According to new findings published in the Journal of Nutritional Biochemistry, lutein may protect the DNA of photoreceptive cells in the retina from the harmful effects of strong light.
Japanese researchers also report that visual impairment produced by strong light exposure was attenuated in mice fed supplements of lutein.
Lutein and its market
Lutein, a nutrient found in various foods including green leafy vegetables and egg yolk, has a ten-year history in the dietary supplement market as a nutrient to reduce the risk of age-related macular degeneration (AMD), the leading cause of blindness in the over 50s.
The US is by far the most developed market for eye health products, partly due to a greater acceptance of dietary supplements, and partly due to higher levels of awareness, according to data from Frost & Sullivan.
Frost & Sullivan placed the US eye health ingredients market at $138m in 2008, with a compound annual growth rate (CAGR) of 5.3 per cent from 2008 to 2015. The European market was valued at $43.4m in 2007 with a CAGR of 10.5 per cent from 2007 to 2014.
For the new study the researchers divided mice into two groups: One group was fed normal chow and the second group had their chow supplemented with 0.1 percent lutein (provided by Wakasa Seikatsu Co., Ltd., Japan). Animals were fed the diets for 10 days before being exposed to light.
Results showed that lutein supplementation was associated with a reduction in a range of detrimental effects associated with light exposure, including visual impairment, and a thinning of the layer of photoreceptor cells.
In addition, the researchers note that a marker of DNA damage was up-regulated in the normal chow-fed animals, but this was suppressed in the lutein fed animals.
“Therefore, lutein induced […] DNA repair, which could suppress DNA damage and photoreceptor cell apoptosis.
“Lutein reduced light-induced oxidative stress in the retina, which might contribute to promote DNA repair. The lutein-supplemented diet attenuated light-induced visual impairment by protecting the photoreceptor cells' DNA,” they said.
Looking beyond the eyes
“Although lutein has been applied as a dietary supplement for chronic diseases, such as AMD, it may have a chance to be involved as a preventive medicine for acute diseases in the future,” wrote the authors.
“Moreover, elucidating the molecular mechanism of lutein's effect on light-induced photoreceptor cell apoptosis might also be helpful for analyzing lutein's effect on the photodamage in other organs.
“In the skin, lutein is believed to protect against edema and hyperplasia after UV exposure. The present study will help understand its molecular mechanism,” the concluded.
Source: Journal of Nutritional Biochemistry
Published online ahead of print, doi: 10.1016/j.jnutbio.2011.01.006
“Biological role of lutein in the light-induced retinal degeneration”
Authors: Mariko Sasaki, Kenya Yuki, Toshihide Kurihara, Seiji Miyake, Kosuke Noda, Saori Kobayashi, Susumu Ishida, Kazuo Tsubota, Yoko Ozawa