Nutrient Intake and Plasma Beta-Amyloid Neurology


alzheimersColumnist Review by Dr. Dan Murphy, D.C. 

Y. Gu, PhD, N. Schupf, PhD, S.A. Cosentino, PhD, J.A. Luchsinger,MD, N. Scarmeas, MD: From the Department of Neurology and Department of Medicine, Columbia University, New York

Key Points From This Study:

  1. An important pathological hallmark of Alzheimer’s disease (AD) is B-amyloid (AB) peptide (mainly AB40 and AB42) deposition in the brain, resulting in formation of plaques.
  2. It is not easy or practical to measure brain AB levels, but plasma AB is easy to obtain and minimally invasive.
  3. These authors examined whether dietary intake of nutrients was associated with plasma AB levels in a cross-sectional analysis of 1,219 persons 65 years or older. Participants were in a community-based multiethnic cohort.
  4. Plasma levels of AB were measured and analyzed against stringent and comprehensive nutrient and supplement data collection.
  5. The associations of plasma AB40 and AB42 levels and dietary intake of 10 nutrients were examined using linear regression models, adjusted for age, gender, ethnicity, education, caloric intake, apolipoprotein E genotype, and recruitment wave.
  6. Nutrients examined included saturated fatty acid, monounsaturated fatty acid, omega-3 polyunsaturated fatty acid (PUFA), omega-6 PUFA, vitamin E, vitamin C, beta-carotene, vitamin B12, folate, and vitamin D.
  7. Higher intake of omega-3 PUFA was associated with lower levels of AB40 (24.7% reduced risk) and lower levels of AB42 (12.3% reduced risk). [Total AB reduced risk of 37%]
  8. Other nutrients were not associated with plasma AB levels.
  9. “Our data suggest that higher dietary intake of omega-3 PUFA is associated with lower plasma levels of AB42, a profile linked with reduced risk of incident AD and slower cognitive decline in our cohort.”
  10. “There is increasing evidence to suggest that diet may play an important role in preventing or delaying the onset of Alzheimer’s disease.”
  11. “The nutrient intakes from foods and from supplements were separately estimated, and only the nutrient intake from foods was used in the current analysis.”
  12.  “Participants with higher omega-3 PUFA also had lower levels of AB40.”
  13. Higher intake of omega-3 PUFA was significantly associated with reduced plasma levels of both AB40 and AB42.
  14. “In this cross-sectional study of a group of elderly participants without dementia, we found that higher dietary intake of omega-3 PUFA was associated with decreased plasma AB42 levels, independent of age, gender, ethnicity, education, and APOE genotype.” [This indicates that even in those with genetic markers of increased Alzheimer’s risk, increasing levels of omega-3 fatty acids reduces the associated risk]
  15. A dietary pattern characterized by high omega-3 PUFA was associated with a nearly 40% reduced risk of AD.
  16. “Higher dietary intake of omega-3 PUFA might lead to lower plasma levels of AB42 (and possibly AB40) and a subsequent lower risk of AD.”
  17. There was no persistent association for other nutrients, suggesting that the nutrients might have little or no association with AB-related mechanisms.
  18. “In the current study, we found that higher dietary omega-3 PUFA intake was associated with lower plasma AB42 level, suggesting that the potential beneficial effects of omega-3 PUFA intake on AD and cognitive function in the literature might be at least partly explained by an AB-related mechanism.”
Comments From Dr. Dan Murphy:
This is yet another article indicating that low levels of omega-3 fatty acids increase the risk of Alzheimer’s disease. It is projected that as the Baby Boomer generation (1946-1964) continues to retire, about 14 million of them will suffer from Alzheimer’s, a burden to our society that threatens to bankrupt our country. I believe that all Americans should have their omega-6/omega-3 ratio checked and we should all strive to keep our ratio below 4/1.

Dr. Dan Murphy graduated magna cum laude from Western States Chiropractic College in 1978. He received Diplomat status in Chiropractic Orthopedics in 1986. Since 1982, Dr. Murphy has served part-time as undergraduate faculty at Life Chiropractic College West, currently teaching classes to seniors in the management of spinal disorders. He has taught more than 2000 postgraduate continuing education seminars.  Dr. Murphy is a contributing author to both editions of the book Motor Vehicle Collision Injuries and to the book Pediatric Chiropractic. Hundreds of detailed Article Reviews, pertinent to chiropractors and their patients, are available at Dr. Murphy’s web page:

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