Breastfeeding has a major impact on public health, since human breast milk is the best food for infants up to six months of age. The lipid fraction in human milk is the main source of energy for the infant and supplies essential nutrients such as fat-soluble vitamins and polyunsaturated fatty acids (PUFA). Essential fatty acids (EFA), specifically linoleic acid (LA, 18:2n-6) and alpha-linolenic acid (ALA, 18:3n-3), are precursors of long-chain polyunsaturated fatty acids (LC-PUFA), including docosahexaenoic (DHA) and arachidonic (ARA) acids. Quality of lipids in secreted milk is precisely related to maternal ingestion. LC-PUFAs protect against allergy and infection and are important for visual and cognitive development in infancy. Industrial food processing has introduced the trans fatty acids (TFA) among the nutrients available to the population. TFA can interfere with the metabolism of essential fatty acids by decreasing LC-PUFA synthesis. It is thus important to raise population awareness on the importance of adequate PUFA consumption and reduced TFA intake during prenatal and postnatal development.