Changes in erythrocyte fatty acid profile after 12 weeks of omega-3 fatty acid (EPA+DHA) supplementation and endurance training in amateur runners.

N-3 PUFA supplementation for 12 weeks significantly increased EPA, docosapentaenoic acid, DHA, and total PUFAs in red blood cells compared to the placebo group.

• The supplementation group received 2234 mg of EPA and 916 mg of DHA daily for 12 weeks.
• The study included 26 amateur runners: 14 in the n-3 PUFA supplementation group and 12 in the placebo group.
• Both groups underwent the same exercise training intervention.
• Changes were statistically significant compared to the placebo group.

N-3 PUFA supplementation significantly decreased multiple saturated, monounsaturated, and omega-6 fatty acids in red blood cells.

• Significant decreases were observed in lignoceric acid, palmitoleic acid, vaccenic acid, gondoic acid, linoleic acid, eicosadienoic acid, dihomo-γ-linolenic acid, and arachidonic acid.
• A decrease in total monounsaturated fatty acids (MUFAs) was also observed.
• The AA/EPA ratio decreased significantly in the supplementation group compared to placebo.
• All changes were relative to the placebo group after the 12-week intervention.

N-3 PUFA supplementation increased the omega-3 index, delta 9-desaturase index (C16), and PUFA/MUFA index in red blood cells.

• Increases in omega-3 index were statistically significant compared to the placebo group.
• The delta 9-desaturase index (C16) increased after supplementation.
• The PUFA/MUFA ratio increased following 12 weeks of n-3 PUFA supplementation.
• These index changes reflect the broader shift in erythrocyte fatty acid composition.

Exercise training alone had no effect on red blood cell fatty acid profiles.

• No statistically significant changes in RBC fatty acids were observed in the placebo group after 12 weeks.
• Both the supplementation and placebo groups underwent the same endurance training intervention.
• The absence of change in the placebo group isolates the supplementation effect from the training effect.
• This finding indicates that the observed FA profile changes were attributable to n-3 PUFA supplementation rather than exercise.

Red blood cell fatty acid profiles reflect average FA concentrations over 3-4 months and are not susceptible to daily dietary fluctuations.

• RBC FA profiles show average fatty acid concentrations over the past 3-4 months.
• Unlike plasma FA profiles, RBC profiles are not susceptible to daily fluctuations dependent on diet or supplementation.
• This characteristic makes RBCs a more stable biomarker for long-term fatty acid status assessment.
• The authors chose RBC FA profiling as a more reliable measure than plasma for assessing the effects of 12-week supplementation.