Through experiments, it is found that soft-shell foods such as shrimp contain a large number of high-concentration-pentavalent arsenic compounds. This substance has no toxic effect on the body after being ingested. However, after taking vitamin C, the original nontoxic pentavalent arsenic (namely arsenic anhydride, also known as arsenic pentoxide) becomes toxic trivalent arsenic (namely arsenic anhydride), also known as arsenic trioxide, and its chemical formula is (As2O5). This is ... For the sake of prudence, shrimp should not be eaten during taking vitamin C.

Vitamin C is a water-soluble vitamin. Among all vitamins, vitamin C is the most unstable. It is easy to be destroyed during storage, processing and cooking. It is also easily oxidized and decomposed. After the fruit is cut, it gradually turns yellow and brown, and the vegetables are overcooked and turned black, all of which indicate that vitamin C is oxidized. The vitamin C contained in C tablets or foods of sensitive people is the same.