Millions of people take fish oil supplements to promote heart and vascular health. But a new analysis suggests that some consumers may not always get what they are paying for.
The new research, carried out by a testing company called LabDoor, analysed 30 top-selling fish oil supplements for levels of omega-3 fatty acids, a group of compounds with anti-inflammatory effects. It found that six of those products contained levels of omega-3s that were, on average, 30 per cent less than stated on their labels.
The research found more problems when it looked specifically at levels of two particular omega-3s that are promoted for brain and heart health: docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Tests showed that at least 12 products contained DHA levels that were, 14 per cent less than listed on packaging.
According to the Nutrition Business Journal, like most supplements, fish oil supplements are largely unregulated. Companies do not have to register their products with the Food and Drug Administration or provide proof that the capsules and liquids they sell contain the ingredients on their labels and the doses advertised.
A number of studies suggest that regular fish consumption is protective against heart disease, and some research suggests it may lower the risk of Alzheimer’s disease and other chronic conditions. The American Heart Association recommends two servings a week of fatty fish rich in omega-3 fatty acids, and it points to studies showing that fish oil supplements help reduce the rate of cardiac events in people with cardiovascular disease.
Omega-3s are also essential for brain and nervous system health, said Dr Joseph C Maroon, a neurosurgeon at the University of Pittsburgh Medical Center and the author of “Fish Oil: The Natural Anti-Inflammatory”.
But research on fish oil has not been conclusive. A large meta-analysis of high quality clinical trials published in 2012 found that purified fish oil supplements did not appear to help people with a history of heart disease, though some experts questioned whether the patients studied had been taking the pills long enough to see an effect. Other research has raised questions about whether high levels of omega-3s may raise the risk of prostate cancer.
The company found that several of the products it tested compared favourably to Lovaza, the prescription fish oil marketed by GlaxoSmithKline that can cost hundreds of dollars for a one-month supply. Some of the products analysed contained similar or greater levels of omega-3s at a fraction of the cost.
The analysis showed that mislabeling was not uncommon, affecting at least a third of the supplements tested. The study found that all of the products tested contained only very low levels of mercury, ranging from one to six parts per billion per serving. That is far below the upper safety limit of 100 parts per billion set by the Global Organization for EPA and DHA Omega-3s, or GOED, an industry trade group.