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Dietary antioxidants, cognitive function and dementia--a systematic review
Georgina E Crichton1, Janet Bryan, Karen J Murphy
1Nutritional Physiology Research Centre, University of South Australia, Adelaide, Australia.
Plant Foods for Human Nutrition (Dordrecht, Netherlands)
|July 25, 2013
Summary
Dietary antioxidants, like vitamins C and E, may not consistently protect against cognitive decline or dementia. Current evidence is mixed, suggesting more research is needed on their long-term effects on brain health.
Area of Science:
- Nutrition Science
- Neuroscience
- Epidemiology
Background:
- Antioxidants from fruits, vegetables, and tea are thought to protect against age-related cognitive decline by reducing oxidative stress.
- However, existing research on the link between antioxidant intake and cognitive health has yielded conflicting results.
- This highlights the need for a comprehensive review of current evidence.
Purpose of the Study:
- To systematically review epidemiological and longitudinal studies on the association between habitual dietary antioxidant intake and cognitive function.
- To examine the impact on overall cognitive performance and the risk of dementia, including Alzheimer's disease and vascular dementia.
- To synthesize current evidence regarding the protective role of antioxidants in maintaining brain health.
Main Methods:
- Systematic literature search of electronic databases for peer-reviewed articles.
- Inclusion of studies reporting on antioxidant intakes (vitamins C, E, flavonoids, carotenoids) and cognitive function or dementia risk.
- Analysis of eight cross-sectional and 13 longitudinal studies.
Main Results:
- Findings on the association between antioxidant intake, cognitive performance, and dementia risk were mixed.
- Significant heterogeneity in study designs, confounding factor control, cognitive assessment methods, and dietary assessment challenges were noted.
- No consistent evidence emerged to support that habitual dietary antioxidant intake improves cognitive performance or reduces dementia risk.
Conclusions:
- Current evidence does not consistently support a link between habitual dietary antioxidant intake and better cognitive function or reduced dementia risk.
- Inconsistencies may stem from methodological limitations across studies.
- Further intervention trials are recommended to clarify the effects of high antioxidant intake and whole dietary patterns on cognitive health.
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