Key nutrients for healthy vision
The eye is rich in nutrients and other dietary components that support and complement each other. Some nutrients are necessary for the basic physical structure of the eye, some for the physiology of sight, and others for protection. Nutrients within the visual system can be thought of as a hierarchy representing a complex of interacting factors: while vitamin A (retinol) is essential for the formation of visual pigments, the antioxidants vitamin E, vitamin C, lutein and zeaxanthin help to protect the lens and retina against light-induced oxidative damage, and the long-chain omega-3 fatty acid docosahexaenoic acid (DHA) enriches neural tissues including the photoreceptor cells. These nutrients are known to be important for visual development early in life, starting from the fetus through infancy to early childhood. Visual acuity gradually improves until about age four, when it is comparable to that of adults. For adults a sufficient intake of these nutrients is needed throughout the lifespan to maintain visual performance, such as the ability to adapt to low light, recover from intense light and distinguish objects from their background.
The controversy around antioxidants and prooxidants
Antioxidant research has progressed over the past decades from the initial enormous potential of antioxidants envisioned by researchers when the free radical theory of aging was proposed, through to the current reality of positive, negative, and inconsistent results from clinical trials investigating antioxidant interventions in numerous health conditions. Human physiology has turned out to be more complex than originally thought. Endogenous antioxidant defenses and antioxidant intake from exogenous dietary sources are most certainly critical factors in health and disease. However, the interplay between the effects of antioxidants and the body’s defense systems are intricate and complex, and ultimately cannot be boiled down to a simple equation stating that antioxidants are “good” and free radicals are “bad.”
A new study from Singapore suggests that increased maternal folate concentrations during late pregnancy seem to be associated with longer gestational age and a lower risk of preterm birth.
A new study from the Netherlands reports that insufficient vitamin D intake of pregnant women and their infants seems to be associated with an increased risk for positional skull deformations during infancy.