Cigarette smokers – a group at increased risk of heart problems – may benefit from daily omega-3 supplements, suggest data from a gold-standard randomized control trial.
Although the best advice for smokers is to quit smoking, for those who continue with their habit a daily dose of omega-3 fatty acids may improve the function of the cells lining blood vessels (endothelial cells), according to findings published in the journal Heart .
“We have demonstrated that omega-3 fatty acid supplements improve endogenous fibrinolysis [the breakdown of blood clots] and endothelial function in healthy cigarette smokers, a group at high risk of adverse cardiac events,”wrote researchers from the University of Edinburgh (Scotland), Wellington Hospital (New Zealand), and Wythenshawe Hospital (Manchester, UK).
“These distinct but complementary measures of vascular function may represent important mechanisms through which omega-3 fatty acids confer their potential cardiovascular benefits.”
The heart health benefits of fish oil, and the omega-3 fatty acids it contains, are well-documented, being first reported in the early 1970s by Dr Jorn Dyerberg and his co-workers in The Lancet and The American Journal of Clinical Nutrition.
To date, the polyunsaturated fatty acids (PUFAs) have been linked to improvements in blood lipid levels, a reduced tendency of thrombosis, blood pressure and heart rate improvements, and improved vascular function.
Commenting on the study, Harry Rice, PhD, VP of scientific and regulatory affairs for GOED, said: "Abnormal endothelial function is common in individuals with cardiovascular risk factors (e.g. smoking). While this study may have demonstrated improved endothelial function in smokers taking n-3 LCPUFA supplements, it's unlikely to match the endothelial function seen in non-smokers.
"Thus said, n-3 LCPUFAs, from fish and/or supplements are just part of the equation for a healthy lifestyle. If you smoke, quitting is another key factor."
Increased risk for smokers
The risk of heart disease and heart attack is well-known to be significant higher for cigarette smokers. According to the researchers behind the new study, compared to non-smokers, smokers do not produce very much of tissue plasminogen activator (t-PA), which is responsible for the breakdown of clots in blood vessels.
Daily omega-3 doses of two grams per day for six weeks (Omacor capsules, Pronova, Norway) were associated with increase t-PA levels more than double the levels observed in the placebo group, said the researchers (8.8 IU/ml compared with 3.6 IU/ml, respectively).
Results of the randomized, double-blind, placebo-controlled, crossover trial involving 20 male cigarette smokers also indicated that levels of substances known to dilate blood vessels, and thereby improve blood flow, were also higher in the omega-3 group, compared with placebo.
“We have demonstrated for the first time that omega-3 fatty acids augment acute endothelial t-PA release and improve endothelial vasomotor function in cigarette smokers,” wrote the researchers.
“The omega-3 fatty acid supplement used in this study is a highly purified, pharmaceutical grade preparation containing concentrated omega-3 fatty acid ethyl esters,” they added.
“The selected dose was chosen to be similar to that seen to reduce cardiac events in clinical trials, and lower than doses which decrease triglyceride concentrations.
“There are many commercially available omega-3 fatty acid supplements, with wide variability in the content and composition of fatty acids. Therefore, the results of the present study cannot be extrapolated to other omega-3 preparations or doses.”
February 2013, Volume 99, Number 3, Pages 168-174, doi: 10.1136/heartjnl-2012-302924
“Effect of ω-3 fatty acid supplementation on endothelial function, endogenous fibrinolysis and platelet activation in male cigarette smokers”
Authors: Din JN, Archer RM, Harding SA, Sarma J, Lyall K, Flapan AD, Newby DE.