Dietary and not-dietary determinants associated with changes in red blood cell omega-3-essential fatty acids and serum lutein status in a selected adult population

Objectives: The role of omega-3-essential fatty acids (EFA) in addition to lutein and zeaxanthin in preventing age-related macular degeneration remains unclear. This study assessed factors (dietary and non-dietary) associated with changes in red blood cell membrane (RBCM) omega-3 and serum lutein (L) status in a selected adult population. Methods: A cross-sectional study was conducted among 33 healthy adults aged 19-29 and 30-52 years. Background (online self-administered) and dietary (Cancer Council's dietary questionnaire) information were obtained. Serum L and RBCM omega-3 status were determined using HPLC and GC-MS. Determinants associated with changes in RBCM omega-3 and serum L status were established using multiple regression, Pearson's, and Spearman's correlation. Results: Mean RBCM omega-3-EFA and EPA/AA ratio were 9.08 ± 4.09% and 0.09 ± 0.03% respectively. Sixty % of study participants had normal RBCM omega-3-EFA status. Men consumed more omega-3-EFA rich sources in their diet than women (10.06 ± 5.02% vs 6.89 ± 2.02%) (p = 0.02). Participants aged 30-52 years had higher but not significant mean RBCM omega-3-EFA levels compared to those aged 19-29 years (8.64 ± 3.58% vs 8.02 ± 4.38%). Canola oil and other seafoods (excluding fish) were the major rich sources of omega-3-EFA which showed an association with participants' educational status (p = 0.01). Longer residency status (>10 years) was associated with dietary intakes of omega-3-EFA and reflected in most participants achieving the required omega-3-status (p = 0.04). RBCM omega-3-EFA correlated (r = -0.37, p = 0.04) with dietary lutein (L) + zeaxanthin (Z) and other seafoods (r = 0.43, p = 0.01). Other seafoods and EPA/AA ratio were responsible for observed changes in serum L. Conclusions: Other seafoods, levels of EPA/AA ratio and longer residency status can positively influence changes in omega-3 and serum L status among healthy Australian adults at risk of AMD.