With more and more of the aging population affected by Alzheimer’s disease, and clinical trials for new medications often providing underwhelming results, a new study in The American Journal of Geriatric Psychiatry may be especially promising. It finds that taking a daily dose of curcumin, the compound in turmeric root that gives curry its yellow color, may not only prevent memory problems from worsening over time, but actually improve them. And perhaps most noteworthy, these changes were seen not only in the participants’ cognitive capacities, but also in their brain cells.
The team, led by UCLA’s Gary Small, randomized 40 people between the ages of 50 and 90 to take a twice-daily 90-mg curcumin supplement or placebo for 18 months.The curcumin supplements were a preparation that have greater bioavailability than usual, meaning it’s more readily absorbed and used by the body. The participants all had mild memory problems, but didn’t have Alzheimer’s disease or other form of dementia. At the study’s outset, they took tests of memory and cognition, filled out questionnaires to measure mood and depression, and underwent brain scans so the team could look at deposition of “brain gunk”—amyloid-beta plaques and tau “tangles,” the two hallmarks of Alzheimer’s.
Every six months over the study’s 18 month period, the team tested the participants for memory, cognition, and mood; they also scanned their brains. (The study was double-blind, so even the researchers didn’t know what supplement the participants had been assigned till after the study was over.)
It turned out that the memory function of those who’d taken curcumin improved by 28% on average over the 18 months. In contrast, the control group’s scores rose slightly (possibly because they got more familiar with the tests) and then declined. The depression scores of those taking curcumin also improved; the control group’s didn’t change. And interestingly, brain scans revealed significantly less amyloid and tau accumulation in two brain regions of the participants taking curcumin—the amygdala and hypothalamus, which control anxiety, memory, decision-making, and emotion.
The main side-effects in the current study were abdominal pain and nausea.
The new study is exciting, since it’s a true clinical study, and earlier evidence regarding the therapeutic effects of curcumin has been mixed. Researchers have long observed that some groups of people in India have lower incidence of Alzheimer’s disease, which is thought to be due in part to the higher intake of turmeric. Studies have also hinted at curcumin’s antidepressant and anti-anxiety effects, while others have illustrated its potential role in preserving brain function as we age. Curcumin’s antioxidant and anti-inflammatory effects are thought to underlie its neurological effects: It’s been shown to disrupt the formation of, and even help break down, the amyloid plaques that build up in the brains of Alzheimer’s patients. Still, other researchers don’t believe it has much of an effect, or that curcumin is the right component of turmeric to focus on.
“Exactly how curcumin exerts its effects is not certain, but it may be due to its ability to reduce brain inﬂammation, which has been linked to both Alzheimer’s disease and major depression,” said Small in a statement. The team next plans to look at whether the supplement may be effective in treating people with major depression rather than memory problems.
The study’s main limitation is that it was quite small and its participants were generally healthy, educated, and motivated to complete the long trial. So whether or not the results are applicable to the general population is a little unclear; follow-up studies will need to take this into account.