Carpenter K J
Department of Nutritional Sciences, University of California, Berkeley 94720-3104, USA.
J Nutr. 1998 Feb;128(2 Suppl):423S-426S. doi: 10.1093/jn/128.2.423S.
By 1824, Chevreul had demonstrated that fats were esters of glycerol and fatty acids of differing chain length. At the time, it was thought that fats could be synthesized only by the plant kingdom. However, by 1850, it had been found from balance studies that animals also could synthesize fats from carbohydrates. The caloric value of fat was determined in the 1860s and shown to be more than double that of carbohydrate. In 1907, it was shown that this was also true when fat was used as a source of energy for physical work. The special value of cod liver oil for the prevention and treatment of rickets was well known by 1850 but was not to be explained until much later.
到1824年，谢弗勒尔已经证明脂肪是甘油与不同链长脂肪酸形成的酯。当时，人们认为只有植物界能够合成脂肪。然而，到1850年，通过平衡研究发现动物也能利用碳水化合物合成脂肪。19世纪60年代确定了脂肪的热值，结果表明其热值是碳水化合物的两倍多。1907年，研究表明当脂肪用作体力活动的能量来源时也是如此。到1850年，鱼肝油对预防和治疗佝偻病的特殊价值已广为人知，但直到很久以后才得到解释。
