Daily supplementation with omega-3 fatty acid (fish oil) prevents a potentially-deadly decline in heart rate variability (HRV) associated with exposure to indoor air pollution, researchers from the US and Canada report.
HRV measures the variability in the intervals between heartbeats, with lower variability being associated with higher risks of heart disease and death.
"Imagine," explained Dr Fernando Holguin, "that a normal heart does not always have the same time intervals between beats, but every so often (in cycles) the interval between cardiac beats changes; ie a little shorter, or longer. How frequent these variations occur are a measure of the effect of the nervous regulation of the heart. It is a fine-tuning that we are not aware of. A sick heart losses this fine tuning."
In the elderly, exposure to fine particulate matter, a common air pollutant, has been associated with reductions in HRV. But in their study of 50 relatively healthy elderly nursing home residents, Holguin and colleagues found that a daily two-gram fish oil supplement prevented a decline in HRV.
Supplementation with soy "control" oil, on the other hand, did not offer significant protection against the harmful effects of indoor air pollution on HRV.
Holguin, from the Centers for Disease Control and Prevention, and colleagues report their finding in the American Journal of Respiratory and Critical Care Medicine.
"A lower HRV may increase the risk of a susceptible person to have a serious cardiac arrhythmia," Holguin told Reuters Health. "In the future, when we identify who is most susceptible to the effects of particulate matter, we could recommend supplementation with omega-3 fatty acids to reduce their cardiovascular risk," he added.