Habitual Oily Fish Intake and Microvascular Integrity in Frequent Fish Consumers: A Population-Based, Cross-Sectional Pilot Study.

ObjectivesMicrovascular health is increasingly recognized as a determinant of functional aging and cardiometabolic risk in aging populations. Marine omega-3 polyunsaturated fatty acids (ω-3 PUFAs), primarily obtained from oily fish, have endothelial-stabilizing and anti-inflammatory properties that may preserve microvascular structure. This pilot cross-sectional study evaluated whether habitual oily fish intake - a modifiable dietary behavior relevant to primary care and public health - is associated with microvascular integrity in older adults.MethodsIn this community-based study, 306 older adults underwent high-resolution nailfold capillaroscopy (NFC). Images were analyzed using AI-assisted quantification with expert validation to assess capillary morphology and density. Dietary exposure was estimated from five consecutive annual surveys to capture habitual oily fish intake patterns. Multivariable linear models adjusted for demographics and cardiovascular risk factors examined associations between tertiles of oily fish intake and NFC parameters.ResultsHigher oily fish intake was independently associated with fewer tortuous capillaries (β: -1.74; 95% CI: -2.01 to -0.74), fewer dilated capillaries (β: -2.69; 95% CI: -5.27 to -0.11), and greater capillary density (β: 0.43; 95% CI: 0.07 to 0.78). Associations remained robust after adjustment for lifestyle and vascular risk factors.ConclusionSustained consumption of oily fish was associated with fewer structural microvascular abnormalities. Given the pilot nature of this study, these hypothesis-generating findings will guide a planned longitudinal follow-up to determine whether oily fish intake influences the progression of microvascular damage. Insights from this work may help shape dietary counseling strategies in primary care aimed at supporting microvascular health in older adults.