vaccenic

Vaccenic acid is a naturally occurring monounsaturated fatty acid with the chemical name trans-11-octadecenoic acid (18:1 trans-11). It is one of the trans fats found in certain animal fats and dairy products, produced primarily through the biohydrogenation of unsaturated fats by microbial activity in the rumen of ruminant animals.

Natural occurrence and sources include milk fat, cheese, butter, beef, and other ruminant-derived foods. Vaccenic acid is typically present as a minor to moderate component of the total fatty acid profile in these fats, with levels varying by species, diet, and processing. It is one of several trans fats that occur naturally in contrast to industrially produced trans fats.

Metabolism and bioconversion: In humans, vaccenic acid is absorbed from the diet and can be partially converted into conjugated linoleic acid (CLA), specifically the cis-9, trans-11 isomer (rumenic acid), through the action of delta-9 desaturase in body tissues. This potential conversion links vaccenic acid to some of the biological effects studied for CLA, though the extent and significance of the conversion can vary among individuals.

Health and regulation: Health implications of vaccenic acid are less controversial than those of industrial trans fats, as it occurs naturally in foods from ruminant sources. Some studies have explored possible roles in lipid metabolism, immune function, and cancer risk via its relationship to CLA, but evidence for specific health benefits or risks of vaccenic acid alone in humans remains inconclusive. Dietary guidance generally emphasizes moderation of total fat intake and a balanced consumption of dairy and meat from ruminant sources.

See also: Conjugated linoleic acid, trans fatty acids, ruminant fat.