Soothing our eyes and lifting our spirits
James Allen Olson (1924-2000), a nutritional biochemist and professor of Iowa State University, believed that every scientific presentation at Experimental Biology deserved “a good question.” The question on Friday afternoon was whether or not to continue on with a special session held in honor of his memory.
It was an event that would highlight carotenoid research and was organized by the American Society for Nutrition’s Carotenoids Research Interaction Group (CARIG), a research interest group Professor Olson held dear and helped to found.
Despite the recent happenings of Boston, low attendance, and a few missing speakers, the event took place as planned at the Westin Boston Waterfront. “I’m glad that we decided to go ahead even though we didn’t have the plenary speaker,” said Loredana Quadro, an assistant professor of food science at Rutgers University, who chaired the session.
The role of carotenoids in the brain and eyes was the intended topic of the session. However, the brain aspect could not be covered because the two speakers who were supposed to discuss it weren’t able to make the event due to the Boston lockdown. The three speakers put the spotlight of the afternoon on vision health.
Dr. Lewis Rubin, a professor of medicine of the University of South Florida, discussed the role of carotenoids in the retina and in retinopathies. The majority of the research in retinopathies revolves around age-related macular degeneration and, to a lesser extent, diabetic retinopathy, he said. However, another condition that is not as well studied is retinopathy of prematurity.
Retinopathy of prematurity has a similar pathology as diabetic retinopathy, except that it involves abnormal blood vessel development in the retina of the eye of a premature infant. The disease is a well-known cause of blindness in children around the world and, in particular, Latin America. Stevie Wonder is a famous example of someone who suffered from this disease, who would not have suffered from it had he been born in the U.S. today.
Dr. Rubin’s recent research focused on dietary carotenoids, and their importance in retinal health and maturation, as well as decreasing inflammation in preterm infants. Interestingly, his findings suggest that supplementation of carotenoids (specifically lutein) could reduce the severity of retinopathy of prematurity.
The talk that followed was given by Sherry Tanumihardjo, who manages a research and outreach team at the University of Wisconsin-Madison. The team has conducted studies in the United States and several developing countries including Zambia. She discussed current efforts in biofortification of food including orange-colored maize with beta-carotene in Zambian children.
Maize, being a staple in Zambia, represents an important method for providing beta-carotene to these children. The fortification is ideal for supporting the development of these children and supporting their immune systems to adequately protect against several types of infectious diseases.
The third speaker was Matthew Toomey, of Washington University in St. Louis, who discussed his research on avian retinal carotenoid accumulation. The focus of his studies has been in bird species such as chickens and zebra finches and dietary carotenoids supplied in their diet from fruits and berries.
Interestingly, these birds have a “broad palette of pathways of carotenoid metabolism”. When modified, the way the carotenoids are localized in photoreceptor cells, called “cones” is different as well. For example, zeaxanthin can be cleaved down and/or modified by adding ketone groups that allow for absorption of longer or shorter wavelengths.
The modification allows the birds to have a narrowed spectral sensitivity that facilitates color discrimination more precisely. Humans, in contrast, have only three types of cones (red, green and blue sensitive cones) with a lot of overlap allowing for a more broad spectral sensitivity. Improvement in our understanding of these pathways could open our eyes to how birds evolved the ability to develop the unique colors of their feathers as well as a range of functions of vision.
Each of the presentations on vision and the fascinating one by Toomey on birds, seemed fitting to the memory of Olson, who with Norman Krinsky once coauthored a serial review in 1995 in FASEB, that opened with this introduction:
“Carotenoids in nature soothe our eyes and lift our spirits, whether in the petals of flowers, in the plumage of birds, or in the delicate hues of some fruits and vegetables.”
Photo credit: Wiki