MOLECULE

alpha-Linolenic acid

alpha-Linolenic acid (ALA) is a polyunsaturated fatty acid (PUFA). It is a member of the group of essential fatty acids called omega-3 fatty acids. alpha-Linolenic acid is not synthesized by mammals and therefore is an essential dietary requirement for all mammals. Omega-3 fatty acids get their name based on the location of one of their first double bonds. In all omega-3 fatty acids, the first double bond is located between the third and fourth carbon atom counting from the methyl end of the fatty acid (n-3). Although humans and other mammals can synthesize saturated and some monounsaturated fatty acids from carbon groups in carbohydrates and proteins, they lack the enzymes necessary to insert a cis double bond at the n-6 or the n-3 position of a fatty acid. Certain nuts (English walnuts) and vegetable oils (canola, soybean, flaxseed/linseed, olive) are rich in alpha-linolenic acid. Linolenic acid is a fatty acid found in hemp seed oil of cannabis plants, first reported by Prior et al. in 1968 (PMID: 6991645). Omega-3 fatty acids like alpha-linolenic acid are important structural components of cell membranes. When incorporated into phospholipids, they affect cell membrane properties such as fluidity, flexibility, permeability, and the activity of membrane-bound enzymes. Omega-3 fatty acids can modulate the expression of several genes, including those involved with fatty acid metabolism and inflammation. alpha-Linolenic acid and other omega-3 fatty acids may regulate gene expression by interacting with specific transcription factors, including peroxisome proliferator-activated receptors (PPARs) and liver X receptors (LXRs). alpha-Linolenic acid is found to be associated with isovaleric acidemia, which is an inborn error of metabolism. Patients with isovaleric acidemia have a defect in leucine catabolism resulting from a deficiency in the enzyme isovaleryl-CoA dehydrogenase. These patients do well on a low protein/low leucine diet but a low protein diet can lead to deficiencies in essential fatty acids, such as alpha-linolenic acid ( https://doi.org/10.1038/ejcn.2016.100).