The omega-3 fatty acids DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) found in cod liver oil may support heart health, as well as immune and cognitive function. Because cod is a deep, coldwater fish, the fish oil extracted from its liver may contain higher levels of omega-3 essential fatty acids and fewer contaminants than farm raised tuna, salmon, mackerel or herring.
Despite cod liver oil's health benefits, it's advisable to exercise caution when using cod liver oil regularly, as it contains high levels of vitamin A and D, which are toxic in excess. If you're taking a multivitamin and / or vitamin A and / or D supplements concurrent with a cod liver oil regimen, you may want to ensure that you're not getting too much of either, as diminished health may result. The National Institutes of Health and The Office of Dietary Supplements websites contain invaluable information about the recommended daily value of nutrients, deficiencies, toxicity and more.