Antioxidant Intake – Lower Risk of Alzheimer’s Disease

An Examination of Two Studies Published by JAMA (The Journal of the American Medical Association) – June 26, 2002

The consistency of findings in these two independent cross-national studies is notable. The similarity of the results–which were generated using similar, standardized methods in Chicago (US) and Rotterdam (The Netherlands)–provides persuasive support for the idea that antioxidant-rich foods may have a beneficial impact on the development of Alzheimer’s disease (AD). Several previous findings suggest that oxidative stress may play an important role in the development of AD, which is now the 6th-leading cause of death among adults [online source: Alzheimer’s Association], and is expected to afflict an estimated 14 million people within the next 50 years, leading some to call it the “health care challenge of the 21st century!” In the United States, the current estimate of 360,000 new cases of AD each year is expected to triple in the next 40 years! Even modestly effective interventions that delay the onset of this terrible disease by one to three years will substantially alleviate its growing economic and societal burden.

  1. Dietary Intake of Antioxidants and Risk of Alzheimer Disease (pages 3223-3229)
  2. Dietary Intake of Antioxidant Nutrients and the Risk of Incident Alzheimer Disease in a Biracial Community Study (pages 3230-3237)

In both of these observational studies, higher dietary intake of antioxidants–especially vitamin E–was found to be associated with a lower risk of incident Alzheimer’s Disease (AD).  The result was less clear, overall, with vitamin C. In the Chicago Health and Aging Project, persons in the highest category of vitamin E intake from food were 70% less likely than those in the lowest category of intake to be diagnosed with AD! The overall Chicago findings for vitamin C–which cranberries are very high in–were not statistically significant in this study but remain suggestive enough to be of interest for further study. The Chicago findings were based on new cases developing in an average 3.9-year interval between the baseline and follow-up examination among 815 men and women, black and white, aged 65 years and older.

Rotterdam Study: In the Rotterdam Study, persons in the highest category of vitamin E intake from food were 43% less likely to develop AD compared with those in the lowest category of intake. High intake of vitamin C had a borderline significant association with risk of AD in all models. But when additional adjustments were made for education, smoking habits, pack-years of smoking, body mass index, total energy intake, presence of carotid plaques, and use of antioxidative supplements, high intake of vitamin C was found to be significantly related to reduced risk of AD. Men in this study tended to have a higher intake of vitamin E, fat and beta carotene, and a lower intake of vitamin C as compared with the women in the study. The findings in this study were based on an average follow-up period of 6 years among 5,395 men and women aged 55 years and older.

Side Notes:

  • Flavonoids are phenolic plant pigments, with high anti-oxidative power within the human body. Ripe, RED cranberries are understandably high in flavonoid content, and are the 1st of 3 flavonoid examples cited in the Rotterdam study, page 3224!! (The other two are green & black tea, and pulses.)
  • For smokers in this study, beta carotene and flavonoids also seemed to have a protective effect.