Hello Dr Is it important to give B complex with or after antibiotics to a 4yr kid? Please give me detail knowledge on this

A. Toddlers aged 1 to 3 years need 0.9 mcg of B12 per day. Kids aged 4 to 8 years need 1.2 mcg of B12 per day. Kids aged 9 to 13 need 1.8 mcg of B12 per day. Teenagers aged 14 to 18 need 2.4 mcg of B12 per day.Most healthy children don't need multivitamins if they are growing at the typical rate and eating a variety of foods. Foods are the best source of nutrients: fat, protein, carbohydrates, vitamins and minerals. Regular meals and snacks can give all the nutrients most preschoolers need.