Effects of dietary methionine and vitamin B<SUB>12</SUB> on the net synthesis of choline in rats

The base moiety of tissue lecithin appears to arise from dietary components other than choline. Although the presence of choline in the diet is essential for maintaining the health of the animals, supplements of choline do not increase the amount of this base found in the bodies of rats paired-fed purified diets. In contrast, dietary supplements of methionine and of vitamin B12 do increase the total choline content of the carcass of rats