Malnutrition makes your body vulnerable to a wide range of infections and diseases, some of which may affect your eyes. A lack of vitamins and minerals won't change your eye color, but it can contribute to conditions that cause a change in how your irises reflect light, which can give the appearance of a different eye color.
Your eye color comes from two types of pigment cells in your iris. Melanin provides brown color and lipochrome produces a brown-yellow hue. If you have very little of these pigments, light that hits your eyes will interact with the natural grayish color of the fibers in your irises and they will appear blue. Greater amounts of these pigments produce green and hazel, while a very dense concentration of pigment gives you deep brown eyes. Most people have pigment cells on both the front and back of their irises, but if you are one of the rare people who don't, the red color from many tiny blood vessels in the back wall of your eye may reflect back through your irises and mix with pigment on the front, which may give the appearance of violet or aqua eyes. In some cases, this reflection only appears around the outer edge of the eye, so you may have blue eyes with a brown ring around each iris.
Benign Eye Color Change
An infant's eye color usually will change as the child develops. Babies, particularly Caucasian babies, are often born with little or no pigment in their eyes, but exposure to sunlight triggers melanocytes to produce increasing amounts of pigment until the irises reach their adult color by around age 3. Iris pigmentation does not change in healthy adults, but if you have light-colored eyes, colors from your clothing or make-up may interact with the light reflected back by your irises and your eyes may appear to change color temporarily. Changes in lighting around you also can alter the way your eyes reflect light. In addition, when you are sick or under stress, your eyes may appear lighter or darker than normal due to changes in the density or distribution of the pigmentation in your irises. Scientists have not yet developed a complete understanding of this process.
Some diseases may change the distribution of pigmentation in your eye. Two types of glaucoma -- pigmentary glaucoma and exfoliation syndrome -- cause pieces of pigment from the back of the iris to flake off and become lodged in the eye's drainage canal, which raises pressure inside the eye. As the pigment flakes off, the color of your iris appears lighter. High cholesterol, or hyperlipidemia, also can change the color of your eyes. A build-up of cholesterol can manifest as a white or light-colored ring around your eyes. Changes to your diet to reduce your fat intake may help lower your cholesterol and prevent the buildup of such rings around your irises. Injury or infection also may cause a loss of pigment from the back of the iris.
Dr. Meghan Lambert of Advanced Vision Care at the Brown Center says that although there is no direct link between malnutrition and a change in the color of your iris, malnutrition can compromise your immune system, which makes you vulnerable to infection. Eye infections can lead to scarring of the cornea -- the eye's normally clear outer layer -- and this can make a dark-colored iris appear blue, although the pigmentation really doesn't change. More importantly, nutrition affects your overall eye health. Lack of vitamin A is the leading cause of preventable blindness in developing countries, according to the information website KidsHealth.org.