The better effect of oral calcium tablets for 12 year old children are calcium carbonate or calcium lactate, then children must be supplemented with vitamin D at the same time as oral calcium to ensure the reasonable absorption of calcium. You can take vitamin D medication orally and also sun exposure at the same time. The skin is more conducive to the synthesis of vitamin D after sun exposure, which is an effective way to absorb vitamin D, thus facilitating the absorption of calcium in the body. In addition to calcium supplementation, if children want to achieve a good effect of calcium supplementation, they can also eat more calcium-containing foods in their daily lives, such as eating more seafood, shrimp, drinking more milk, eating more peanuts and nuts, etc. Food and medicine together to ensure that children can more beneficial calcium supplementation.