In a study with 12 healthy Beagles, researchers investigated how long omega-3 fatty acids from fish oil stay elevated in the blood after stopping fish oil supplements. The dogs were fed either soybean or fish oil diets for 8 weeks. After switching to a normal diet, the levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the blood stayed higher for 3 to 7 weeks even after fish oil was no longer given. This means that feeding dogs fish oil can have lasting effects on their blood fatty acid levels even after they stop eating it.