRI in Alzheimer disease. Nature Reviews Neurology. 2010;6(2):67-77.
