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News Article

High protein diet may protect against Alzheimer's in elderly.

A cross-sectional study in elderly people suggests those with the highest protein intake have the lowest brain amyloid-beta levels.

Following a diet with higher amounts of protein may decrease risk of Alzheimer’s in older people, suggests a study that compares diets and levels of amyloid-beta protein, a predictor of later Alzheimer’s disease. Those on the highest protein diets had the lowest amyloid-beta accumulation in their brains. The study was published in Journal of Alzheimer’s Disease.

 Many nutrients have been examined for their effects on Alzheimer’s risk but it seems protein has not been extensively studied. A systematic review of dietary protein in older adults in 2015 analysed the few observational studies in existence and found no evidence to support the idea that protein intake could affect cognitive function in the elderly. A randomised controlled trial that wasn’t included in the systematic review found that consuming 15 g protein supplements twice daily had no effect on cognition in 65 elderly people in a 24 week study.

The study reported this week was from researchers across Australia led by Binosha Fernando and Stephanie Rainey-Smith from Edith Cowan Universityand it examined 541 people with normal cognition aged more than 60 years, who were taking part in a larger study of aging (the Australian Imaging, Biomarkers and Lifestyle Study). It assessed their diet using food frequency questionnaires and in 162 it assessed their brain amyloid-beta levels using a PET scan.

The subjects consumed an average of 84.4g protein a day. The study found no associations between blood amyloid levels and protein intake. However when the researchers ranked the 162 subjects who had PET scans by protein consumption level, they discovered that those consuming the least protein (around 54.4 g/day), had a greater chance of having raised levels of amyloid-beta proteins in their brains than those consuming most protein (about 118 g/day). Even those in the mid-range of consumption were more likely to have raised levels of amyloid-beta. The odds for high amyloid-beta in the brain were increased 12.59 and 8.53 times respectively. The researchers defined ‘High amyloid’ as PiB PET SUVR>1.5. (SUVR=standardised uptake value ratio).

They point out that a study that follows subjects over a period of years is needed to confirm this finding.

 Associations of Dietary Protein and Fiber Intake with Brain and Blood Amyloid-β. Fernando, W.M.A.D. Binoshaa; Rainey-Smith, Stephanie R.; Gardener, Samantha L.; Villemagne, Victor L.; Burnham, Samantha C.; Macaulay, S. Lance; Brown, Belinda M.; Gupta, Veer Balaa; Sohrabi, Hamid R.; Weinborn, Michael; Taddei, Kevina; Laws, Simon M.; Goozee, Kathryn; Ames, David; Fowler, Christopher; Maruff, Paul; Masters, Colin; Salvado, Olivier; Rowe, Christopher C.; Martins, Ralph N.; For the AIBL Research Group. Journal of Alzheimer's Disease, vol. 61, no. 4, pp. 1589-1598, 2018

Article details

  • Author(s)
  • I. Hoskins
  • Date
  • 02 March 2018
  • Subject(s)
  • Nutrition & disease