Researchers at Japanese health food and functional beverage company House Wellness Foods Corp. evaluated the effect of CLE on cognitive scores in healthy participants with subtle cognitive weaknesses.
The data from the RCT found that compared to placebo, the supplement significantly improved scores relating to orientation and attention.
Orientation is a fundamental cognitive function necessary for daily functioning, and impairments can often appear as early symptoms of mild cognitive impairment (MCI). Impairments in attention can affect communication and daily life, and appear early in the course of dementia.
“Because orientation and attention are among the cognitive domains affected early in dementia, improvements in these functions may have broader implications,” the researchers wrote. “Although this study did not directly assess clinical outcomes such as MCI or dementia incidence, the observed improvements raise the possibility that CLE may reduce risk for these disorders.”
Preserving cognitive function
Cognitive function declines with aging and with factors such as inflammation, affecting verbal and visual memory, attention, and executive functions. These alterations can start as early as the twenties and may progress through MCI, developing into dementia.
Preserving cognitive function and preventing dementia is a public health priority, although no proven and effective prevention methods or treatments exist.
Chronic low-grade inflammation has been observed as a key driver of cognitive decline, so strategies to address this are of interest. Reducing risk factors by improving diet and lifestyle has attracted attention, and food-derived bioactive compounds such as curcumin in turmeric have demonstrated promising results.
Curcumin has potent antioxidant and anti-inflammatory properties that may protect the brain from oxidative stress and neuroinflammation.
Recent studies have suggested that factors such as dosage, duration of supplementation, bioavailability, and genetics influence how effective curcumin is for cognitive preservation.
In addition, the current researchers note that “curcumin-free C. longa water extracts have been reported to exhibit diverse biological activities”.
The non-curcuminoid compounds within the extract used in the present study are sesquiterpenoids turmeronols A and B and bisacurone, and these compounds are captured by the dual extraction method used by the suppliers.
The study notes that the synergy of these compounds may suppress inflammatory pathways and mediators that operate independently of standard curcumin by targeting microglial activation in the brain.
Study details
The randomized, double-blind, placebo-controlled trial involved 40 healthy Japanese participants aged 40 to 69 years with subtle cognitive weaknesses within the normal range. They were divided into two groups that took two daily capsules of Curcuma longa extract (CLE) or placebo for 24 weeks.
The CLE capsules, supplied by House Wellness Foods, contained a mixture of hot water extract and supercritical carbon dioxide extract of C. longa and contained active ingredients, turmeronols A and B, and bisacurone.
A physician interview, physical assessments, and a cognitive evaluation of the participants were conducted at the start, halfway through, and at the end of the study.
Cognitrax technology was used to measure neurocognitive status, and the results showed no difference between groups.
Using the MoCA-J score, the Japanese version of the Montreal Cognitive Assessment, the researchers found that orientation scores were significantly higher in the CLE group than in the placebo group, but other MoCA-J scores did not differ.
Eye-tracking cognitive assessment showed significantly higher attention and orientation scores (in 35 cognitive endpoints for orientation) in the CLE group at 24 weeks, and no differences in other cognitive scores.
Safety assessments using blood and urine samples showed no differences between groups, and no adverse effects were reported.
The researchers acknowledged the study limitations, noting that the findings may not generalize to the broader population of middle-aged and older adults. They recommended that the anti-inflammatory properties and mechanisms involved be explored in future research.
Source: Front. Nutr., https://doi.org/10.3389/fnut.2026.1866285, “Effects of Curcuma longa extract on cognitive function in healthy participants with subtle cognitive weaknesses within the normal range: a randomized, double-blind, placebo-controlled trial.” Authors: R. Saji et al.
