Nervonic acid

Nervonic acid (24:1, n−9) is a fatty acid. It is a monounsaturated analog of lignoceric acid (24:0). It is also known as selacholeic acid and "cis"-15-tetracosenoic acid.
It exists in nature as an elongation product of oleic acid (18:1 Δ9), its immediate precursor being erucic acid. Nervonic acid is particularly abundant in the white matter of animal brains and in peripheral nervous tissue where nervonyl sphingolipids are enriched in the myelin sheath of nerve fibers.
In the same way, recent studies have concluded that nervonic acid is implicated as an intermediate in the biosynthesis of nerve cell myelin.
This acid is an important member of the group of the cerebrosides, which are fatty acids of the glycosphingolipids group, important components of the muscles and the central nervous system and peripheral. Indeed, it is one of the major fatty acids in brain sphingolipids, normally accounting for approximately 40% of the total fatty acids in sphingolipids.
Structure.
As it is defined as a monounsaturated fatty acid, it has one double bond in the fatty acid chain and all the remaining carbon atoms are single-bonded.
It is classified in the sub-group of very long chain fatty acids (VLCFA), which includes molecules containing more than 20 carbon atoms. It has specifically 24-carbon backbone and the sole C=C double bond originating from the methyl end is in n-9 or omega-9 (ω-9).
Functions.
Nervonic acid is an essential nutrient for the growth and maintenance of the brain.
This acid has been found in breast-milk: it is said it can speed the development in infants. It is the reason why it is recommended to pregnant and nursing women.
This acid is a regulator of the Ca2+ ion channel in the cell membrane of nerve tissues, so nervonic acid plays an important role in the control of the levels of calcium of the cytosol.
Nervonic acid can regulate the function of brain cell membranes and have a neuroprotective effect which is important to high-level training adults or athletes: it is an energy supplement.
Moreover, due to its function as an intermediate in myelin biosynthesis, dietary therapy with nervonic acid-containing fats has been studied: nervonic acid appears to be beneficial for the treatment of genetic disorders of the lipid metabolism, such as Zellweger syndrome or adrenoleukodistrophy. Nervonic acid beta-oxidation takes place in peroxisomes, and this oxidation is impaired in X-ALD patients. Due to different mutations, people having these disorders have ineffective peroxisomes. It causes an important accumulation of very long chain fatty acids, that can be treated with oils enriched with 24:1 (Lorenzo's oil, Lunaria's oil).
It is also used as a biomarker to predict who will suffer some psychoses. For instance, there is evidence of abnormal levels of fatty acids in individuals with schizophrenia. In particular, decreased levels of 24:1 are related with prodromal psychosis symptoms so it can be beneficial in the prevention and treatment of this kind of disorders.
Nervonic acid can be an indicator of future neurodevelopmental disorders in male babies whose mother has preeclampsia. Recent studies show that cord nervonic acid levels were lower in women with preeclampsia delivering male babies as compared to normotensive control group. But this does not happen with girl babies. These results suggest that male babies born to mothers with preeclampsia may be at an increased risk of developing neurodevelopmental disorders as compared to female babies.
This acid is present in the composition of aged eye lens, but it does not appear in normal eye lens. This data shows that we can use the presence of nervonic acid (together with heneicosylic acid and docosahexaenoic acid) as biomarkers of aging lens, which is the most vulnerable stage for cataract development.
Sources.
Nervonic acid occurs in seed oil of plants, where significant amounts are contained. Indeed, more than 10% of the lipids contain nervonic acid, usually in the form of triglycerides. The seed oils of "Lunaria" species ("Lunaria biennis" or "Lunaria annua", for example) are a quite important source of this long chain fatty acid, since they contain over 20% of it in the triglyceride lipid. Nervonic acid is also found in "Cardamine gracea", "Heliophila longifola", and "Malania oleifera". In all these species, 24:1 usually is esterified at the sn-1 and sn-3 positions on the glycerol backbone. Other sources can be the molds "Neocallimastix frontalis", the bacterium "Pseudomonas atlantica", the yeast "Saccharomyces cerevisiae", and the marine diatom "Nitzschia cylindrus".