The composition of plant proteins differs from that of animal proteins. Plant proteins have a greatly reduced content of the essential amino acids methionine and lysine, and some non-essential amino acids are present in larger amounts. The authors assessed from food frequency questionnaires the amino acid status A finding of hypocarnitinaemia was recorded in 33% vegans vs. 3% omnivores and glutathione values below the limit were recorded in 30%persons on an alternative diet as compared with 5% on a traditional diet.The arginine and glycine intake of vegans was significantly increased and the serine and alanine intake is insignifi- cantly higher. Arginine and pyruvate precursors have a protective effect. They reduce the risk of cardiovascular diseases and cancer by stimulating glucagon secretion. The discrepancy of a vegan diet is the risk of inadequate methionine intake and lower levels of its metabolites and its benefit is a higher intake of non-essential amino acids. of adults on an alternative diet (vegans, n=33) as compared with a traditional diet (omnivores, n=37).To facilitate comparison, persons with equal percentage intake of the recommended protein allowance were investigated - plant protein only in vegans, and a ratio of 1:1 of plant and animal proteins in omnivores. The intake of all essential amino acids is significantly lower in vegans. The value of methionine + cystine 1.21 g is 67% of the lower borderline of the interval of optimal reguirement vs. 110% in omnivores (1.98 g).The lysine and tryptophan intake is within the interval of optimal reguirement, the other essential amino acids are slightly higher. In omnivores the intake of all essential amino acids is 1.1-1.9 times higher than the upper limit of optimal reguirement. The authors recorded hypoproteinaemia in 18% vegans vs. 0% in omnivores. The biosynthesis of carnitine and glutathione where methionine acts as substrate is also adversely influenced.

        Key words: vegans - omnivores - plant proteins- methionine - arginine - carnitine - glutathione