Reduction of essential fatty acid deficiency in rat fed a low iron fat free diet.

Young male rats were fed ad libitum for 8 weeks a low iron fat-free (FF-Fe) diet or a fat-free diet supplemented with iron (FF+Fe). The relative levels of 16:1 and 18:1 to 18:0 in the total fatty acids of liver and other tissues (plasma, erythrocytes and intestinal mucosa) were considerably decreased because of a lack of dietary iron. In rats fed the FF-Fe diet, the levels of essential fatty acids (18:2 omega 6 + 20:4 omega 6) in tissues were 2- to 3-fold greater than in the corresponding tissues of rats fed the FF+Fe diet. Eicosatrienoic acid (20:3 omega 9) levels in tissue lipids from rats fed the FF+Fe diet were high (8-16%), whereas they were low (2-5%) in the case of animals fed the FF-Fe diet. The proportion of 20:4 in total fatty acids of tissues was 2- to 3-fold greater in rats fed the FF-Fe diet than when they were fed the FF+Fe diet. Therefore, the relative levels of 20:3 omega 9/20:4 omega 6 varied from 1-2.9 in tissue lipids of rats fed the FF+Fe diet, while it varied only from 0.2-0.3 in animals fed the FF-Fe diet. These results suggest that a lack of dietary iron may reduce the synthesis of 16:1, 18:1, 20:3 and 20:4 and the metabolism of 20:4.