Alzheimer's disease is a neurological disorder in which irreversible progressive deterioration of the brain causes symptoms of memory loss, confusion, irritability, difficulties with speech, cognitive impairment and movement disorders. An article in the January 2010 issue of the "Journal of Alzheimer's Disease" reports that it is the most common cause of dementia and its prevalence is one in four people over the age of 85. In Alzheimer's disease, oxidative stress plays a role in the degeneration of the brain and diets high in certain antioxidants are protective against the disease.
Melatonin
Melatonin is a potent antioxidant and a review in the "Journal of Alzheimer's Disease" reports that in animal models of Alzheimer's disease, melatonin decreased oxidative stress, reduced amyloid plaque formation and increased cognitive performance. A clinical trial was initiated in 2007 to evaluate the efficacy of melatonin treatment to delay the cognitive decline in patients with mild cognitive impairment.
Antioxidant Vitamins
The article in the "Journal of Alzheimer's Disease" notes that vitamin E levels in patients with Alzheimer's disease are significantly lower than in age-matched controls. A study in the July 2010 issue of "Archives of Neurology" reports that patients who had the highest intake of dietary vitamin E had a 25 percent less risk for developing dementia, while there was no decreased risk present in those with a high dietary intake of vitamin C. The review in the "Journal of Alzheimer's Disease" states that other studies have shown vitamin C intake to reduce the incidence of Alzheimer's disease, although it does not appear to be as effective as vitamin E.
Antioxidant Polyphenols
Polyphenols are a group of plant-derived antioxidant chemicals that include resveratrol, curcumin, quercetin and other flavonoids. Resveratrol is found in certain red wines, and red wine consumption has been associated with a decreased risk of Alzheimer's disease. The article in the "Journal of Alzheimer's Disease" reports that the antioxidant activities of curcumin protect against neural cell injury in animal models of Alzheimer's disease. A study in "The Journal of Nutritional Biochemistry" reports that in laboratory experiments quercetin protects against oxidative stress caused by the neurotoxic peptide that forms plaques in the brains of Alzheimer's patients. Currently, clinical trials are ongoing that are evaluating whether resveratrol and curcumin alone and in combination with ginkgo biloba extract slow the progression of Alzheimer's disease.
Ginkgo Biloba Extract
Ginkgo biloba is a tree and extracts from the leaves contain primarily flavonoids and terpenoids. A review article in the journal "The Neurologist" concludes that the overall evidence is weak that extracts from ginkgo biloba provide some cognitive improvement in patients with Alzheimer's disease. This review notes that two large trials that are evaluating whether ginkgo extract is preventive for Alzheimer's disease are ongoing and results are expected in 2010.
References
- "Journal of Alzheimer's Disease"; Neuronutrition and Alzheimer's Disease; Balenahalli N. Ramesh et al.; January 2010
- "Journal of Alzheimer's Disease"; Mitochondria and Antioxidant Targeted Therapeutic Strategies for Alzheimer's Disease; M. Dumont et al.; 2010
- "The Neurologist"; Alternative Medicine and Alzheimer's Disease; Brendan J. Kelley and David S. Knopman; September 2008
- "The Journal of Nutritional Biochemistry"; Protective Effect of Quercetin in Primary Neurons Against Abeta(1-42): Relevance to Alzheimer's Disease; M.A. Ansari et al.; April 2009
- "Archives of Neurology"; Dietary Antioxidants and Long-Term Risk of Dementia; E.E. Devore et al.; July 2010
