Prevalence of mild hyperhomocysteinemia in vegetarians and vegans is a consequence of vitamin B12 deficiency. Clinical study of homocysteine reduction by vitamin B12 consisted of subjective healthy adults on alternative nutrition (n=9) with vitamin B12 deficiency and with mild hyperhomocysteinemia. Vitamin B12 treatment was implemented by 5 intramuscular cyanocobalamin injections of a total content of 2200 µg during two weeks. Homocysteine level was significantly reduced (from 22 µmol/l to 11.7 µmol/l; individual reduction 29–55 %). Vitamin B12 concentration in blood was significantly increased (from 152 pmol/l to 277 pmol/l; individual%of increase 63–150). The results show a high effect of vitamin B12 treatment in homocysteine value reduction of subjects on alternative nutrition.

        Key words: hyperhomocysteinemia – vegetarians – vegans – vitamin B12