What is DHA? It's short for DocosaHexanoic Acid, an important omega-3 fatty acid and a building block of the brain, important for its healthy structure and function. DHA is found in breast milk and is an important nutrient and in formulas. So you've been giving her DHA all along. But because her brain is still rapidly growing until age three and will never grow this quickly again, it's important that DHA remain a part of her diet.