有关部门对我国城乡人民的膳食结构调查表明,除膳食中的三大热能营养比例不合理外,最为严重的就是维生素A的明显缺乏,其程度甚至低于最低生理供给标准的50％。维生素A是维持人体健康不可缺少的重要营养成分之 A survey on the dietary structure of urban and rural people in our country shows that except for the unreasonable proportions of the three major heat-energy nutrients in the diet, the most serious one is the apparent lack of vitamin A, which is even below 50% of the minimum physiological supply standard. Vitamin A is an essential nutrient to maintain human health