The homogeneity of crops used for human nutrition is the reason why diets often do not meet the requirements for a nutritionally balanced food and can cause health problems. Because of that, more studies should be carried out in order to clarify nutritional aspects of underutilized crops or varieties and encourage their consumption. Quinoa (Chenopodium quinoa Willd.), for example, contains several compounds whose functional properties can improve nutritional quality of human diet. Thus, the content of selected compounds - vitamins and antioxidants - was determined in seeds of several quinoa varieties and compared with selected varieties of barley and wheat. Target analytes - vitamin E isomers, vitamin B1 (thiamine), vitamin B2 (riboflavin) and vitamin B6 (pyridoxine) were determined by HPLC with fluorescence detection. The activity of the antioxidant enzyme superoxide dismutase (SOD) was determined using a commercial set based on the inhibition of the reaction of colour complex formation. Grain characteristics were obtained using imaging techniques. The content of target analytes was evaluated in the seeds of six quinoa genotypes grown in two different localities in the Czech Republic (Žabčice and Olomouc). At the same time, the ability of these varieties to adapt for growing conditions was assessed. The quinoa genotypes revealed a wide range of the content of monitored substances, depending on environmental conditions. Small-scale experiments with the "Titicaca" variety carried out in the Czech Republic enabled the specification of several recommendations for quinoa breeding described in this paper. The results unambiguously demonstrated the potential of quinoa use for overall improvement of human diet quality and further confirmed the effect of different genotypes and growth conditions on the content of functional substances in quinoa, as well as the assumptions of adaptation possibilities of some of its varieties to mild climatic conditions.