Possible Role Of Structural Lipids In Artificial Nutrition - Comparison Of A Linoleic Acid-Based With An Oleic Acid-Based Enteral Formula In Humans

The aim of the study was to evaluate the effects of a linoleic acid (LA)-based, high LA/ alpha-linolenic acid (ALA) ratio enteral formula with those of an oleic acid (OA)-based, low LA/ALA ratio formula, on plasma and red blood cell membrane (RBC) phospholipid fatty acid patterns, neutrophil superoxide anion generation, and eicosanoid production (prostaglandin E2 and leukotrien B4). Two groups of 7 adult male patients who underwent laryngectomy for malignancy received the formulas (LA-group or OA-group) between the lst and the 13th postoperative (po) days. In comparison with the lst po day, at the 14th po day: the LA-group showed an increase of the LA (p < 0.02) and a decrease of the arachidonic acid (p < 0.02) in plasma and a decrease of OA (p < 0.02) and an increase of LA (p < 0.03) in RBC. The OA-group showed an increase of ALA (p < 0.05) in plasma, a decrease of stearic acid (p < 0.05) and an increase of LA (p < 0.05) in RBC. The amount of stearic acid and OA in RBC significantly decreased in the LA-group (p < 0.04) but not in the OA-group. At the 14th po day the LA-group had lower plasma levels of OA (p < 0.01) and ALA (p < 0.05), and higher levels of LA (p < 0.05). The neutrophil eicosanoid production was similar between the two groups, whereas at the 14th po day the superoxide anion generation was greater in the LA-group (p < 0.05). The results indicate that: the LA-formula can impair the conversion of LA to its elongated derivates, increase the RBC membrane content of LA while reducing the amount of saturated-monounsaturated fatty acids. The OA-based formula maintains a better ALA nutritional status and membrane fatty acid pattern. The LA-formula may cause an enhanced inflammatory response.