Relationship Between Distance Run Per Week, Omega-3 Index, and Arachidonic Acid (AA)/Eicosapentaenoic Acid (EPA) Ratio: An Observational Retrospective Study in Non-elite Runners

Abstract

Background: Tissue availability of polyunsaturated fatty acids (PUFA) depends on several factors, including dietary intake, physical exercise, genetic variation, and metabolic turnover. However, there is limited evidence whether running training activity per se may influence indices associated with PUFA metabolism such as Omega-3 (ω-3) index and arachidonic acid (AA; 20:4ω-6)/eicosapentaenoic acid (EPA; 20:5ω-3) ratio. Objective: To examine the association between kilometers (Km) run per week and changes in ω-3 index and AA/EPA ratio. Methods: We conducted a retrospective, observational, cohort study of 257 non-elite runners (mean age: 40.85 ± 12.17 years) who consumed no fatty acid supplements and provided a blood sample for analysis. The whole blood samples were collected by finger sticks, stored on absorbent filter paper, and then PUFA were quantified by gas chromatography (GC) and ω-3 index and AA/EPA ratio measured. Results: In a multivariate linear regression model, a gradual decrease of the ω-3 index was observed with higher weekly running distance (β = −0.033; 95% CI −0.039 to −0.026; R 2 = 0.447; p < 0.0001). We also found a progressive increase of the AA/EPA ratio in subjects who ran greater weekly distances (β = 0.092; 95% CI 0.038 to 0.146; R 2 = 0.320; p = 0.001). No other significant associations were observed with other variables, including years of running training and weekly training frequency (hours/week). Finally, as expected, a significant inverse correlation between ω-3 index and AA/EPA ratio (β = −2.614; 95% CI −3.407 to −1.821; R 2 = 0.336; p < 0.0001) was detected. Conclusions: These findings suggest that distance running training and its weekly volume may negatively contribute to changes of the ω-3 index and AA/EPA ratio. Further studies with greater sample size will be required to replicate and extend these data.

Dietary and Biological Assessment of the Omega-3 Status of Collegiate Athletes: A Cross-Sectional Analysis

“…Although the majority of collegiate athletes participating in the present study did not meet current dietary ω-3 FA recommendations-similar to previous observations [39]-these guidelines are not specific to athletes. Further research is needed to establish athlete-specific recommendations, taking into consideration the physiological implications of advanced levels of training on metabolism and the inflammatory response [51][52][53]. For example, lower average O3i was observed among non-elite runners with greater training mileage compared to those with lesser running mileage [51].…”

“…Further research is needed to establish athlete-specific recommendations, taking into consideration the physiological implications of advanced levels of training on metabolism and the inflammatory response [51][52][53]. For example, lower average O3i was observed among non-elite runners with greater training mileage compared to those with lesser running mileage [51]. Additional research is also needed to identify intake of ω-3 FA most effective for neuroprotection and brain health.…”

Omega-3 index in 2018/19

“…More recently, similar data were found in 404 US national division I college football athletes with a mean omega-3 index of 4⋅4 ( sd 0⋅8) %, again only one athlete in the target range (49) . Interestingly, the more energy was burned throughout the season, the lower the omega-3 index became (50) . This has important implications for athletes, since a low omega-3 index predisposes to delayed-onset muscle soreness, and increasing the omega-3 index results in less creatine kinase release from muscle, less inflammatory reaction (measured as muscle swelling and pro-inflammatory cytokines in plasma) and less loss of function (51,52) .…”

Dietary and Biological Assessment of Omega-3 Status of Collegiate Athletes: A Cross-Sectional Analysis

“…Further research is needed to establish athlete-specific recommendations, especially taking into consideration the physiological implications of advanced levels of training on metabolism and the inflammatory response. (48–50) For example, lower average O3i was observed among non-elite runners with greater training mileage compared to those with lesser running mileage. (48)…”

“…(48–50) For example, lower average O3i was observed among non-elite runners with greater training mileage compared to those with lesser running mileage. (48)…”