This spice really may be twice as nice. With radiant orange-yellow hues, its eye appeal is matched by its centuries-old versatility in Indian cuisine — a component of turmeric usually found in curry powder. Curcumin's prowess extends beyond the plate and the palate.
It packs a powerful punch of properties, including being anti-inflammatory, anticarcinogenic and antioxidant. A study has found curcumin might improve memory and attention in adults without dementia.
A January 2018 online issue of The American Journal of Geriatric Psychiatry presents the paper from a team of 16 authors. Gary W. Small, M.D., professor of psychiatry and biobehavioral sciences at the David Geffen School of Medicine at UCLA is lead author. He also directs both the UCLA Longevity Center and the geriatric psychiatry division of the Semel Institute for Neuroscience & Human Behavior.
The first of its kind
The research is the first long-term, double-blind placebo-controlled trial of a bioavailable form of curcumin, meaning it's easily absorbed into the bloodstream. Dr. Small and his team utilized twice-daily oral Theracurmin containing 90 mg of curcumin.
"We'd seen a study from Singapore including about 1,000 volunteers and those who ate Indian food often had better memory scores," he shared with HealthCentral in a telephone interview. "It prompted us to do this study. Despite our small sample size, there were effects that seemed to be very meaningful."
Out of a group of 259 potential participants, the researchers performed baseline cognitive assessments on 46 subjects, ages 50 to 90, who were determined to be aging normally or incurring mild cognitive impairment or MCI. All underwent a standardized cognitive assessment as the study began, again at 6 months, 12 months, and at 18 months, the study's conclusion. The curcumin group had improved memory and concentration up to 28 percent after 18 months, the authors say.
The power of curcumin
Adding that he doesn't know "exactly why curcumin works," Dr. Small hypothesizes it could be because the spice:
- Reduces inflammation, tied to Alzheimer's disease and major depression.
- Possesses antioxidant properties that stand up to oxidative stress that contributes to brain aging. Oxidative stress occurs when free radicals, the bad guys, outmaneuver antioxidants, the good guys. Free radicals can ignite certain harmful chemical reactions in our bodies.
- May counter negative effects of amyloid and tau in the brain — "sticky" abnormal proteins considered culprits in Alzheimer's disease.
His team wanted to evaluate participants using the most advanced technology. "That's why we used PET (positron emission tomography) scans before we started treatment, and after," says Dr. Small. "We saw significant effects in certain brain regions that control memory and mood. That evidence was consistent with our hypotheses but needs to be repeated."
He noted that because his study utilized a relatively small sample size, "it's important to be cautious with small studies and we'd like to do larger ones later. PET scans make that very expensive, however."
He's hopeful his result will prompt more research into curcumin. "One study doesn't prove the case," says Dr. Small. "They need to be replicated with larger samples, and that's one reason we publish them."
Earlier research conflicts
"Herbal treatments are not new, but rather centuries old," says Mustafa M. Husain, M.D., professor of psychiatry, neurology and medicine and chief of the geriatric psychiatry division at the University of Texas Southwestern Medical Center in Dallas. "There haven't been really well controlled trials of curcumin in the past or on a large scale or any real evidence it had a direct effect on the brain. Dr. Small's study was one of the first and it uses very highly sophisticated neuroimaging to look at biological markers and changes in the brain."
Although turmeric may not cure cognitive disorders, it may have a preventive effect as an antioxidant, he told HealthCentral in a telephone interview. The study is definitely a major initial step, he says.
Not everyone thinks curcumin has such potential, according to a review in the Journal of Medicinal Chemistry published in January 2017. The authors stated, upon publication, that:
"No double-blinded, placebo controlled clinical trial of curcumin has been successful. This manuscript (meaning this journal review and not Dr. Small's study) reviews the essential medicinal chemistry of curcumin and provides evidence that curcumin is an unstable, reactive, nonbioavailable compound and, therefore, a highly improbable lead."
In an email to HealthCentral, corresponding author Michael A. Walters said that: "We stand by the information we published in our review of the literature." Walters is a research associate professor of medicinal chemistry at the University of Minnesota. However, that review of controlled studies was published a year before these new results were available.
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