1. A composition for the prevention or treatment of infirmity in a mammal, containing at least two components selected from the group (i) of a nucleoside analog selected from the group of uridine, deoxyuridine, uridine phosphates (UMP, dUMP, UDP, UTP), uracil and acylated derivatives uridine, (ii) ω-3 polyunsaturated fatty acid selected from the group of DHA, DPA and EPA, (iii) vitamin B selected from the group of vitamin B6, vitamin B12 and vitamin B9, (iv) phospholipid, (v) an antioxidant selected from the group of vitamin C, vitamin E and selenium, and (vi) choline, subject to the presence of Via at least the component (i), wherein the composition is intended for administration to a human suffering from a disorder selected from the group consisting of dementia and Alzheimer's disease while such person has BMI below 26.2. A composition for the prophylaxis or treatment of infirmity in a mammal, comprising at least three components selected from the group (i) of a nucleoside analog selected from the group of uridine, deoxyuridine, uridine phosphates (UMP, dUMP, UDP, UTP), uracil and acylated derivatives of uridine, (ii) ω-3 polyunsaturated fatty acid selected from the group of DHA, DPA and EPA, (iii) vitamin B selected from the group of vitamin B6, vitamin B12 and vitamin B9, (iv) phospholipid, (v) antioxidant, and (vi) choline, subject to the presence of at least component (i), while this comp zitsiya intended for administration to a human suffering from Alzheimer's disease, at the same time a man has a BMI below 26.3. A composition for the prophylaxis or treatment of infirmity in a mammal, comprising at least four components selected from the group (i) of a nucleoside analog selected from the group of uridine, deoxyuridine,1. Композиция для профилактики или лечения немощности у млекопитающего, содержащая по меньшей мере два компонента, выбранных из группы (i) нуклеозидного аналога, выбранного из группы уридина, дезоксиуридина, фосфатов уридина (UMP, dUMP, UDP, UTP
