Background. In comparison to food habits of non-vegetarians alternative nutrition bears several risks, but it also has beneficial effects. Considering risks represent a significant age aspect. Nutritional risk and protective factors were evaluated in a adolescent group. Methods and Results. Food habits of 53 lactoovovegetarians (mean duration of vegetarianism 3.2 y) assessed by analysis of dietary questionnaires were compared to those of 55 nonvegetarians and evaluated with respect to basic biochemical indicators (iron, hemoglobin, calcium, total protein, cholesterol, fatty acids, vitamin A, b-carotene, vitamin C, vitamin 3). Vegetarians consume less fat, and they have higher intake of plant fat, which is reflected din more favourable lipid levels, i.e. lower risk parameters of atherosclerosis (cholesterol, LDL-cholesterol, atherogenic index, saturated fatty acids) and higher values of factors with antisclerotic effect (32.9% ratio of HDL-cholesterol vs. 30.6 % in non-vegetarians, polyunsaturated fatty acids, vitamin E/cholesterol ratio, vitamin C). Total plasma protein levels are balanced in both groups (intake of full value mixture of amino acids from grains, legumes (soya), and mild in vegetarians, similar intake of total proteins with a small difference in plant protein consumption). Iron and calcium absorption is inhibited in vegetarians as a consequence of presence of plant food - physic acid, oxaloacetic acid (20.7% hyposiderinemia vs. 0 % in non-vegetarians, high iron intake in both groups, iron from plant sources represented 82 % in vegetarian boys and 95 % in vegetarian girls, hypocalcemia in 28% of vegetarians vs. 7.3 % of non-vegetarians). Vegetarians have significantly higher levels of all antioxidant vitamins. This is result of higher consumption of vegetables, fruit, plant fat and sprouts. Higher intake and higher levels of antioxidants are reflected in significantly lower lipoperoxidation values. Conclusions. Lactoovovegetarian nutrition represents risk for adolescents if the values of iron and calcium are considered, however it has positive aspects on lipid parameters, protein values, and antioxidant parameters.

        Key words: adolescents, lactoovovegetarians, non-vegetarians, lipids, iron, calcium, antioxidative vitamins.