Previous research has linked curry consumption with a lower risk of Alzheimer's disease. Now, researchers may be closer to understanding why.
Curcumin, a component in curry and turmeric, is known for its anti-inflammatory and antioxidant properties. The spice, a staple in Indian diets, may help immune system cells called macrophages rid the body of amyloid beta, the protein that builds up to form damaging plaques in the brains of Alzheimer's patients.
"We know that macrophages aren't working property in Alzheimer's patients, since they seem to be defective in cleaning amyloid-beta from the brain," explains researcher Dr. Milan Fiala, a researcher with the David Geffen School of Medicine at UCLA and the VA Greater Los Angeles Health Care System. "We found that curcumin can help some macrophages to function properly in a test tube."
Next step: To determine if the popular spice works similarly in the human brain.
Earlier research by another UCLA team found that curcumin-fed mice with amyloid-beta plaques experienced a decrease in inflammation and reduced plaque formation.
In Fiala's study, blood samples were collected from six Alzheimer's patients and three healthy controls. Researchers then isolated macrophages and treated them with a curcumin solution for 24 hours, then added amyloid beta.
In three Alzheimer's patients, macrophages started ingesting the plaque-forming proteins after the curry was added.
This study is the latest by Fiala's team, which has examined the immune function of more than 100 Alzheimer's patients. 'Our research has helped to identify why the brain isn't being cleared of amyloid beta in Alzheimer's disease patients," he says. The immune system can attack and remove amyloid-beta from the brain, but the job is not done properly in Alzheimer's patients.'
Fiala says macrophages may be as important for Alzheimer's disease as insulin is for diabetes. if we can improve the immune system, we can help the body's natural ability to clear damaging plaques."
“In terms of treatment implications, it's very interesting that curcumin seems to help the brain clear away beta amyloid," notes Dr. Sam Gandy, chair of the medical and scientific advisory council at the Alzheimer's Association.
Fiala believes his team's research into the role of macrophages in Alzheimer's disease patients may one day point to new approaches for diagnosing and treating the illness.
Testing immune-cell response may also offer other researchers a novel way to assess the effectiveness of drugs in clearing amyloid beta from the brain. It might also help doctors individualize treatment, Fiala says.
Curcumin appears to have few side effects. "We can only say what we see in test tubes, but we don't see any toxic effects with curcumin, even administered in high doses," notes Fiala.
Curcumin's health benefits may extend beyond Alzheimer's disease. One recent six-month study, completed by researchers at Johns Hopkins University, finds that daily doses of the spice were associated with a nearly 60% lower risk for colon polyps, a known precursor to colon cancer.