Infants under 6 months of age do not need DHA supplementation, while infants over 6 months of age can take appropriate DHA supplementation by taking some DHA capsules or eating more deep-sea fish. DHA is an unsaturated fatty acid, an essential nutrient for brain and optic nerve development. Breastfed babies under six months of age do not need to take DHA supplements because breast milk contains a large amount of DHA, and for artificially fed babies, DHA is added to the milk formula, so there is no need to take additional supplements. For preterm babies, low-birth-weight babies or those with hypoxic-ischemic encephalopathy and children over six months old, DHA supplementation is needed for brain development, which can be supplemented by DHA capsules, deep-sea fish, and baby food with added DHA. The adverse effects of overdose of DHA are not clear, for people with coagulation disorders can not be supplemented with DHA, the use of which should be carried out under the guidance of a doctor to avoid unauthorized supplementation.