Babies with severe calcium deficiency, how should they supplement calcium? Is it necessary to take cod liver oil at the same time? What are the considerations for the timing and method of calcium supplementation? What should you eat to supplement calcium? Do you need to take cod liver oil simultaneously? When should cod liver oil be taken in relation to calcium supplementation? Can calcium be taken on an empty stomach? How soon after breastfeeding should calcium be supplemented? The child is breastfed, and has previously used Jiajia Calcium, but now the doctor recommends using calcium gluconate. However, it is unclear whether cod liver oil still needs to be taken. Assistance is needed with this matter.