Dietary intake of α-linolenic acid and risk of age-related macular degeneration ,

Abstract

Background:The relation between a-linolenic acid (ALA), a plant-derived omega-3 (n-3) fatty acid, and age-related macular degeneration (AMD) is unclear. European researchers reported that #40% of ALA can be present as trans forms. Objective: We aimed to evaluate the associations between intake of ALA and intermediate and advanced AMD. Design: Seventy-five thousand eight hundred eighty-nine women from the Nurses' Health Study and 38,961 men from Health Professionals Follow-Up Study were followed up from 1984 to 2012 and from 1986 to 2010, respectively. We assessed dietary intake by a validated food-frequency questionnaire at baseline and every 4 y thereafter. One thousand five hundred eighty-nine incident intermediate and 1356 advanced AMD cases (primarily neovascular AMD) were confirmed by medical record review. Results: The multivariable-adjusted HR for intermediate AMD comparing ALA intake at the top quintile to the bottom quintile was 1.28 (95% CI: 1.05, 1.56; P-trend = 0.01) in the analyses combining 2 cohorts. The HR in each cohort was in the positive direction but reached statistical significance only in the women. However, the positive association was apparent only in the pre-2002 era in each cohort and not afterward (P-time interaction = 0.003). ALA intake was not associated with advanced AMD in either time period. Using gasliquid chromatography, we identified both cis ALA (mean 6 SD: 0.13% 6 0.04%) and trans ALA isomers (0.05% 6 0.01%) in 395 erythrocyte samples collected in [1989][1990]. In stepwise regression models, mayonnaise was the leading predictor of erythrocyte concentrations of cis ALA and one isomer of trans ALA. We also found trans ALA in mayonnaise samples. Conclusions: A high intake of ALA was associated with an increased risk of intermediate AMD before 2002 but not afterward. The period before 2002 coincides with the same time period when trans ALA was found in food and participants' blood; this finding deserves further study.Am J Clin Nutr 2017;105:1483-92.

Risk factors for progression of age‐related macular degeneration

“…Table shows an overview of different kinds of systemic lipid factors and their association with the development of early and late AMD, as identified in prospective cohort studies. Of note, most prospective studies investigating fatty acids have estimated the systemic levels based on food frequency questionnaires and only a minority of the studies have measured systemic blood levels …”

“…Whether increased dietary intake or higher systemic levels of ALA are associated AMD progression is not clear. Three longitudinal population studies showed no association between a higher dietary intake of ALA and AMD progression, and three prospective studies on systemic ALA levels reported conflicting results: one study showed that higher plasma ALA levels were associated with a decreased risk of developing GA and nAMD, while two other studies showed an increased risk of developing early and late AMD …”

“…Of note, most prospective studies investigating fatty acids have estimated the systemic levels based on food frequency questionnaires and only a minority of the studies have measured systemic blood levels. 127,[221][222][223][224]…”

“…Three longitudinal population studies showed no association between a higher dietary intake of ALA and AMD progression, 124,126,226 and three prospective studies on systemic ALA levels reported conflicting results: one study showed that higher plasma ALA levels were associated with a decreased risk of developing GA and nAMD, 221 while two other studies showed an increased risk of developing early and late AMD. 123,224 Several longitudinal studies have investigated dietary intake and systemic levels of EPA and DHA in AMD. Half of these studies found a decreased risk of developing early or late AMD in patients consuming higher amounts of EPA, 202,203,228 and the majority of longitudinal studies reported a decreased risk of developing early or late AMD when consuming higher amounts of DHA.…”

<p>The cGAS/STING pathway: a sensor of senescence-associated DNA damage and trigger of inflammation in early age-related macular degeneration</p>

“…Several clinical trials have focused on the prevention of AMD progression, and the data from Age-Related Eye Disease Study 2 (AREDS2) showed that AREDS formulation in primary analyses did not further reduce the risk of progression to advanced AMD 19. Additionally, several epidemiological studies and meta-analyses demonstrated that omega-3 fatty intake was associated with a lower risk of AMD; however, the conclusion should be validated by more well-designed clinical studies 20,21. Clinical application of nutrition supplementation for the treatment of early AMD is still far from being a reality.…”