Fats, also called fatty acids, are one of three essential macronutrients required daily to support a variety of processes in the body. There are several types of fatty acids, such as essential fatty acids which cannot be made in the body at the quantities needed for healthy function; instead, they must be obtained by the diet to meet the body’s needs. Essential fatty acids can be further divided into categories based on their chemical structure. Omega-3 and omega-6 fatty acids are two types of essential fatty acids that have distinct biochemical differences and exert opposing effects in the body.  Omega-3 fatty acids support healthy inflammation, while omega-6 fatty acids contribute to a pro-inflammatory environment. Health Benefits of DHA Docosahexaenoic acid, or DHA, is a type of omega-3 fatty acid. It can be found in fish, shellfish, fish oils, and can be synthesized from other omega-3 fatty acids found in certain nuts, including walnuts. DHA is an important component of cell structure, affects cellular signaling, and is involved in neurotransmitter action.1 Other health benefits of DHA include supporting cardiovascular health, enhancing cognitive function, promoting healthy inflammation, decreasing triglyceride levels, and supporting healthy blood pressure levels.2 Brain health DHA is required for proper fetal brain development, with rapid accumulation during the last trimester of pregnancy and the first two years after birth; DHA continues to accumulate through adolescence but at a slower rate.3,4 DHA in breastmilk supports brain development in infants, and supplementation with DHA during pregnancy and lactation has been related to visual and mental development and improved cognitive abilities.3,5  As children grow up, DHA remains important for brain function. It is found at high levels in parts of the brain that are responsible for planning, problem-solving, and focused attention.6 Because the brain is constantly being remodeled as old cells die and new cells are generated, it requires a constant supply of DHA and other essential nutrients for healthy brain maintenance.3 Healthy DHA consumption throughout life may also help lower the risk of developing Alzheimer’s’ disease as an important part of neurons in the brain and due to its anti-inflammatory effects, however more research is needed.7 Because most Americans do not consume enough DHA, supplementation with DHA and other omega-3 fatty acids is an excellent option for ensuring adequate intake. In order to see significant elevations in blood DHA levels, supplementation for about one to three months is required.8 DHA Deficiency A diet lacking in DHA can cause health problems throughout the lifespan. If pregnant women do not consume enough DHA, it may result in slow or impaired development of language learning skills, affect behavior in children, and influence disease risk later in life.3 There also appears to be a critical window for correcting maternal DHA deficiency.3 For teenagers and adults, DHA deficiency has been related to autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), cognitive issues, memory problems, and depression later in life.3

Overview of Omega-3's Omega-3s play an essential role in the body. They help maintain healthy cholesterol levels, have anti-inflammatory properties, offer antiarrhythmic benefits, and provide cardiovascular support.1 In addition, Omega-3s support healthy hair, skin, and nails, and promote cognitive function. Given these benefits, many individuals choose to supplement with Omega-3s to ensure adequate intake, especially when their diet may be lacking. Omega-3 supplements typically contain long-chain fatty acids, such as EPA and DHA, which are harder to obtain from food sources alone. Delivery forms of Omega-3's Omega-3 supplements can come in two forms: triglycerides (TG) and ethyl esters (EE). Triglycerides deliver fatty acids bound to a glycerol backbone, which is how these fatty acids are found in whole foods like fish.2 In fish, triglycerides contain a variety of fatty acids, including omega-6, omega-9, saturated fats, and others. To concentrate the desired EPA and DHA from fish oil, a process called ethylation is used. During ethylation, EPA and DHA are isolated from the triglyceride. The isolated omega-3s can either be re-esterified back into an omega-3-rich triglyceride or remain as an ethyl ester, where the omega-3s are bound to an ethanol backbone. Absorption of Ethyl Esters vs Triglycerides When examining the options of omega-3 supplements, it can be confusing to know which form is best.  Clinical research has shown both the triglyceride and ethyl ester forms incorporate into the cells, which is the intended purpose of omega-3 supplementation.3  Additional studies comparing the two forms have found long-term use of ethyl esters or triglycerides do not differ significantly in their absorption.4 Triglyceride forms tend to be absorbed more rapidly, whereas ethyl esters have around a 24-hour sustained absorption rate, providing longer availability of EPA and DHA.5  Interestingly, triglyceride and ethyl ester forms are both best absorbed when taken with a fatty meal or dietary fat.  This has been shown to enhance the bioavailability of both forms.6,7 Conclusion In summary, naturally occurring fish oil contains multiple types of fatty acids.  Concentrating the beneficial EPA and DHA into re-esterified triglycerides or ethyl esters can provide therapeutic levels of these omega-3s.  Clinical studies do not show a significant difference in their ability to replete or maintain EPA and DHA levels within the body, and either form can be utilized to support bodily systems.

Fat, along with carbohydrate and protein, constitutes a basic macronutrient component of food. However, not all fats are created equal. Understanding the differences between the various types of fat is key. There are different types of fat that have various health benefits associated with them.

EPA is an omega-3 polyunsaturated fat found in cold water fish and some edible algae. It is known for its role in cardiovascular health, but its effect on mood disorders is equally impressive.

Specialized pro-resolving mediators are derived from omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic (DHA), and are vital for resolving inflammation.

BrainSpan Founder and CEO Dan Johnston, MD, MPH, discusses the history of human civilization in the context of human health and diet. Specific topics include brain health, the omega-3 index, and clinical application.