Schalch W
Vitamins & Fine Chemical Division, F. Hoffmann - La Roche, Basel, Switzerland.
EXS. 1992;62:280-98. doi: 10.1007/978-3-0348-7460-1_29.
Two of the circa 600 naturally occurring carotenoids, zeaxanthin and lutein, the major carotenoids of maize and melon respectively, are the constituents of the macula lutea, the yellow spot in the macula, the central part of the retina in primates and humans. Of the circa ten carotenoids found in the blood these two are specifically concentrated in this area, which is responsible for sharp and detailed vision. This paper reviews the ideas that this concentration of dietary carotenoids in the macula is not accidental, but that their presence may prevent or limit damage due to their physicochemical properties and their capability to quench oxygen free radicals and singlet oxygen, which are generated in the retina as a consequence of the simultaneous presence of light and oxygen. Additionally, in vitro and in vivo animal experiments are reviewed as well as observational and epidemiological data in humans. These show that there is enough circumstantial evidence for a protective role of carotenoids in the retina to justify further research. Some emphasis will be put on age-related macular degeneration (AMD), a multifactorial degenerative retinal disease for which the exposure to light and thus photochemical damage has been suggested as one of the etiological factors. Recent attempts at nutritional intervention in this condition will also be reviewed.
在大约600种天然存在的类胡萝卜素中，玉米黄质和叶黄素分别是玉米和甜瓜中的主要类胡萝卜素，它们是黄斑的组成成分，黄斑是灵长类动物和人类视网膜中央部分黄斑区的黄色斑点。在血液中发现的大约十种类胡萝卜素中，这两种特别集中在这个区域，该区域负责敏锐和细致的视觉。本文回顾了以下观点：黄斑中膳食类胡萝卜素的这种集中并非偶然，而是由于它们的物理化学性质以及淬灭氧自由基和单线态氧的能力，它们的存在可能会预防或限制损伤，这些自由基和单线态氧是由于光和氧同时存在而在视网膜中产生的。此外，还回顾了体外和体内动物实验以及人类的观察和流行病学数据。这些表明，有足够的间接证据证明类胡萝卜素在视网膜中具有保护作用，值得进一步研究。将重点关注年龄相关性黄斑变性（AMD），这是一种多因素退行性视网膜疾病，其中光暴露以及由此产生的光化学损伤被认为是病因之一。还将回顾最近针对这种情况进行营养干预的尝试。
