| Abstrakt: |
The author has shown1, 2that the methyl esters of linoleic and linolenic acids interfere with the utilization of carotene and vitamin A by vitamin-A deficient rats. It was found that this antagonism can be counteracted by the addition of soybean oil and is not apparent if sufficiently large amounts of carotene are fed.Subsequent investigations have revealed that the antagonism between the unsaturated fatty acid esters and carotene can be prevented by the unsaponifiable fraction of soybean oil or by α-tocopherol; but not by choline, ethanolamine, or soybean lecithin or cephalin.The growth obtained with carotene and α-tocopherol was only slightly better than that with carotene alone, but the addition of α-tocopherol to carotene and methyl linolate or linolenate gave a pronounced growth response. The antagonism between methyl linolenate and carotene was more pronounced than that between methyl linolate and carotene. The addition of α-tocopherol gave better growth with methyl linolate than with methyl linolenate.It is improbable that α-tocopherol acts as a simple chemical antioxidant since in vitroexperiments2have shown that the unsaturated fatty acid esters cause no direct destruction of carotene with the method of feeding employed. It appears that in the absence of α-tocopherol there is a physiological antagonism between unsaturated fatty acids and carotene which results in the inefficient utilization of carotene. |
