poisoning has been regarded as the first killer of intelligence development of children. The excessive content of lead inside the body can cause many problems, such as hyperactivity, attention-deficit disorder, impulse of motion, developmental delay of language skills and so on. 

Lead can enter the human body through three mediums: the digestive tract, the respiratory tract and the skin. In our daily life, the main sources of lead mainly include car exhaust gas, home decoration and toys for children. Among these three sources, car exhaust contains the largest amount of lead. Many materials of home decoration contain abundant lead, such as pigment used to paint the wall and house furnishings. Cast-iron tap-water pipes also contain a large amount of lead. Toys for children contain a lot of lead if they are painted. When the children bite these toys, lead contained in toys can enter the body through the digestive tract. In addition, some kinds of cosmetics for whitening also contain lead.

When a large amount of lead is absorbed into the human body, blood lead inside the human body can be increased. Therefore, it is important for people, especially children, to discharge excessive lead from the body in time. People should live far from main roads and should not use paint to decorate their houses. When people buy toys for children, they should buy the ones which are not painted. In addition, parents can help children solve the problem of lead poisoning by providing the foods which can remove lead from the human body.

The absorption mediums of lead always compete with those of calcium, iron, zinc and selenium. If the foods eaten by children contain abundant calcium, iron, zinc or selenium, the absorption content of lead by the human body can be reduced. Lean meat and black sesame contain rich iron, and nut and marine products contain abundant zinc. Protein contained in milk can react with lead inside the human body to produce a kind of insoluble compound, which can decrease the amount of lead absorbed by the human body. Eggs, fish, meat and vegetables containing abundant vitamin C like rape, cabbage and balsam pear can help children discharge lead from the body. Kelp is also a kind of useful food to eliminate lead for children. and alginic acid contained in kelp can help children discharge lead from the body. In addition, green tea contains tea polyphenol which can accelerate the discharge of toxic substances including lead from the human body.