Eye Nutrition

By Ayomikun Nifemi Dahunsi OD.

The health of the eye is dependent on the health of the body. There are about 50 known essential nutrients for the human body, which include the vitamins and about 20 minerals. Nutrition and the eye continues to be a field of very active research and the information available can be used as a guide for advising proper dietary habits and for considering vitamin and mineral supplements, rather than as firm recommendations. Some nutrients are likely to be toxic if taken in excess and so there is an upper limit for consumption that should not be exceeded.

Vitamins are today often referred to as micronutrients. Vitamin A is essential in the formation of the retinal photoreceptor pigments and vitamin A deficiency leads to defective night vision. Vitamin A is also important in maintaining the health of the ocular surface and keratomalacia occurs when the diet is grossly deficient in vitamin A. In common with vitamins C and E, vitamin A has anti-oxidant properties. Vitamin C is secreted into the aqueous humour where it is more concentrated than in other body fluids, suggesting its particular importance to the lens. The level of vitamin C in the aqueous increases with increased dietary intake, which suggests that the lens will feel the effects of increased vitamin C intake.

The anti-oxidant vitamins A, C and E are present in green leaf foods, fruits, nuts and root vegetables. Provitamin A (beta-carotene) is present in dairy products, green plants and in yellow or orange fruits. Parsley and spinach are particularly rich sources and the best root vegetable for vitamin A is the carrot. Vitamin A is present in fruits, but fruits have a lower concentration than leaves.

Also, Zinc plays a vital role in bringing vitamin A from the liver to the retina in order to produce melanin, a protective pigment in the eyes. Impaired vision, such as poor night vision and cloudy cataracts, has been linked to zinc deficiency. For natural dietary sources of zinc, try red meat, oysters and other shellfish, and nuts and seeds. When taking zinc, copper absorption is lessened. It’s recommended that zinc be combined with copper supplements.

Lutein and Zeaxanthin are carotenoids. Carotenoids are pigments found in plants and in your retina. Supplementing these pigments helps increase their density in your retina. They also absorb high-energy blue and ultraviolet light that can damage your eyes. Lutein and zeaxanthin are the most common xanthophylls in green leafy vegetables (e.g., kale, spinach, broccoli, peas and lettuce) and egg yolks. 

Proper nutrition can have preventive and protective mechanisms for people’s overall health‚ including ocular health.

Pharmacologic doses of nutrients and supplements such as vitamins, minerals, and essential fatty acids can prevent or delay the onset of certain eye diseases.