The results were presented in a new Australian RCT, which revealed benefits for volunteers within the supplementation group when testing for visual episodic memory and visual learning.
However, several other cognitive-related tests failed to show significant improvements in computer-based measures or self-report measures of cognition, memory, mood or physical function.
The half-year trial, conducted by researchers from Perth, Australia, featured 90 individuals aged between 40 and 75 years old who received lutein and zeaxanthin or a placebo daily over 180 days.
The volunteers, who had self-reported cognitive complaints such as memory and attention issues, were recruited through social media and email databases between February and March 2021. Excluded from the trial were people with chronic diseases and disorders such as CVD, high blood pressure, Type One diabetes and renal failure.
For this study, the researchers used active ingredients supplied by Bio-gen Extracts, which contained 10 mg of lutein and 2 mg of zeaxanthin in sunflower oil.
Results were measured in five ways: the primary outcome measure being the Computerised Mental Performance Assessment System (COMPASS) and secondary outcome measures such as the Behaviour Rating Inventory of Executive Function – Adult Version (BRIEF-A); and questionnaires named Profile of Mood States, Abbreviated Version (POMS-A), Patient-Reported Outcomes Measurement Information System-29 (PROMIS-29) and Cognitive Failures Questionnaire (CFQ).
Analysis from the COMPASS measurement showed a significant increase of abilities, such as episodic memory, word recall, delayed word recall, location learning recall, word recognition and picture recognition, in the lutein/zeaxanthin group. A slower reaction time was detected in the numeric working memory ability of the placebo group.
The secondary measurements showed statistically-significant reductions in the total CFQ and BRIEF-A index scores, which evaluate behavioural regulation and metacognition index, for both the lutein/zeaxanthin and placebo groups.
The lutein/zeaxanthin group tolerated the supplements well, with no reports of significant adverse effects in 77% of the participants.
The group was also noted to be consistently performing better at each trial.
As such, results from the trial suggest that supplementation with lutein and zeaxanthin may improve visual memory and learning in people aged 40 to 75 years old, and when delivered over a shorter treatment duration (six months) than previous trials (around 12 months).
The effects of lutein and zeaxanthin on visual memory and performance may have important implications for preventing cognitive decline, because a relationship between visual memory and cognitive decline has been identified.
The researchers hypothesised that lutein and zeaxanthin provided benefits due to their antioxidant and anti-inflammatory properties, but the precise mechanism by which they improve memory requires further investigation as the study.
The researchers concluded: “In summary, the results from this study suggest that supplementation with lutein and zeaxanthin for 6 months in community-dwelling adults with self-reported cognitive complaints is associated with improvements in visual memory and learning.
“However, the treatment had no other effect on other computer-based measures of cognitive performance or self-report measures of cognition, memory, mood, or physical function. Further trials will be essential to clarify the potential benefits of lutein and zeaxanthin supplementation in diverse populations over varying intervention periods, and utilising additional measures of change in cognitive performance and neurological activity over time".
Bio-gen Extracts Pvt funded the study but was not involved in the trial or writing process.
Source: Frontiers in Nutrition
“The Effects of Lutein and Zeaxanthin Supplementation on Cognitive Function in Adults with Self-Reported Mild Cognitive Complaints: A Randomized, Double-Blind, Placebo-Controlled Study”
Authors: Adrian L. Lopresti, et al