Levels of conjugated dienes of fatty acids (first peroxidation product) in relation to their substrates and promotors (triacylglycerols, homocysteine, iron) as well as to their inhibitors (essential antioxidative vitamins) were assessed in a vegetarian group (n=24) and compared with subjects on a mixed diet (traditional nutrition, n=24). Positive significant linear correlation between conjugated dienes and triacylglycerols, homocysteine, iron as well as inverse relationship between conjugated dienes and vitamin E, vitamin C, beta-carotene were observed in pooled groups. Lipid peroxidation risk in vegetarians seems to be caused predominantly by hyperhomocysteinemia, whereas in a mixed diet group this was due to a higher supply of substrates or risk iron values. The incidence of only 8 % of risk conjugated diene values in vegetarians in contrast to 42 % in the group with traditional diet indicates that vegetarians have a better antioxidative status as a consequence of regular consumption of protective food.