There is a lot of talk about Omega-3 fatty acids these days, but is their importance to human health a fact or fad? Well, not only is their importance a fact, they are essential! There is growing evidence to support the role these nutrients play in cardiovascular health, inflammation, neurological development and cancer prevention; therefore, understanding the basics of Omega-3 fatty acids could make all the difference in improving and maintaining a healthy lifestyle.
What are Omega-3s?
Omega-3s are a Poly Unsaturated Fatty Acid (PUFA). The American Heart Association states “Polyunsaturated fats are fat molecules that have more than one unsaturated carbon bond in the molecule”.
Poly Unsaturated Fatty Acids are important structural components of cell membranes. Increasing omega-3 fatty acid intake increases the omega-3 content of red blood cells, immune cells (16), atherosclerotic plaques (17), cardiac tissue (18), and other cell types throughout the body.
Omega-3 fatty acids are a specific group of polyunsaturated fats that include any fatty acid with the first double bond located on the third carbon of the fatty acid chain from the methyl end. There are a wide range of these fatty acids; however, the main Omega-3s that are of particular interest to human health include:
- a-linolenic acid (ALA;C18:3 n-3)
- eicosapentaenoic acid (EPA; C20:5 n-3)
- docasahexaenoic acid ( DHA; C22:6 n-3)
Of these Omega-3 fatty acids, only ALA is classified as an “essential” nutrient (1). In other words, ALA is necessary for proper physiological and metabolic activities; however, unlike EPA and DHA, the body cannot produce it from existing precursors so it must come from the diet itself. The biological roles of ALA have particular importance in mediating inflammatory responses and has been suggested to partially protect against rheumatoid arthritis, Crohn’s disease, irritable bowel syndrome and heart heat disease (2). Additional research has suggested that ALA may help in the prevention of neurological conditions such as attention deficit hyperactivity disorder (3). Additionally, the Omega-3 fatty acid ALA also acts as the major precursor for the synthesis of EPA and DHA in the human body. These fatty acids are most commonly associated with brain and vision health while also demonstrating anti-inflammatory properties (4).
- Burr, G.O., and M.M. Burr. 1930. On the nature and role of the fatty acids essential in nutrition. J. Biol. Chem. 86:587 – 621.
- Stark, A.H., M. Crawford, and R. Reifen. 2008. Update on alpha-linolenic acid. Nutri. Rev. 66: 326-332.
- Joshi, K. S. Lad, M. Kale, B. Patwardhan, S. P. Mahadik, B. Patni, A. Chaudhary, S. Bhave, and A. Pandit. 2006. Supplementation with flax oil and vitamin C improves the outcome of Attention Deficit Hyperactivity Disorder (ADHD). Prostaglandins Leukot. Essent. Fatty Acids. 74:17–21.
- Calder, P.C. 2015. Marine omega-3 fatty acids and inflammatory processes: effects, mechanisms and clinical relevance. Biochim. Biophys. Acta.1851:469-484.
What’s the difference between ALA, EPA and DHA?
Of all the omega-3 fatty acids, ALA is the only one that is classified as “essential”. This means it is required for the body to function properly, but it cannot be produced within the body so it must come from the diet (1).
Other omega-3 fatty acids like EPA and DHA can be produced by the body when ALA is present; therefore, these omega-3s are not classified as “essential” nutrients and are not required as part of a healthy diet.
Although EPA and DHA have received much of the spotlight related to their role in human health, ALA also plays a critical role!
Increased consumption of ALA has the potential to protect against inflammatory diseases such as rheumatoid arthritis, Crohn’s disease, irritable bowel syndrome and heart disease. Several studies have also demonstrated comparable health benefits to DHA as it relates to cardiovascular disease prevention.
The three main traits of ALA in the body are:
- It is converted to longer-chained omega-3s like EPA and DHA within the body at different rates, depending on physiological needs
- It represents a key source of healthy dietary energy
- It can be stored in tissues and mobilized for energy or for EPA and DHA production as needed