DHA, whose full name is Docosahexaenic Acid, is a polyunsaturated fatty acid with 22 carbon atoms and 6 double bonds in its chemical structure. Because the first double bond is located at the position of the third carbon from the tail, it belongs to the Omega-3(ω-3 or n-3) series of fatty acids.

DHA is one of the essential fatty acids for human body. Essential fatty acids are essential to maintain the function of various tissues, and when lacking, they can cause a series of symptoms, including growth retardation, abnormal skin scales, infertility, mental retardation and so on. As an essential fatty acid, DHA plays a more significant role in enhancing memory and thinking and improving intelligence. For example, population epidemiological studies have found that people with high DHA content in their bodies have strong psychological endurance and high intellectual development index. DHA can also prevent myopia and improve vision. If a woman lacks DHA in her diet during pregnancy, it may lead to fetal blindness.

[DHA-rich food]

Deep-sea fish: tuna, tuna (yellowfin tuna), salmon (salmon), whale, seal, herring, hairy scale fish, salmon (Atlantic salmon), trout, cod, saury, herring, tuna, sardines, eels,

The DHA content in the fat of marine fish and seashells is 2.5- 100 times that of the fat of land animals and plants.

Freshwater fish: Carassius auratus, Monopterus albus and fish eggs.