Abstract
The importance of dietary polyunsaturated fatty acids for our health and our economy is immense. The present paper is a quick guide to this topic, which is highly complex and full of conflicts. One aspect is highlighted, namely the relationship between these substances and our mental health. Relevant chemical and physical properties of polyunsaturated fatty acids are briefly presented. The questions of needs and supplies are discussed. The effects of these fatty acids on the human body, in particular the brain, are described. How do they influence mental health? The most recent meta-analyses and systematic reviews have been used as sources, and outstanding references have been selected. We want to convey updated knowledge, based on good science, for better decision making in preventive and therapeutic health care, as well as in agriculture, fishery and food industries.