Curcumin is an anti-inflammatory molecule found in the turmeric root. Turmeric has been widely used as a preservative and coloring agent in food, and has also been used for centuries for medicinal purposes in various cultures. India has a low prevalence of Alzheimer’s disease in its populace, which potentially could be due to genetics or a specific dietary factor. Some people attribute the low incidence of Alzheimer’s in Asia to their high dietary intake of turmeric. On average, turmeric contains approximately 5-10% curcumin, which is calculated as a daily intake of curcumin in India of approximately 125mg.1
The study investigated the ability of curcumin (a component of turmeric) to prevent amyloid plaque formation in the brain of a living organisms, namely in mice that have a tendency to form the same plaques that are seen in human Alzheimer’s disease. The researchers found that plaques were visibly reduced throughout the cortical and hippocampal brain areas in curcumin-fed mice compared with the mice fed the control diet. There was a significant reduction in plaque burden and levels of the insoluble Aβ. They concluded that curcumin has potent anti-amyloidogenic activity (inhibiting amyloid deposits), even in aged animals.2
Researchers are exploring the possible scientific basis for these hypothesized benefits of curcumin intake. In one study researchers raised transgenic mice (mice genetically modified to have a condition that mimics Alzheimer’s disease) fed a basic diet supplemented with 500ppm curcumin and a control set of mice fed a safflower oil-based diet to the age of 22 months. The curcumin was added into the food of the treatment group of mice beginning at 17 months, an age when amyloid accumulation is as great or greater than in human Alzheimer’s disease brains.
At 22 months, three of the mice were anesthetized. One was injected with curcumin into the carotid artery, and the other two were injected with saline only as a control. One of these two mice had received the curcumin diet. The brains of the mice were removed and frozen, examined, and photographed.
Amyloid levels were evaluated in the cortex of the control (n = 6) and curcumin-fed (n = 4) transgenic mice. The researchers believed that because curcumin is highly hydrophobic (repels or fails to mix with water), it would readily enter the brain to bind to plaques in vivo (in a living organism). In order to evaluate their hypothesis, they injected curcumin or saline into the carotid artery of aged transgenic mice, and anesthetized them an hour after so to examine their brain. The control mice injected with saline only showed no plaque staining. However, a mouse on the chronic curcumin diet of 500 ppm showed discernable but weak plaque staining when injected with saline alone. The plaques in the curcumin-injected mouse were brightly marked. The researchers concluded that these data suggested curcumin can cross the blood-brain barrier and bind to plaques in transgenic mice after oral feeding of curcumin or peripheral injection of curcumin.
The researchers also tested whether curcumin was better than nonsteroidal anti-inflammatory drugs (NSAIDs) at inhibiting amyloid β (Aβ) accumulation. Their data indicate that although high concentrations of naproxen and ibuprofen can inhibit Aβ aggregation, curcumin is a better aggregation inhibitor.
- Mary S. Eaton Translational Alzheimer’s Research Center. Curcumin. http://alzheimer.neurology.ucla.edu/Curcumin.html
- Yang F, Lim GP, Begum AN, et al. Curcumin Inhibits Formation of Amyloid β Oligomers and Fibrils, Binds Plaques, and Reduces Amyloid in Vivo*. The Journal of Biological Chemistry. 2005;280(7):5892-901. Epub 2004 Dec 7