The following advertisements are in line with scientific facts: () A. This brand of eight-treasure porridge is refined from lotus seeds, starch, etc., and it does not contain sugar. B. This beverage does not contain sugar. A, the essence of starch is polysaccharide, A is wrong;

B, the substances in the beverage are all chemical substances, and B is wrong;

C, cod liver oil (rich in vitamin D), can promote the absorption of calcium and phosphorus in the small intestine and help the baby's bone development, C is correct;

D, the essence of antibody is protein, which can only be injected, not taken orally, D is wrong.

So choose: C.