Cunnane S C, Anderson M J
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Canada.
J Lipid Res. 1997 Apr;38(4):805-12.
Essential fatty acid deficiency has been widely studied but the extent to which its effects are attributable specifically to deficiency of linoleate as opposed to deficiency of all unsaturated fatty acids is unknown. Our objective was to evaluate the effect of pure linoleate deficiency on growth as well as changes in the metabolism and oxidation of n-6 polyunsaturates. The diets contained 20 energy % fat blended from 3 energy % pure oleate, 2 energy % linoleate (0.01 energy % in the linoleate-deficient group), 0.3 energy % pure alpha-linolenate, and the balance as palmitate and stearate from fully hydrogenated soybean oil. Thirty-five-day-old rats consumed the two diets for 84 days, after which the linoleate-deficient rats weighed 15% less than the controls (P < 0.05), had mild scaling on the paws, and visible hair loss (in a few rats). Compared with the controls, the ratio of eicosatrienoate to arachidonate after 84 days was elevated in liver (170-fold) and serum (520-fold) phospholipids of the linoleate-deficient group. In total, linoleate-deficient rats consumed 122 mg of linoleate and had a net whole body loss of 479 mg n-6 polyunsaturates compared with an intake of 24,130 mg and a net whole body gain of 7206 mg n-6 polyunsaturates in the control group. Linoleate-deficient rats oxidized 1% of an oral bolus of [1-14C]linoleate over 8 h compared with 34% in the control rats (P < 0.05). We conclude that pure linoleate deficiency has marked effects on accumulation of n-6 polyunsaturates but induces milder gross symptoms, particularly growth retardation, than classical essential fatty acid deficiency. alpha-Linolenate and possibly oleate may have a sparing effect on linoleate oxidation from body stores during linoleate deficiency.
必需脂肪酸缺乏已得到广泛研究，但与所有不饱和脂肪酸缺乏相比，其影响在多大程度上具体归因于亚油酸缺乏尚不清楚。我们的目的是评估纯亚油酸缺乏对生长以及n-6多不饱和脂肪酸代谢和氧化变化的影响。日粮含有20%能量的脂肪，由3%能量的纯油酸、2%能量的亚油酸（亚油酸缺乏组为0.01%能量）、0.3%能量的纯α-亚麻酸以及其余来自完全氢化大豆油的棕榈酸和硬脂酸混合而成。35日龄大鼠食用这两种日粮84天，之后亚油酸缺乏组大鼠体重比对照组轻15%（P<0.05），爪子有轻度脱屑，并有明显脱发（少数大鼠）。与对照组相比，84天后亚油酸缺乏组大鼠肝脏（170倍）和血清（520倍）磷脂中二十碳三烯酸与花生四烯酸的比值升高。总体而言，亚油酸缺乏组大鼠摄入了122mg亚油酸，全身n-6多不饱和脂肪酸净损失479mg，而对照组摄入24130mg，全身n-6多不饱和脂肪酸净增加7206mg。亚油酸缺乏组大鼠在8小时内氧化了口服[1-14C]亚油酸丸剂的1%，而对照组大鼠为34%（P<0.05）。我们得出结论，纯亚油酸缺乏对n-6多不饱和脂肪酸的积累有显著影响，但比经典的必需脂肪酸缺乏引起的总体症状较轻，尤其是生长迟缓。在亚油酸缺乏期间，α-亚麻酸以及可能的油酸可能对机体储存的亚油酸氧化有节约作用。
