|Nutrition is a central factor in today's observed aging of the population. However, the good prospect of longevity is overshadowed by the high prevalence of mental decline in old age. The most prevalent form of neurodegeneration is Alzheimer's disease(AD) reaching a prevalence of over 30 % above age 80.
The question is reviewed whether nutrients may protect or slow down the age associated mental decline due to neuronal degeneration. The amyloid hypothesis states that the amyloid fragment (Abeta) originating from the metabolism of the amyloid precursor protein (APP) is neurotoxic and causes the damage to the neurons. The most popular hypothesis states that a deranged APP metabolism increases oxidative stress in addition to age associated increase. Thus, antioxidative nutrients could potentially protect against AD.
Numerous observational studies demonstrate a positive correlation between a high intake of antioxidants and better cognitive function in the elderly; however these studies need to be interpreted with caution. Randomized controlled studies over sufficient long periods are not possible.
A hypothesis gaining today more weight are the age-related proinflammattory cytokines. Observational studies show a reduced risk of AD in users of nonsteroidal anti-inflammatory drugs. Also omega-3 fatty acids are known to reduce cytokines could then lower the AD risk.