If you live in North America, you can expect to see fireworks this weekend as both Canadians and Americans will be celebrating. Several years ago, my wife and I were flying across the US on July 4th and we could see fireworks below our plane as it descended into Newark airport. We were awed by the contrasting explosions of bright colors against the darkening skies below us. Our visual acuity was aided by xanthophyll carotenoids concentrated in the macula of the retina.
Entries filed under 'Eye health'
It is March, National Nutrition Month, and the campaign created by the Academy of Nutrition and Dietetics, is in full swing. When it comes to making healthy choices, the focus is often on changing dietary patterns to reduce fat, sodium, and sugar intake. Makes sense when the prevalence of obesity hasn’t changed between 2003-2004 and 2011-2012 and 78.6 million American adults are obese.
Healthy eating involves more than an awareness of satiety signals to manage weight. Specialized cells in our body, like our eyes, require specific nutrients. Of 60 carotenoids in our diet, it is lutein and zeaxanthin that are concentrated in the center of the eye, in the macula where the optic nerve exits to the brain.
Randomized, double-blind, controlled clinical trials are seen as the gold standard for biomedical research for proving that a given intervention causes a certain result. However, there are a few issues with testing interventions for chronic diseases that begin to develop decades before the clinical disease. One example of this is age-related macular degeneration (AMD). How can we adequately test the relationship?
Age-related macular degeneration (AMD) is the leading cause of visual impairment and blindness as people age. Two large RCTs (AREDS and AREDS2) have demonstrated that increased consumption of antioxidant nutrients (vitamins C, E, zinc, copper, beta-carotene, lutein, zeaxanthin) can significantly decrease the progression of AMD by ~27%.
The CARED study measured pigment density (MPOD) of lutein and zeaxanthin in the macula of the retina of 1,803 individuals.
In nutrition we depend on large clinical trials to answer important questions about the efficacy of nutrients. These studies are often designed to answer a single question – does vitamin D reduce fracture incidence? Do antioxidants prevent the progression of eye disease? When we try to answer questions other than what a study was designed to answer, it feels like we’re trying to put a square peg into a round hole. Sure, we can get it to fit, but does that mean it’s the right fit?