The Federal Research Center of Vegetable Growing has developed the cultivars Valentina (Amaranthus tricolor L.) and Krepysh (Amaranthus cruentus L.), which are successfully grown in several regions of Russia. The dry periods observed in recent years have a negative impact on the development of plants. The red-colored vegetable cultivar demonstrated a higher level of adaptability to drought than the green-colored grain cultivar. It was found that only in the leaves of cv. Valentina multiple spiked crystals consisting of four elements were formed, the predominant proportion belonged to Ca (38.59), then P (0.48), Mg (0.25), and K (0.16) followed, weight%, respectively. Under the conditions of moisture deficiency, the antioxidant activity of water and ethanol extracts in the leaves of both types of amaranth increased from 1.5 to 2.5 times. It was established that under drought conditions, the carbohydrate metabolism and the synthesis of secondary metabolites change. The leaves of the new cultivar of amaranth Valentina are a promising and reproducible source of antioxidants and can be used to create phytobiological preparations. The increased level of the main macro- and microelements—Ca, K, P, Mg, Mo, S and Cl in the seeds of cv. Valentina and Krepysh makes these cultivars promising for use in the food industry.