A comparison of eye-health nutrients, lutein (L)/zeaxanthin (Z) Intakes and L/Z rich food choices between college students living in Los Angeles and Taiwan.(Los Angeles, California)(Report)

Lutein and zeaxanthin (L/Z) were related to macular health. With respect to increasing life expectancy, age-related macular disease (AMD) has become a concern on public health. The objective was to investigate dietary L/Z intake and its related food preference in populations living in different areas. A three-day dietary record and a supplement survey were designed to obtain data. A non-randomized, biased sampling of 240 college students were recruited in this study, 137 of them enrolled in California State University, Los Angeles (LA) and the other 93 were in China Medical University in Taichung, Taiwan (TW). LA consisted of 101 females and 36 males and TW consisted of 71 females and 22 males. LA and TW consumed average 4149.4 [+ or -] 467.5 and 4994.2 [+ or -] 533.4 mcg of L/Z, respectively. The outcome revealed that there was neither significant difference on dietary L/Z intake nor on the use of L/Z supplement between these two populations. It is noteworthy that although the food preferences related to L/Z intake were quite distinct between groups, yet the total intakes of L/Z were found to be lower than the recommended intake (L/Z) of 6000 mcg/day. The result indicated that more nutritional education regarding these two eye-health nutrients should be provided to the general public to prevent AMD.

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Age-related macular degeneration (AMD) is a devastating deterioration happening on macula, the posterior area of retina, controlling the fine, detailed and sharp vision. AMD is the leading cause of blindness in older people in the Western World (Congdon et al., 2004; Munoz et al., 2000; Wang, Foran & Mitchell., 2000; Weih, VanNewkirk, McCarty & Taylor, 2000; klaver et al., 1998; Klein, Rowland & Harris, 1995). With the increasing life expectancy of most populations, the incidence and prevalence of AMD is inevitably increasing worldwide. The Age-related Eye Disease Study (AREDS) Research Group announces that approximately 8 million U.S. people older than 55 years old have the potential to develop advanced AMD within 5 years and will render a public health impact (Bressler et al., 2003). The Eye Disease Prevalence Research Group proclaims that it is currently affecting more than 1.75 million individuals in the United States and with the rapid increase of aging population in the U.S., 3 million of AMD cases are expected by 2020 (Friedman et al., 2004).

Most epidemiological researches support the belief that dietary intake plays a decisive role in the development of AMD (Seddon & Chen, 2004; AREDS, 2001; Snodderly, 1995). A growing body of evidence indicates that lutien and zeaxanthin (L/Z) are two most crucial carotenoids for macular health (Hammond, Wooten & Snodderly, 1998; Hammond & Wooten, 2005). L/Z is named as Macular Pigments (MP) (Snodderly, Auran & Delori, 1984) because they are 5 fold higher concentrations in the macular retina than in the peripheral retina and account for the yellow color of the macula.

AMD is varied with geographic distribution and ethnic groups (Klein, Peto, Bird & Vannewkirk, 2004). In Asia, the World Health Organization (WHO) estimates approximately 20 million Aisans are blind (Thylefors, Negrel, Pararajasegaram & Dadzie, 1995). Instead of AMD, the main causes of blindness in Asians are found to be cataract and undercorrected refractive errors in most studies (Wong, Loon & Saw, 2006). Compared with that AMD accounts for 70% of blind cases and 33% of low vision cases among European-descendents (Munoz et al., 2000), AMD appears to play a minor role in Chinese people for blindness (Xu et al., 2006; Wang, Xu & Jonas, 2006). Whereas in Shihpai Eye Study conducted in Taiwan, retinal diseases (AMD and other retinal or choroidal diseases) serve the leading cause of blindness for Taiwanese (Hsu, Cheng, Liu & Tsai, 2004). This might be a strong indication that westernized diet, physically inactive lifestyles, and increasing life expectancy (Department of Statistics Ministry of the Interior, Taipei, Taiwan, 2006) have brought different eye epidemics in Taiwan. Since MP is exclusive of dietary source (Malinow, Feeney-Burns, Peterson, Klein & Neuringer, 1980), it is noteworthy to probe L/Z dietary consumption in Taiwanese. Although AMD mostly occurs after 65 years old but relative damages are accumulated from younger ages. It is known that L/Z are two most important carotenoids for macular health. The purpose of this study is to examine the dietary L/Z intake and related food preference in college students living in Los Angeles (LA) and in Taiwan (TW).

Methods

Human Subjects