Linoleic acid, or omega-6 fatty acid, and linolenic acid, or omega-3 fatty acid, are the two essential fatty acids. They are termed as essential because the body cannot synthesize them and needs to obtain them from the diet. A lack of either of the two leads to ill health and causes deficiency symptoms to develop.
Functions of Linolenic Acid
As reported in the “Manual of Dietetic Practice,” linolenic acid is essential for normal growth and development. In the body, linolenic acid is used to make substances called eicosanoids, which regulate inflammation. Linolenic acid is also a component of cell membranes and is converted to the longer chain omega-3 fatty acids eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA. The omega-3 fatty acids deliver numerous health benefits, according to the National Institutes of Health Office of Dietary Supplements.
Special Roles of EPA and DHA
EPA and DHA, the long chain derivatives of linolenic acid, have been associated with a number of health benefits. For example, in regard to cardiac health, these omega-3 fatty acids have been shown to protect against coronary heart disease, sudden cardiac death and heart failure, possibly through anti-arrhythmic, anti-thrombotic, anti-atherosclerotic and anti-inflammatory mechanisms, as reported in the 2009 issue of “Current Pharmaceutical Design.” Other benefits that the “Oxford Handbook of Clinical Medicine” attributes to these omega-3 fatty acids include control of inflammation in arthritic conditions and protection against neurodegenerative diseases.
Functions of Linoleic Acid
Linoleic acid is part of cell components, and is used to manufacture signaling molecules in the body. However, it now appears Western diets contain too much linoleic acid relative to linolenic acid. The March-April 2011 issue of “Nutricion Hospitalaria” reported that current diets have an omega-6:omega-3 ratio of about 20:1, while optimal ratios should probably be closer to 1.5:1. It is recommended that you focus more on increasing your omega-3 fat intake than your omega-6 intake.
Omega-6 fatty acids are found in many plant oils, including palm oil, sunflower oil, flaxseed oil, corn oil and evening primrose oil. Other good sources include nuts, avocados and pumpkin seeds. On the other hand, the best sources of omega-3 fatty acids are oily fish and seaweed, because these contain omega-3 in the form of EPA and DHA. Sources of the parent linolenic acid include flax, purslane, hemp, nuts and organic eggs. Supplements of both linoleic and linolenic acids are readily available. Check with your doctor, however, before adding supplements to your diet, especially if you have health problems or take other medicines.
- Manual of Dietetic Practice, 4th Edition; T. Briony and J. Bishop
- Current Pharmaceutical Design: Polyunsaturated Fatty Acids and Cardiovascular Disease
- Oxford Handbook of Clinical Medicine, 5th Edition; M. Longmore, et al.
- Nutricion Hospitalaria: Importance of a Balanced Omega 6/Omega 3 Ratio for the Maintenance of Health: Nutritional Recommendations
- National Institutes of Health Office of Dietary Supplements: Omega-3 Fatty Acids and Health