The necessity of appropriate nutrition with diets containing omega-3 and omega-6 fatty acids for physiologically optimal brain and nervous tissue function has been demonstrated in numerous experiments conducted in very prestigious research laboratories worldwide. Complex mechanisms and dysfunctions in the area of developmental neurobiology and neurology are impossible to understand and describe in detail without the interdisciplinary study of diet and nutrition. Studies of human infants suggest that dietary docosahexaenoic acid plays an important role in cognitive development and, in cases of its deficit, in some neurodevelopmental disorders as well; this possibility has important public health implications. Both omega-3 and omega-6 fatty acids are crucial elements in the structure and function of cellular membranes, determining their proper physiological activity in regards to fluidity, intracellular transport, and protection against intruders such as bacteria and viruses. These acids actively participate in the biosynthesis of such neurotransmitters as dopamine and serotonin, which are required in nerve cells for quick and efficient signal conductance. The proper content of omega-3 fatty acids in diets increases and improves learning ability, problem-solving skills, concentration, memory, and communication between nerve cells. Omega-3 fatty acids also support positive mood and emotional balance, and are beneficial in the treatment of depression and Alzheimer’s disease; they also help maintain good mental skills in aging people. Omega-3 fatty acids are derived from food; they are able to restore the proper flexibility of neuronal membranes, resulting in improved cell communication and physiologically optimal brain function in cases in which this flexibility was previously disordered.