Cod liver oil provides omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Kirkman cod liver oils contain natural Vitamins A and D. The oils have been vacuum-dried and deodorized, plus they have gone through a filtration and distillation process to help remove potentially harmful materials. Omega-3 fatty acids are important in normal development, cardiovascular health and in neurological health. Physicians may prescribe a laboratory profile of fatty acids to determine if they are in proper balance. Cod liver oil can become rancid over time from exposure to air and heat by autoxidation. When this occurs, peroxides develop in the oil. Kirkman adds vitamin E to our cod liver oil to stop any potential oxidation process. In addition, a peroxide test is performed on the oil to ensure a value that will assure freshness. The European Pharmacopeia allows up to 10.0 milliequivalents/kilogram (mEq/kg) of peroxides in cod liver oil to be considered fresh and non-rancid. Kirkman's product has a typical peroxide value of only 2.9 mEq/kg.