If you want to get the most out of your omega-3 supplement, here’s a trick that may help: Make sure to eat some dark green vegetables every day. That’s the surprising finding of a study conducted by researchers from the University of California, Davis and the USDA’s Agricultural Research Service.
The scientists didn’t set out to test the idea that green veggies could boost omega-3 bioavailability; they were investigating what effect omega-3s have on cardiovascular health. But in a secondary analysis of their data, they were surprised to find a link between consumption of dark green veggies and red blood cell (RBC) omega-3 levels.
During the study, 83 healthy people were randomly divided into two groups. One group received omega-3 supplements (providing 2 grams of EPA and 1 gram of DHA) and the other received placebo pills (made of corn/soybean oil) for six weeks.
Even though all of the folks in the supplemented group were taking the same amount of omega-3 daily, some of them were “high responders,” meaning their levels of RBC omega-3 shot up dramatically, while others were “low responders,” meaning their levels rose much more modestly. In fact, the DHA levels of the high responders increased three times as much as that of the low responders, while their EPA levels increased tenfold!
Individual variation in people’s ability to absorb and utilize omega-3s is normal. But there was one key difference between the high and low responders in this study: how many dark green vegetables — such as leafy greens, broccoli, salad, and spinach — they ate. People who regularly consumed more green veggies absorbed more omega-3. The researchers hypothesized that omega-3 bioavailability may decline in the presence of oxidative stress caused by free radicals, and that since dark green vegetables fight free radicals, they may increase omega-3 absorption.
The good news is that you don’t need to have broccoli coming out of your ears to reap an absorption benefit. In the study, eating just 0.3 cups per day of dark green vegetables, in combination with taking the omega-3 supplement, was enough to raise the participants’ omega-3 index to 8%, considered to be the target for optimal health.
 O’Sullivan A, et al. J Nutr. 2014 Feb;144(2):123-31.