Associations of Dietary Protein and Fiber Intake with Brain and Blood Amyloid-β.
Level 4 - case-series / case-control
Cross-sectional observational biomarker study
PubMed 29376865 · doi:10.3233/JAD-170742
What was done
Cross-sectional study examining the association between self-reported dietary protein and fiber intake and amyloid-β (Aβ) biomarkers in cognitively normal older adults from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study. Biomarker measurements included plasma Aβ (n = 541) and brain Aβ burden quantified via PiB PET standardized uptake value ratio (SUVR, n = 162).
What was found
Participants in the lowest and middle tertiles of protein intake showed 12.59-fold (p = 0.008) and 8.43-fold (p = 0.013) higher odds of high brain Aβ burden (PiB PET SUVR ≥ 1.5), respectively, compared with the highest tertile. No other significant associations were observed, including any relationships with fiber intake or plasma Aβ.
Why it matters
Provides early biomarker-level observational evidence that higher dietary protein intake may be linked to lower brain amyloid burden in older adults before objective cognitive decline occurs.
Limits
Cross-sectional observational design cannot determine causality or temporal sequence. Dietary intake relied on self-report, which is prone to measurement error and recall bias. The brain imaging subgroup was relatively small (n = 162), confidence intervals for the large odds ratios were not provided in the abstract, and findings require longitudinal validation.
Cited by
- supports Studies show that people who consume higher amounts of dietary protein tend to have lower amyloid burden in the brain.