Factors affecting the absorption of vitamin A
 1, small intestine, bile, vitamin A is necessary for emulsification.
 2. Dietary fat, adequate vitamin A can promote fat absorption.
 3. Antioxidants such as vitamin E and lecithin, etc., conducive to their absorption.
 4. Taking mineral oil, and intestinal parasites are not conducive to vitamin A absorption.
 5. Vitamin C has damaging effects of vitamin A. Especially after large doses of vitamin c, will promote the excretion of vitamin A, so, in large doses of vitamin C at the same time, we must pay attention to dose of vitamin A should be sufficient.

 Excessive vitamin A intake of the clinical manifestations

 50000IU daily intake for adults over several months can cause poisoning. If the intake of children in one day than 18500IU would cause poisoning. Main performance: As the enhanced osteoclast activity, leading to bone demineralization, bone fragility, growth inhibition, the long bones thicker and bone and joint pain; skin dry, itchy, scaly skin, skin rash, peeling, hair loss, (toe ) A brittle; irritability, fatigue, headache, nausea, vomiting, muscle weakness, restlessness. Loss of appetite, abdominal pain, diarrhea, hepatosplenomegaly, jaundice; decrease in blood hemoglobin and potassium, coagulation time, easy bleeding.