[1][3][4] Essential fatty acids are needed for various cellular metabolic processes and for the maintenance and function of tissues and organs.
[1][5] These fatty acids also are precursors to vitamins, cofactors, and derivatives, including prostaglandins, leukotrienes, thromboxanes, lipoxins, and others.
Since biological fatty acids can be of diverse lengths, the last position is often labelled as "ω", the last letter in the Greek alphabet.
In the expression ω−x, the minus symbol represents subtraction, indicating how many carbons away from the terminal end (ω) of the chain that the first unsaturated carbon-carbon bond appears.
Both AA and DHA are present in breastmilk and contribute along with the parent fatty acids LA and ALA to meeting the requirements of the newborn infant.
Essential nutrients are defined as those that cannot be synthesized de novo in sufficient quantities for normal physiological function.
They found that patients undergoing intravenous nutrition with glucose became isolated from their fat supplies and rapidly developed biochemical signs of essential fatty acid deficiency (an increase in 20:3n−9/20:4n−6 ratio in plasma) and skin symptoms.
[15] This could be treated by infusing lipids, and later studies showed that topical application of sunflower oil would also resolve the dermal symptoms.
Some plant-based foods contain omega−3 in the form of alpha-linolenic acid (ALA), which appears to have a modest benefit for cardiovascular health.
[23] The human body can (and in case of a purely vegetarian diet often must unless certain algae or supplements derived from them are consumed) convert ALA to EPA and subsequently DHA.
[25] The National Institutes of Health's EFA Education group publishes Essential Fats in Food Oils.
[28][29][30][31] Additionally, essential fatty acids are crucial for the development of several endocannabinoids with a multitude of functions in the body, such as docosahexaenoyl ethanolamide (DHA-EA/synaptamide).
Reference intake values for as published by the Panel on Dietetic Products, Nutrition and Allergies of the European Food Safety Authority (EFSA).
Studies have shown that smaller intakes reverse the symptoms of deficiency, but there is inadequate information to set an Estimated Average Requirement (EAR) for either.