2. Calcium deficiency leads to brittle bones and low hematopoietic capacity. 3, iodine deficiency is easy to get big neck disease, which hinders the secretion of thyroid hormone. 4, zinc-deficient hair is easy to fall off and bald. It is not good for the skin, and dermatitis will occur due to zinc deficiency. Zinc plays an important role in regulating metabolism, especially the synthesis of protein and the production and secretion of growth factors.