Fish oil could play a role in blunting the effects of mental stress, a small study suggests.
Researchers from Michigan Technological University, New York Medical College and the Mayo Clinic found that taking fish oil pills seemed to be protective against the effects of mental stress on the heart, particularly heart rate and muscle sympathetic nerve activity (key in the fight-or-flight response). Fish oil contains omega-3 fatty acids, which have been shown in research to hold numerous health benefits.
"In today's fast-paced society, stress is as certain as death and taxes," study researcher Jason Carter, a researcher at the university, said in a statement. "Moreover, our eating habits have deteriorated. This study reinforces that fish oils may be beneficial for cardiovascular health, particularly when we are exposed to stressful conditions."
The study, published in the American Journal of Physiology: Regulatory, Integrative, and Comparative Physiology, included 67 people without hypertension who were assigned to take either 9 grams of a fish oil supplement for eight weeks, or a placebo of olive oil for eight weeks. Before starting the supplements and at the end of the study period, all the participants underwent blood pressure, heart rate and other testing.
At the end of the study, researchers had the study participants do an arithmetic test, during which their stress responses were measured. They found that the participants who took the fish oil supplements had blunted the reactivity of the muscle sympathetic nerve activity, as well as the effects of mental stress on heart rate. However, fish oil did not seem to have an impact on the reactivity of blood pressure to mental stress.
"These findings support and extend the growing evidence that fish oil may have positive health benefits regarding neural cardiovascular control in humans," the researchers wrote in the study.
While research shows that omega-3 fatty acids may hold health benefits in the form of lowering blood pressure, decreasing atherosclerotic plaque buildup and lowering stroke risk among high-risk people, other research paints a more mixed picture for fish oil supplements in particular. A large review published last year in the Journal of the American Medical Association showed that taking fish oil supplements don't seem to lower risks of heart attack and stroke, nor premature death, Health.com reported. However, the results of this may be due to inconsistencies among all the studies included in the review (like dosing, length of taking the supplements, etc.). And Health.com also pointed out that sometimes nutrients in supplement form don't have the same effects in the body as when a person eats them as food.
However, a recent study in mice published in the Journal of Leukocyte Biology did show that omega-3 fatty acids could help boost activity of B cells, which is a white blood cell that's an integral part of the body's immune response.