Why should we consider waiting until a child reaches age 4 to start giving a multivitamin supplement?

Not sure.: I have my patients start multivitamins at 1 year of age or earlier if they are breast fed. That is also because there is no fluoride in the water in NJ and we start fluoride supplementation here at the age of 6 months. Some docs prescribe fluoride alone, but most do a multivitamin with fluoride (in NJ). If I were in another state, I would still recommend the vitamins.