A study, led by Fernando Holguin, Emory University School of Medicine, Atlanta, found that taking daily supplements of fish or soy oil may improve cardiac function and protect against heart attacks in the short-term.
The findings contradict the current belief in the medical community that increasing the intake of omega-3 fatty acids produces only long-term cardiac benefits.
In fact, this study showed improvements in heart function in as little as two weeks.
Researchers examinated the heart rate variability ( HRV ) changes in a cohort of elderly subjects randomized to receive either a daily high dose of marine-derived omega-3 fatty acids ( fish oil ) or a lower daily dose of a plant-derived omega-3 fatty acid ( alpha-linolenic acid ) in soy oil.
A total of 58 elderly nursing home residents were subsequently followed up every other day for a period of 6 months.
The omega-3 fatty acids improve heart function by providing greater variability between beats, therefore reducing the risk of arrhythmia and/or sudden death.
Heart rate variability is measured by high-frequency ( HF ) and low-frequency ( LF ) domain components and standard deviation of normal RR intervals ( SDNN ).
Those who received fish oil experienced a significant increase in total HF and LF domain components and SDNN.
Patients who received soy oil experienced a marginally significant increase in HF and LF domain components and a significant increase in SDNN.
A reduced HRV predicts mortality and arrhythmic complications in patients who have had a heart attack, as well as those who are considered healthy.
According to authors, taking a daily supplement of fish or soy oil may help reduce the risk of suffering an adverse cardiovascular event, such as arrhythmia or sudden death, specially in persons with known cardiovascular disease or at increased risk for it, such as those with lipid disorders, advanced age, hypertension, a history of smoking, and family history of heart disease.
Researchers also discovered that while patients in both groups experienced a significant increase in HRV, those who took the fish oil supplements achieved a greater increase in a shorter time period.
Patients who received fish oil experienced increased HRV within the first 2.7 weeks, whereas it took 8.1 weeks for a significant increase in HRV to be seen in the group taking soy oil.
None of the study participants experienced significant negative side effects, but 41% of participants in the fish oil group reported belching, compared to 16% in the soy oil group.
Source: Chest, 2005