More than 25% of the nutrition your body absorbs goes to feed the visual system. The visual system consumes one third of all the oxygen that you take in. Metabolism in the eyes is faster than anywhere else in the body. The concentration of vitamin C and other important nutrients is higher in the healthy eye than almost anywhere else in the body.

It’s not surprising, then, that proper nutrition plays an extremely important role in preventing and treating all of the common eye problems — myopia, presbyopia, cataract, macular degeneration and glaucoma. Nutrition's exact role is becoming more and more clear. Some facts are already well documented and pioneering doctors are uncovering other directions that are very promising.

Before we can discuss each eye problem in greater detail, it’s important to keep in mind some general nutritional information:

1. Proper balance is important. The body does not use each vitamin and mineral in isolation. The absence of one may affect the body’s ability to use another. For example, proper amounts of magnesium and vitamin D are needed in order to absorb calcium efficiently and completely. And, without adequate levels of zinc, the body cannot utilize all the vitamin A it receives.
2. The Recommended Daily Allowances (RDA) suggested for most vitamins and minerals are most often only the minimum levels needed to prevent deficiencies. However, visual health – and total body health - most probably requires supplement levels that are significantly higher than the RDA. Cataract prevention, for example, may require the intake of vitamin C at a level 15 times greater than the RDA.
3. In today’s society, it is probably not realistic to expect to get all of our nutrients from food alone. No matter how wholesome and pure our diet might be, there are other factors that affect the nutrient content of the food we eat. How food is grown, how it is stored and how it is cooked all affect its nutrient value. Besides, the amount of nutrients a particular food is supposed to contain is measured under ideal laboratory conditions, which probably don’t reflect the food you are actually eating. Most of us have long known that carrots and vitamin A are supposed to be good for the eyes. Even so, 68% of the population is deficient in vitamin A. Over the last 50 years, the carrot has lost 75% of its magnesium content, 48% of its calcium, 46% of its iron and 75% of its copper. Modern farming methods have depleted the soil of trace minerals vital to our health, such as selenium, manganese and vanadium. Even calcium and vitamin C are found in lower levels in fruits and vegetables now than they were 50 years ago.
4. On the other hand, “popping” vitamin pills is no substitute for a wholesome diet. The body loses a significant amount of nutrients depending on the kind of food we consume. For example, we lose the trace mineral chromium as our body tries to absorb white sugar. And caffeine, refined flour, medication and preservatives also leach trace minerals and vitamins from our system. Also, there may be as yet undiscovered vitamins and minerals in food that someday will prove to be very important to our health.
5. Age, activity level and stress affect what your body needs and how well your body can absorb and use what nutrients it does get.