Researchers found that those with higher sunlight exposure during the day had significantly higher levels of macular pigment, which prevents age-related vision loss.
Summer is a sight for sore eyes in more ways than one. A study by the Nutrition Research Centre Ireland has found that diet and daytime exposure to sunlight are the two key factors behind good eye health.
Based on a comparison between Mexican and Irish population samples, the study found that Mexicans had significantly higher levels of macular pigment.
Low levels of this pigment have been proposed to be a risk factor for macular degeneration, the leading cause of significant vision loss usually found in those over 55. This pigment is also known to protect the retina from damage by absorbing harmful blue light.
Led by Dr Marina Green, the team of researchers found that sunlight exposure during the day is a determinant of the concentrations of macular pigment.
Subjects with daily sunlight exposure of more than 50pc were found to have significantly higher amounts of the pigment than those with less than 50pc.
Macular pigment exhibits a characteristic yellow pigmentation and is principally composed of the carotenoids meso-zeaxanthin, lutein, and zeaxanthin. Carotenoids are the pigments that give pumpkins, carrots, corn and tomatoes their colour.
Researchers found that the carotenoids lutein and zeaxanthin were also higher in the Mexican study sample compared with an Irish sample. This could suggest that there are benefits to be had from consuming lutein and zeaxanthin-rich foods, especially in consideration of conditions such as diabetes. Previous research found that those with diabetes have about half as much macular pigment as healthy individuals.
“The new data from a Mexican sample provides evidence of the multifactorial interactions and environmental determinants of macular pigment such as sunlight exposure and dietary patterns. These findings will be essential for future studies for eye health, visual function and ocular pathology,” Green said.
The study was published by online journal Investigative Ophthalmology & Visual Science (IOVS).
Prof John Nolan, director of the Nutrition Research Centre Ireland, which is based in Waterford Institute of Technology, said that understanding the main determinants of the protective macular pigment at the back of the eye is one of the challenges in ophthalmology research.
“Specifically, we learn how light exposure is a key determinant of the protective macular pigment, a finding that highlights further the important role this pigment plays for vision and retinal health,” Nolan said.
The research was conducted in partnership with Industrial Orgánica, a Mexican company that produces carotenoids from natural sources, and medtech company Heidelberg Engineering.