Lutein and Zeaxanthin Influence Brain Function in Older Adults: A Randomized Controlled Trial

Area of Science:

• Neuroscience
• Cognitive Science
• Nutritional Science

Background:

• Cognitive decline is a significant concern in aging populations.
• Lutein (L) and zeaxanthin (Z) are carotenoids found in fruits and vegetables, known for their roles in eye health.
• Their potential impact on brain function, particularly in older adults, warrants investigation.

Purpose of the Study:

• To investigate the effects of lutein (L) and zeaxanthin (Z) supplementation on brain function and cognitive performance in older adults.
• To utilize functional magnetic resonance imaging (fMRI) to assess neural efficiency during a verbal learning task.
• To determine if L and Z supplementation can buffer age-related cognitive decline.

Main Methods:

• A randomized controlled trial involving 44 older adults (mean age=72 years).
• Participants received either placebo or L+Z supplementation (12 mg/daily) for 1 year.
• Neurocognitive performance and fMRI-assessed blood-oxygen-level-dependent (BOLD) signal were measured at baseline and post-intervention during a verbal learning task.

Main Results:

• Lutein and zeaxanthin supplementation appeared to buffer cognitive decline on the verbal learning task (Cohen's d=.84).
• Significant interactions were observed in the left dorsolateral prefrontal cortex and anterior cingulate cortex during learning, showing increased BOLD signal in the supplement group.
• While not significant during recall, within-group contrasts showed increased left prefrontal activation in the supplement group.

Conclusions:

• Lutein (L) and zeaxanthin (Z) supplementation may benefit neurocognitive function in older adults.
• The findings suggest enhanced cerebral perfusion as a potential mechanism.
• Supplementation, even for a discrete period in late life, may positively impact brain health.