Impact of Fatty Acid Supplementation on Cognitive Performance among United States (US) Military Officers: The Ranger Resilience and Improved Performance on Phospholipid-Bound Omega-3’s (RRIPP-3) Study

This was a randomized, placebo-controlled trial in healthy young US Army officers enrolled in IBOLC and preparing for Ranger School, primarily male. In the omega-3 arm, 276 participants were randomized, 130 completed the study, and the as-per-protocol analysis included 133 experimental participants.

The active supplement was concentrated krill oil from Euphausia superba, providing approximately 2.3 g/day omega-3s with an EPA:DHA ratio of about 2:1. Participants in the omega-3 arm were instructed to consume 8 identical black gelatin capsules daily by mouth during IBOLC; supplementation was not given during the Ranger Course.

Krill oil omega-3 supplementation did not improve cognitive performance, resilience, or related mood outcomes versus placebo during military training. No statistically significant group-by-time interactions were found on any outcomes, including Connor-Davidson Resilience Scale (p = 0.7287), PROMIS Fatigue (p = 0.1281), PROMIS Sleep Related Impairment (p = 0.6878), and PROMIS Applied Cognition (p = 0.7789). Some outcomes worsened over time in both groups, but these changes were not attributable to the supplement. Fifteen adverse events were reported overall, 7 in the experimental group and 8 in the control group, and none were serious.

Retention was poor and compliance was questioned, which weakens confidence in the findings. The authors note the study may have been underpowered, so a true benefit cannot be ruled out. Results are also specific to a highly selected military training population and may not generalize well to other groups.