Alzheimer's disease is the most common type of senile dementia and is characterized by short-term memory loss, reduced cognitive abilities and inappropriate behavior. The American Health Assistance Foundation cites that over 26 million people are diagnosed with Alzheimer's globally, including 5 million in the U.S. However, researchers have noticed that India's incidence of Alzheimer's is very low and have considered the benefits of curry powder. The main ingredient of curry being researched is turmeric root, which contains the biologically active compound, curcumin.
Curcumin Protects Myelin
Growing evidence suggests that curcumin may afford protection against neurodegenerative diseases, such as Alzheimer's and multiple sclerosis, by keeping myelin from being destroyed. Myelin is the protective sheath that surrounds most nerves in the body. While it is still unclear how curcumin affords protection against degeneration, one theory is that it interrupts the production of IL-2, a protein that plays an important role in the destruction of myelin.
Curcumin Stimulates Production of Antioxidants
Some studies have suggested that curcumin protects against Alzheimer's disease by turning on a gene that codes for the synthesis of antioxidant proteins. A 2003 study published in the "Italian Journal of Biochemistry" found that curcumin turns on the gene hemeoxygenase-1 in the hippocampal part of the brain, which causes the production of bilirubin, a powerful antioxidant. Bilirubin protects the brain from oxidative damage caused by free radicals, which scientists think is a primary reason for aging and responsible for neurodegenerative disorders, including Alzheimer's.
Curcumin Inhibits Amyloid Plaque Formation
A defining physical characteristic of Alzheimer's is the formation of insoluble amyloid protein fragments, which accumulate in brain cells and produce oxidative stress and inflammation. The amyloid fragments enlarge with time, forming plaques between neurons in the brain that disrupt cognitive function. A 2004 UCLA study published in the "Journal of Biological Chemistry" found that curcumin crosses the blood-brain barrier and binds to amyloid protein fragments, preventing them from aggregating together into plaques.
In addition to preventing amyloid plaque formation, curcumin also boosts plaque clearance in Alzheimer's patients by stimulating the immune system to produce macrophage cells. In healthy patients, macrophage cells engulf and destroy pathogens and efficiently clear amyloid protein deposits, but macrophage activity is suppressed in Alzheimer's patients. A 2007 study published in "Proceedings of the National Academy of Sciences U.S.A.," found that curcumin boosts macrophage activity to normal levels by enhancing gene transcription, which helps dissolve amyloid plaques. A prior study investigating curcumin's effects on amyloid plaques in the brains of mice demonstrated how effective it can be by reducing 30 percent of the plaques in a single week.
References
- American Health Assistance Foundation: Alzheimer's Disease Research: The Facts on Alzheimer's Disease
- "Genes and Immunity"; Peroxisome Proliferator-Activated Receptor-Gamma Agonists Inhibit Experimental Allergic Encephalomyelitis By Blocking IL-2 Production, IL-12 Signaling and Th1 Differentiation; C. Natarajan et al.; April 2002
- PubMed.gov: "Italian Journal of Biochemistry"; Nutritional antioxidants and the heme oxygenase pathway of stress tolerance: novel targets for neuroprotection in Alzheimer's disease; V. Calabrese et al.; December 2003
- "Journal of Biological Chemistry"; Curcumin Inhibits Formation of Abeta Oligomers and Fibrils and Binds Plaques and Reduces Amyloid in Vivo; F. Yang et al.; December 2004
- PubMed.gov: "Proceedings of the National Academy of Sciences USA"; Innate Immunity and Transcription of MGAT-III and Toll-Like Receptors in Alzheimer's
- "Journal of Neuroscience"; The Curry Spice Curcumin Reduces Oxidative Damage and Amyloid Pathology in an Alzheimer Transgenic Mouse; G. Lim et al.; November 2001
