Written by Jessica Patella, ND. A research study showed that participants with the highest blood levels of lutein and zeaxanthin had 42% and 41% lower risk of cataracts compared to those with the lowest levels. Factors that increase the risk of cataracts include smoking, sunlight exposure, diabetes, aging, and some pharmaceuticals.
The number of persons with cataracts in the United States is estimated to increase by 50% in the next 20 years, due to increased life expectancy (1). This is a concern because age-related cataracts are the leading cause of blindness among the elderly worldwide (2). Recent research shows blood plasma concentrations of lutein and zeaxanthin are associated with a decreased risk of cataracts in the elderly population (3).
Cataracts are a clouding of the lens in the eye that can be caused by aging, smoking, sunlight exposure, oral corticosteroids, estrogen replacement therapy and diabetes (3,4). The most common type of cataract is called a nuclear cataract and is more common in women (3).
Beta Carotenes are pre-cursors to vitamin A and found in most orange-colored fruits and vegetables. Beta-carotene intake is related to a decreased risk of nuclear cataracts (3). The most prevalent beta-carotenes in the lens of the eye are lutein and zeaxanthin (3).
The recent research included 1689 participants (559 women, 1130 men) aged 61-80 years and was conducted from 2005-2008. At baseline, blood sample were taken to determine levels of lutein and zeaxanthin. Over the four-year follow-up, 113 cases of cataracts were diagnosed (6.4%), of which 108 were nuclear cataracts.
Participants with the highest blood levels of lutein and zeaxanthin had 42% and 41% lower risk of cataracts compared to those with the lowest levels (P=0.041, P=0.046) (3). Age increased the risk of cataract by 10% (P<0.001). But oral corticosteroid use was the most important risk factor, increasing the risk of developing cataracts by 3 times (P=0.023) (3).
It is important to note that none of the participants were taking beta-carotene supplements during the study, meaning blood levels were strictly from dietary sources (3).
In conclusion, higher blood levels of lutein and zeaxanthin were associated with a decreased risk of cataracts in elderly participants. The study was strong due to the large number of participants. However, a limitation was that only one blood sample was taken at baseline. Taking multiple samples would give a more precise measurement in the future (3).
Source: Karppi, Jouni, Jari A. Laukkanen, and Sudhir Kurl. “Plasma lutein and zeaxanthin and the risk of age-related nuclear cataract among the elderly Finnish population.” British Journal of Nutrition 108, no. 1 (2012): 148-154.
© The Authors 2011
Posted March 19, 2012.
References:
- Congdon N, et al. Causes and prevalence of visual impairment among adults in the United States. Arch Ophthalmol 2004. 122: 477 – 485.
- Chiu CJ & Taylor A. Nutritional antioxidants and age-related cataract and maculopathy. Exp Eye Res 2007. 84: 229– 245.
- Karppi J, Laukkanen J, Sudhir K. Plasma lutein and zeaxanthin and the risk of age-related nuclear cataract among the elderly Finnish population. 2011 doi: 10.1017/S0007114511005332.
- Age-Related Eye Disease Study Research Group (2001) Risk factors associated with age-related nuclear and cortical cataract: a case-control study in the Age-Related Eye Disease Study, AREDS Report no. 5. Ophthalmology 108, 1400 – 1408.
