[Lipids in enteral nutrition: does an optimal ratio between omega-6 and omega-3 exist?]

The ratio between PUFA omega-6 and omega-3 is 3:1 in the unweaned, 5:1 in the young man, 5-10:1 in the adult. The PUFA omega-6 prevail over omega-3 because of elongation and desaturation processes. Linoleic acid is the beginning of the omega-6 series, a-linolenic acid of the omega-3 series. Both acids give rise to PUFA which must be introduced with diet because the human race is not able to synthetize. They represent the 2-6% of total daily caloric intake and correspond about to 10 g every day according to LARN 1986-1987. During some diseases (after surgery, trauma, sepsis, etc.) their need increases until 25-50 g every day, so it is necessary a proper enteral nutrition (EN). For this reason the bromatological composition of diets for EN must respect the physiological ratio between omega-6 and omega-3 PUFA. The composition of 37 diets for EN was examined and it was found that 7 (18%) have a proper ratio between the two series of PUFA. Twenty-three (62%) do not signal any ratio, two have 6:1, two 4.5:1, in three the ratio is in favour of omega-3. Then the concentration of linoleic and alfa-linolenic acid was examined and it was found that 24 (64%) diets signal the concentration of linoleic acid, 10 (27%) of both acids, two have no data about and only one diet reports the concentration of alfa-linolenic acid. A more exact formulation of PUFA into the composition of EN diets is suggested because PUFA are now recognized to play an important role in the fields of inflammation and immunity.