Effects of Non-essential Fatty Acids on Essential Fatty Acid Deficiency

Abstract

The effects of the methyl esters of fatty acids of chain length C₄ through C₁₈, including oleic, elaidic, and linoleic, on essential fatty acid deficiency were studied in feeding tests with rats. Using depressed growth response as a criterion, all of the fatty acid esters except oleate and linoleate accentuated essential fatty acid deficiency, with the esters of fatty acids C₄ through C₁₀ and elaidate exhibiting a much greater effect than the longer-chain fatty acid esters. The highest mortality was observed in females fed caproate, caprylate and laurate and in males fed caprylate, laurate and stearate. When reproductive performance is judged, methyl esters of myristate, palmitate, stearate, oleate and linoleate improved the reproductive performance of female rats fed the fat-free diets and, therefore, partially alleviated the essential fatty acid deficiency. Where cholesterol levels are used as criteria, supplementation with laurate and oleate resulted in an increase in the accumulation of hepatic cholesterol esters over that obtained when an unsupplemented fat-free diet was fed, indicating that laurate and oleate accentuate essential fatty acid deficiency in this respect. It is concluded that several metabolic pathways and physiological responses affected by essential fatty acid deficiency can be influenced by the concomitant presence of non-essential fatty acids. It is further concluded that evaluation of essential fatty acids status should involve more than one measurement.