EPA and DHA fatty acid make up two of the most important acids required by the body. Both acids are part of Omega-3 fatty acids. Most people do not get adequate Omega-3 in their daily diet. Studies show that intake of EPA and DHA fatty acids can benefit health conditions like heart disease, high cholesterol levels, depression levels and rheumatoid arthritis, among several others. Although both these fatty acids work together to benefit the body, there are some basic differences between the two.

This Omega-3 fatty acid is better known as Eicosapentaenoic acid. In the chemical structure, it is a carboxylic acid that has five cis double bonds and a 20-carbon chain. EPA fatty acids can be gained by consuming oily fish or fish oil from salmon, mackerel, cod liver, sardine, herring and menhaden.

Studies of EPA on the body have shown significant changes in various medical conditions. Most of these conditions are related to lower inflammation. EPA fatty acid has beneficial potential, especially in schizophrenia. Numerous studies show a great reduction in symptom scales that are used to measure severity of schizophrenic symptoms. Research also suggests that EPA can improve patients' response to chemotherapy. This is possible by adjusting the production of eicosanoid in the body. EPA can also reduce the probability of developing particular kinds of cancer, which includes multiple myeloma. Recent studies have shown that it can reduce depression and suicidal behavior.

Like EPA, the chemical structure of this fatty acid is also a carboxylic acid. However, it has six cis double bonds and a 22-carbon chain. A large amount of DHA can be found in fish oil. This fatty acid can also be commercially manufactured from microalgae. DHA is the most plentiful Omega-3 fatty acid that can be found in the retina and brain.

DHA was recently shown to increase the efficacy of chemotherapy in prostate cancer cells. A chemoprotective effect was also found in a mouse model due to intake of DHA fatty acids. DHA can also found in human breast milk. Concentrations of DHA here can range from 0.07% to more than 1.0%. The level of DHA in human breast milk tends to be high if the mother has a high fish diet. DHA recently achieved attention as an important supplement for pregnant women, as it helps to improve visual and attention acuity. DHA fatty acid is also known to reduce levels of blood triglycerides. This can reduce the risk of heart disease.