Comparison between the AA/EPA ratio in depressed and non depressed elderly females: omega-3 fatty acid supplementation correlates with improved symptoms but does not change immunological parameters

Randomized placebo-controlled trial in depressed elderly female nursing-home residents in Pavia, Italy. For the omega-3 group, 22 participants aged 65 to 95 years (mean age 84.9±6.9 years) with DSM-IV depression were treated for 8 weeks; a healthy elderly comparison group was also used for AA/EPA status assessment.

For the omega-3 PUFA group, participants took one tablespoon orally once daily for 8 weeks, providing 2.5 g/day with an EPA:DHA ratio of 2:1. The product was given before lunch; the active comparison arm was placebo in the randomized trial.

Omega-3 supplementation improved depressive symptoms, but most immunological measures did not change meaningfully. In the omega-3 group, GDS decreased from 17.1±3.6 at baseline to 11.6±4.3 after 8 weeks, while whole-blood AA/EPA fell from 37.010 to 22.052 and RBC membrane AA/EPA fell from 77.878 to 42.291. CD16 increased from 13.0 (9.3) to 16.5 (10.8), whereas other immune markers were largely unchanged. The decline in AA/EPA ratio tracked symptom improvement, supporting its use as a marker of n-3 status.

The active arm was small and limited to elderly women in a single nursing-home setting, which reduces generalizability. Treatment duration was only 8 weeks, and the study did not show broad immunologic effects beyond a CD16 increase. Results are also constrained by reliance on pre/post changes within the active arm for several endpoints.