Lead study author Dr. Haiyan Tong, MD, PhD, a research biologist with the United States Environmental Protection Agency, said exposure to airborne particulate matter can lead to endothelial dysfunction, a condition in which the endothelium (inner lining) of blood vessels does not function normally, which is a risk factor for clinical cardiovascular events and progression of atherosclerosis.
She said as olive oil and fish oil are known to have beneficial effects on endothelial dysfunction, they examined whether use of these supplements would counteract the adverse cardiovascular effects of exposure to concentrated ambient particulate matter in a controlled setting.
The study involved 42 healthy adults who were randomized to receive either 3 gram/day of olive oil, fish oil, or no supplements for 4 weeks before undergoing controlled 2-hour exposures to filtered air, followed on the next day by exposure to fine/ultrafine concentrated ambient particulate matter (CAP, mean mass concentration 253 + - 16 micro g/m3) in a controlled-exposure chamber.
Endothelial function was assessed by sonographic measurement of flow-mediated dilation of the brachial artery before, immediately after, and 20 hours after exposure to air and CAP. Blood markers of vasoconstriction and fibrinolysis (a body process that keeps blood clots from growing) were also measured.
Immediately after exposure to CAP, significant particulate matter mass-dependent reductions in flow-mediated dilation were observed in the control (-19.4 +- 8.4 per cent per 100 micro g/m3 increase in CAP concentration relative to pre-filtered air levels) and fish oil groups (-13.7+-5.3 per cent), while the decrease in the olive oil group was not significant (-7.6+-6.8 per cent).
Tissue plasminogen activator, a protein involved in the breakdown of blood clots, increased (11.6+-5 per cent) immediately after CAP exposure in the olive oil group, and this effect persisted up to 20 hours.