While the human body can generate most of the fats it needs, it cannot produce adequate levels of omega-3 fatty acids and must obtain them from dietary sources. Two key omega-3 fatty acids, EPA (eicosatetraenoic acid) and DHA (docosahexaenoic acid), can be derived only from certain sources, such as fish, seafood, enriched foods, and supplements.
In addition to increasing the risk of cardiovascular events, low levels of omega-3 fatty acids in the body have also been associated with inflammation and other adverse health conditions, including cognitive impairment, depression, fetal neurodevelopment, and premature birth. Unfortunately, measuring how much EPA or DHA from food and supplements gets into the bloodstream has been both difficult and invasive. Until now.
Previous tests to measure omega-3 levels required drawing large volumes of blood and performing complicated laboratory work to analyze their omega-3 fatty acid content. As a result, most clinicians haven’t routinely monitored the omega-3 levels of their patients.
To tackle this problem, researchers from McMaster University and the University of Guelph, both located in Ontario, Canada, analyzed fasting blood samples taken from participants in two different cohorts studying omega-3 supplementation. Subjects had received between 3 and 5 grams of fish oil, EPA, or DHA supplements per day. The researchers performed lipid profiling on the samples to isolate specific omega-3 biomarkers from among hundreds of detectable circulating lipids. The results provided a simple way to measure omega-3 levels that can easily be made part of a routine blood panel.
“Our test can be part of a routine blood test without any special requirements,” says Philip Britz-McKibbin, PhD, lead author of the study and a professor of chemistry and chemical biology at McMaster University. “By directly measuring only two specific biomarkers in a blood sample, we can rapidly assess the [omega-3 levels] without time-consuming and costly sample workup protocols prior to analysis.”
“The body’s response to omega-3 supplementation can vary significantly between individuals, with distinct health benefits reported for patients who consumed only EPA, only DHA, or a mixture,” says Britz-McKibbin. “In general, if you have an [omega-3 index, or O3I] below 4 percent, you may have a higher risk for a cardiovascular-related event. Conversely, individuals with an O3I above 8 percent have a lower risk. But since O3I is a modifiable risk factor, you can change it through diet.”
The new method, says Britz-McKibbin, opens the door to regular screening, which should be able to help clinicians understand when fish oil supplementation or dietary changes are necessary based on a patient’s routine labwork. The researchers now plan to identify a surrogate biomarker of omega-3 levels with a urine-based test, which would eliminate the need to draw blood entirely.