Endothelial dysfunction (dysfunction of the endothelium, or the inner lining of the arteries), involves damage to the artery lining that triggers inflammation and the development of lesions characteristic of atherosclerosis, the accumulation of plaque buildup in the arteries. Endothelial dysfunction (ED) occurs very early and throughout the atherosclerotic process.

ED indicates an imbalance between endothelial damage and repair, which can be measured using two biomarkers: endothelial progenitor cells (EPCs) and endothelial microparticles (EMPs). EPCs are immature precursor cells that reflect artery repair and EMPs are small vesicles released from activated or damaged endothelial cells and reflect artery damage. EMPs are higher in individuals with metabolic syndrome, hypertension, and obesity, and lower amounts of EPCs are associated with cardiovascular risk factors.1,2,3

In a recent study published in the American Journal of Clinical Nutrition, researchers discovered that individuals with moderate cardiovascular risk who supplemented with 1.5 g of omega-3 EPA (900 mg) plus DHA (600 mg) or placebo for eight weeks had higher amounts of EPCs and lower amounts of EMPs, suggesting an increased ability for endothelial repair and protection against artery damage.

While vascular function tests did not show improvement nor was there an effect on circulating concentrations of nitric oxide or inflammatory markers, more studies are needed to replicate the study and to determine optimal dosage and length of treatment. Additionally, individuals at higher risk for cardiovascular disease who might show a stronger vascular response should be studied. And, as I always mention, testing red blood cell membrane levels of omega-3 fatty acids is imperative when studying omega-3s to determine how much the omega-3 fats are increased within the body’s tissues, where they are needed.

Previous studies have found a beneficial effect of omega-3s on endothelial function.4,5 This current study helps explain just how these beneficial effects might occur, and helps to strengthen the evidence that omega-3 fats are crucial for heart health.


  1. Nozaki T, Suqiyama S, Koga H, et al., “Significance of a multiple biomarkers strategy including endothelial dysfunction to improve risk stratification for cardiovascular events in patients at high risk for coronary heart disease.” J Am Coll Cardiol. 2009 Aug 11;54(7):601-8.
  2. Kunz GA, Liang G, Cuculi F, et al., “Circulating endothelial progenitor cells predict coronary artery disease severity.” Am Heart J. 2006 Jul;152(1):190-5.
  3. Werner N, Kosiol S, Schiegl T, et al., “Circulating endothelial progenitor cells and cardiovascular outcomes.” N Engl J Med. 2005 Sep 8;353(10):999-1007.
  4. Egert S and Stehle P, “Impact of n-3 fatty acids on endothelial function: results from human interventions studies.” Curr Opin Clin Nutr Metab Care. 2011 Mar;14(2):121-31.
  5. Wang Q, Liang X, Wang L, et al., “Effect of omega-3 fatty acids supplementation on endothelial function: a meta-analysis of randomized controlled trials.” Atherosclerosis. 2012 Apr;221(2):536-43.