Similac Gold HMO 4 is designed for kids from 3 years and above. HMO (2-fl) HMOs are the third most abundant solid component in human milk. Similac Gold HMO 4 contains natural vitamin E, DHA, lutein, arachidonic acid, omega 3 & 6, taurine, zinc, iron, prebiotics, nucleotides, vitamin A, C, D, B6, and B12. Vitamin A, C, D, B6, and B12 contribute to the normal function of the immune system. HMOs act as decoys that prevent bad bacteria from attaching to gut cells thus, preventing them from entering your child's system. Some HMOs are also absorbed into the bloodstream where they can trigger immune cells to release protective factors, regulate allergies or infections in your child. Thus, HMOs deliver an immunity boost beyond the gut.