Relative Rates of Depletion of α-Tocopherol and Linoleic Acid After Feeding Polyunsaturated Fats

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Abstract
Rats prefed diets high in polyunsaturated fat (PUFA) and either high in α-tocopherol (safflower oil) or moderately low in α-tocopherol (corn oil) for 109 days were simultaneously depleted of both linoleate and α-tocopherol by substituting a diet containing beef fat. After the rats were on beef fat diet for only seventy-five days, the arachidonate concentration in the hepatic lipids increased to a level which was comparable to that in tocopherol deficiency. From previous experiments, the appearance of such a sign of deficiency in animals fed tocopherol-deficient beef fat diets from the time of weaning would not be expected until after approximately twenty-eight weeks. On the basis of relative rates of depletion of α-tocopherol and linoleate in hepatic and adipose tissue, it is suggested that supplementation with α-tocopherol may be desirable for a period of time after a diet high in polyunsaturated fatty acids is replaced with a diet low in polyunsaturated fatty acids, or if only irregular adherence to the high polyunsaturated fatty acid diet is anticipated or suspected. This recommendation is largely based on the slow net turnover in adipose tissue linoleate.