Iron deficiency is one of the most common nutrient deficiencies worldwide because iron is difficult to get and absorb in the proper amount from the diet alone (Taber's Cyclopedic Medical Dictionary).

全世界最常见的营养不足是缺铁，因为铁是很难仅通过饮食，得到和吸收（泰伯的泛的医学词典）。