Promising benefits of six-month Phaeodactylum tricornutum microalgae supplementation on cognitive function and inflammation in healthy older adults with age-associated memory impairment

Emily Goodbody¹Jonathan Maury²Andrea Doolan¹Gillian DunnGalvin^1*Charles Kakilla¹Rémi Pradelles²Timothy Dinan^1,3

• ¹Atlantia Clinical Trials, Cork, Ireland
• ²Microphyt, Baillargues, France
• ³APC Microbiome Institute, College of Medicine and Health, University College Cork, Cork, Ireland

Introduction: Cognitive decline is a major concern in aging. Microalgae, rich in bioactive compounds, offer a natural dietary approach to support brain health. In aging mice, a microalgae extract from Phaeodactylum tricornutum (Pt), containing fucoxanthin, improved learning, memory, and reduced brain inflammation and oxidative stress. This double-blind, randomized controlled study aimed to evaluate the effects of Pt extract supplementation on cognitive function, mood, stress, and inflammation in older adults over 24 weeks.Methods: Sixty-six adults (55-75 years) with age-associated memory impairment (AAMI) were randomly assigned to receive either a placebo (maltodextrin) or 550 mg Pt extract (containing 4.4 mg fucoxanthin, PUFAs, and saturated fatty acids). Participants completed the COMPASS cognitive test battery to assess memory, attention, vigilance, and executive function. Sleep quality, mood, stress, and inflammatory markers were also measured at baseline, 12, and 24 weeks.Results: No significant between-group differences were found in primary cognitive outcomes. However, posthoc analysis revealed improvements in Stroop task reaction time (p=0.005, d=0.81) and delayed word recall (p=0.010, d=0.53) within the Pt group at 24 weeks, while no changes occurred in the placebo group. Perceived stress (PSS Total Score) significantly decreased in the Pt group (p=0.04, d=0.41). Additionally, blood hs-CRP levels, an aging-related inflammation marker, declined significantly from 3.9 mg/L to 2.1 mg/L in the Pt group (p=0.002, d=0.84), indicating a large effect size. No adverse effects or safety concerns were observed.Discussion: This study suggests that daily Pt extract supplementation, providing 4.4 mg of fucoxanthin, may enhance cognitive function (executive function, attention, episodic memory) and reduce inflammation in older adults with AAMI. While results are promising, a larger-scale trial is needed to confirm these findings and explore long-term benefits in preventing cognitive decline.