The article by Davinelli et al. appearing in Antioxidants (2021) questioned the effects of carotenoid supplementation on cognitive functioning and risk for cognitive decline. This meta-analysis contains a review of 9 randomized controlled trials with an aggregate of 4,402 non-demented participants aged 45 to 78 years.

Can Carotenoids Boost Brain Health? A Meta-Analysis of Clinical Trials?

Interesting News . Apr 02, 2025

The article by Davinelli et al. appearing in Antioxidants (2021) questioned the effects of carotenoid supplementation on cognitive functioning and risk for cognitive decline. This meta-analysis contains a review of 9 randomized controlled trials with an aggregate of 4,402 non-demented participants aged 45 to 78 years.

Key Findings

Carotenoid supplementation improved cognitive performance significantly with a small positive effect size (Hedge’s g=0.14; p<0.0001).
There were no signs of inconsistency and/or publication bias in the studies, which further strengthens the findings.
Carotenoids can promote neuroprotection and cognitive health due to their antioxidant properties.

Final Judgment: The Role of Carotenoids in Brain Function?

The present analysis suggests that carotenoid supplementation should thus be considered in the preservation of cognitive functions or reducing possibilities for impairment. Findings were quite conclusive regarding carotenoids possibly playing a role in brain health, but the effect size was small.

Level of Evidence for Carotenoids and Cognitive Function

This meta-analysis of randomized controlled trials (RCTs) represents a strong to moderate level of evidence in the hierarchy of evidence-based medicine. So, here it is ranked:

Study Design & Evidence Strength

The study included:

Nine randomized controlled trials (RCTs) → Level 1B (high-quality individual RCTs).
Meta-analysis of RCTs → Level 1A (strongest evidence level).

Indeed, it is because meta-analyses of RCTs provide the strongest evidence possible that, despite an almost negligible effect size, the conclusions of this study are most solid within scientific credibility. But while carotenoids maybe part of the larger picture, they are not a sole fix for cognitive health.

Last Examination of Evidence

Strength: The high rating was based on the meta-analysis of RCTs.

Limitation: A small effect size also calls for additional long-term studies.

Need for Further Research: Long-term studies of larger scale will be needed to confirm optimal dosage and real-world effects.

Future Steps:

To confirm optimal dosages, mechanisms, and long-term effects, more such long-term studies would be necessary. Incorporating carotenoid-rich foods such as carrots, spinach, and tomatoes into one’s diet may offer cognitive benefit as part of a healthy lifestyle.