Origin of circulating TPA at the present time and in the forthcoming period: exclusive contribution of ruminant fats to the intakes and circulating levels of TPA in countries where partially hydrogenated oils are not used anymore. Abbreviations. PHFO, partially hydrogenated fish oil; PHO, partially hydrogenated oil (includes PHFO and PHVO); PHVO, partially hydrogenated vegetable oil; TPA, trans-palmitoleic acid; TVA, trans-vaccenic acid.