Association between Obesity and Omega-3 Status in Healthy Young Women.

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are essential for healthy development and protect against metabolic disease. However, individuals with obesity may be pre-disposed to experiencing lower n-3 PUFA status than normal-weight individuals. This cross-sectional study examined the relationship between the omega-3 index (O3I), body mass index (BMI) and dietary intake in healthy young women (n = 300; age = 18-35 y), a group not previously focused on. Intake was adjusted for energy using the residuals method, and associations were explored using independent t-tests and Pearson's correlations. Participants with obesity were found to have significantly lower O3I than normal-weight participants (p < 0.0001); however, no significant differences were observed in mean n-3 PUFA intakes. Even so, energy-adjusted intakes of n-3 PUFAs, with the exception of alpha-linolenic acid, were significantly correlated with O3I. This study demonstrates that O3I is influenced by both BMI and diet in young women; however the relationship between these two variables may be complex. Current intakes of n-3 PUFA observed in young women may not be effective in achieving target O3I levels in those with obesity, and further research is needed to find effective ways of improving n-3 PUFA status in a group already at increased risk of metabolic disease.

Omega-3 polyunsaturated fatty acids status and cognitive function in young women.

BACKGROUND: Research indicates that low omega-3 polyunsaturated fatty acid (n-3 PUFA) may be associated with decreased cognitive function. This study examined the association between n-3 PUFA status and cognitive function in young Australian women. METHODS: This was a secondary outcome analysis of a cross-sectional study that recruited 300 healthy women (18-35 y) of normal weight (NW: BMI 18.5-24.9 kg/m2) or obese weight (OB: BMI ≥30.0 kg/m2). Participants completed a computer-based cognition testing battery (IntegNeuro™) evaluating the domains of impulsivity, attention, information processing, memory and executive function. The Omega-3 Index (O3I) was used to determine n-3 PUFA status (percentage of EPA (20:5n-3) plus DHA (22:6n3) in the red cell membrane) and the participants were divided into O3I tertile groups: T1 < 5.47%, T2 = 5.47-6.75%, T3 > 6.75%. Potential confounding factors of BMI, inflammatory status (C-reactive Protein), physical activity (total MET-min/wk), alpha1-acid glycoprotein, serum ferritin and hemoglobin, were assessed. Data reported as z-scores (mean ± SD), analyses via ANOVA and ANCOVA. RESULTS: Two hundred ninety-nine women (26.9 ± 5.4 y) completed the study (O3I data, n = 288). The ANOVA showed no overall group differences but a significant group × cognition domain interaction (p < 0.01). Post hoc tests showed that participants in the low O3I tertile group scored significantly lower on attention than the middle group (p = 0.01; ES = 0.45 [0.15-0.74]), while the difference with the high group was borderline significant (p = 0.052; ES = 0.38 [0.09-0.68]). After confounder adjustments, the low group had lower attention scores than both the middle (p = 0.01) and high (p = 0.048) groups. These findings were supported by univariate analyses which found significant group differences for the attention domain only (p = 0.004). CONCLUSIONS: Cognitive function in the attention domain was lower in women with lower O3I, but still within normal range. This reduced but normal level of cognition potentially provides a lower baseline from which cognition would decline with age. Further investigation of individuals with low n-3 PUFA status is warranted.