Tricosanoic C23:0

Tricosanoic acid is an 23-carbon, odd-chain saturated fat (23:0) synthesized initially from propionic acid and can be derived in the diet from sesame, sunflower, and hempseed oils. It can furthermore be found in milk and dairy products, as well as some wild mushroom species. It can also be endogenously made.

Most research in fatty acid metabolism has focused on even-chain fatty acids since they represent >99% of total human lipid concentration. For years, it had been concluded that odd chain saturated fatty acids (OCSFAs) were of little significance and used only as internal standards in laboratory methodology. However, there is now a realization that they are, in fact, relevant and important physiologically.

OCS-FAs mainly originate from dairy fat since microbiome fermentation in ruminant animals is a primary source of production. The human body can also synthesize them by elongating propionic acid, a short chain fatty acid formed in the microbiome. New research is showing they may also be formed by shortening VLCFAs by removing carbon molecules using α-oxidation. Metabolism of OCS-FAs is a bit different than even-numbered chained fatty acids. Both odd and even chain fatty acids undergo oxidation, though OCS-FAs produce a molecule of propionyl-CoA and a molecule of acetyl-CoA instead of two acetyl-CoAs. Propionyl-CoA requires a vitamin B12-dependent enzyme to be converted into succinyl-CoA and used in the citric acid cycle. It should be noted that the microbiome is not the only source for the OCS-FA precursor propionate. Endogenous propionate can be produced by the degradation of some amino acids, which can then lead to OCS-FA production.

Several epidemiologic studies show a positive association between OCS-FA and reduced risk for inflammation, cardiometabolic disease, multiple sclerosis, and nonalcoholic steatohepatitis. They are also being studied as adjuvant therapies in cancer due to their cell signaling properties which induce targeted apoptosis. Additionally, it has been found that OCS-FAs increase membrane fluidity more than PUFAs, and they are being studied as a form of treatment for Alzheimer’s disease.

References:

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