Nonadecanoic Acid is an odd chain fatty acid.

Fatty acids with odd numbers of carbon atoms are produced primarily by initiating the synthetic series with the three carbon compound, propionic acid.

Vitamin B12 is required for the conversion of propionate into succinate for oxidation in the central energy pathways.

Deficiency of vitamin B12 results in accumulation of propionate and subsequent buildup of the odd numbered fatty acids, pentadecanoic, heptadecanoic, nonadecanoic, heneicosanoic, and tricosanoic acids.

The bacteria in the gut of ruminants (grazing animals like cows and sheep) produce large amounts of propionate, which is absorbed and enters the metabolism of the animal. High intake of animal and dairy products favor high levels of these fatty acids.

Alternatively, it is possible that the bacteria in the human gut could produce sufficient amounts of propionate to lead to elevation in the odd-carbon fatty acids. This would only occur under conditions of significant gut dysbiosis.

Carnitine is required for fatty acid oxidation. In carnitine insufficiency, fatty acids are oxidized via an omega oxidation pathway that creates odd chain units. Therefore, odd chain fatty acid accumulation may indicate carnitine deficiency and the need for carnitine supplementation.

The odd numbered fatty acids containing 15, 17, 19, or 21 carbon atoms (heptadecanoic acid, nonadecanoic acid, tricosanoic acid, pentadecanoic acid) accumulate in vitamin B12 deficiency.

References:

– https://www.gdx.net/core/interpretive-guides/Fatty-Acids-IG.pdf