Which nutrients benefit your sight? Naturopath Siobhan Jordan reveals how to eat for healthy eyes.
Healthy eyes rely on a wide range of nutrients and recent research sheds light on the following areas:
- The roles specific nutrients play in the numerous functions of the eyes
- How the eyes may be affected when nutritional deficiencies occur; and
- Which nutrients may assist in the management and/or prevention of eye disorders
Vitamin A is the generic term used to encompass a range of related compounds. These compounds can be divided into two key groups:
(1) Preformed vitamin A (retinoids), which are found only in foods of animal origin. An example is retinol.
(2) Provitamin A (carotenoids), found predominantly in food sources of plant origin. Examples of these include betacarotene, lutein and zeaxanthin 
Preformed vitamin A may protect the photoreceptor membranes in the eye against oxidative damage and is known to have a role in the repair of cells that have been injured by this process .
Vitamin A deficiency is associated with night blindness and is the primary cause of preventable blindness in South-East Asian children .
The carotenoids lutein and zeaxanthin are found in high concentrations in the retina of the eye, including the macula. In the macula, these function to absorb blue light. Light- associated oxidative damage is believed to play a role in the development of age-related eye conditions, and high dietary intakes of lutein and zeaxanthin are linked to a lower risk of these .
FOOD SOURCES: Vitamin A is found in liver, dairy products and eggs; lutein and zeaxanthin are found in foods such as spinach, kale, collards and broccoli .
Carotenoids are best absorbed when taken with dietary fats . If you’re eating a salad with carrots, spinach, and pumpkin for example, have it with a dressing containing oil eg. olive oil.
Vitamin C is found in high concentrations in the tissues of the eye. Deficiencies can result in numerous eye problems, including bleeding in the lids and conjunctiva .
Trials such as the age-related eye disease study (AREDS) reveal positive eye health outcomes when using supplemental antioxidants including vitamin C.
FOOD SOURCES: blackcurrants, strawberries, capsicum and citrus fruits 
Vitamin E is an important antioxidant and in the retina, vitamin E is thought to protect vitamin A from oxidative degradation . Vitamin E also functions synergistically with carotenoids to manage free radicals . In a state of vitamin E deficiency, changes suggestive of oxidative damage are seen in some structures within the eye .
FOOD SOURCES: vegetable, nut and seed oils; spinach and sweet potatoes 
Zinc is found in a number of tissues within the eye, where it is thought to play a protective role against age-related wear and tear . Zinc acts an antioxidant and also assists in the transport and metabolism of vitamin A, another key eye health nutrient .
Zinc deficiency can result in night blindness and/or changes in dark adaptation . It may also play a role in the development of age-related eye conditions . In addition, AREDS found that supplemental zinc, in combination with other antioxidants, significantly decreased the risk of eye age-related eye conditions worsening to an advanced stage .
FOOD SOURCES: eggs, seafood, meats, nuts and legumes 
The above provides a brief introduction to some of the nutrients critical to eye health. Many others are also essential to healthy eyes and with continued research, no doubt further discoveries will be made.
Keep your eyes peeled!
Top foods for healthy eyes
Spinach great source of lutein, zeaxanthin and vitamin E
Eggs contain vitamin A and zinc
Nuts & seeds provide vitamin E and zinc
Blackcurrants excellent source of vitamin C
1. Eperjesi, Frank and Beatty, Stephen (editors). Nutrition and the eye a practical approach. Philadelphia: Elsevier Butterworth-Heinemann, 2006
2. Higdon, Jane. An evidenced-based approach to dietary phytochemicals. New York: Thieme, 2007
3. Braun, Lesley and Cohen, Marc. Herbs and natural supplements: an evidenced-based guide, second edition. Marrickville: Elsevier, 2007