Zeaxanthin is a carotenoid amalgamation and an antioxidant present in the retina of the eye. This carotenoid is responsible for preventing macular degeneration - a major reason for loss of vision in aged people. The concentration of zeaxanthin in macula, which constitutes the middle portion of the retina, is higher compared to the presence of lutein, another associated compound in the eye. Lately, researches conducted on zeaxanthin have attracted the interest of people, as it has been established that this antioxidant carotenoid has a significant role in maintaining the health of our eyes, especially among the older people. Regular use of this compound not only helps to avoid blindness due to macular degeneration, but also prevents cataracts.

In fact, zeaxanthin functions in the eye in several different manners. While the carotenoid compound saves the eyes from photo damage by means of screening out particular types of light, it also shields the eyes from oxidation - one of the widespread reasons for eye damage owing to advancing age. In addition, zeaxanthin is also said to be associated with the circulatory well-being in the eyes because in the absence of regular blood circulation, the eyes become susceptible to contagions and various kinds of impairment.

Actually, the macula in the retina of the eye is a minute indentation that helps us to see in a discern manner. When the macula is harmed or impaired, it results in hazy eyesight or formation of a dark speck in the area of vision. Ultimately, such damages may result in total loss of central vision or partial blindness making reading, operating a computer or driving virtually impossible. While macular degeneration cannot still be cured, surgeries may help to retard the development of the condition in a number of instances. Researches on the subject have shown that though the free radicals from the sun's ultraviolet rays do not cause macular degeneration, they certainly add to worsening the condition of the eyes owing to the malady. Researches have also found that people whose bloodstream contains a low intensity of antioxidants are usually easy victims of macular degeneration.

While macular degeneration is an irreversible condition, people may be optimist from the fact that there are a number of carotenoids that seem to save our eyes from any damage due to this malady. Findings of a research undertaken on the subject in 1994 demonstrated that people who consumed foods containing the maximum quantities of the carotenoids zeaxanthin and lutein faced the minimum risk of suffering from macular degeneration. The research further hinted that consuming food containing high amounts of the antioxidant carotenoid zeaxanthin is not only helpful because the carotenoid shields the macula by obstructing the actions of free radicals like peroxide, but also protects the cell walls from any harm caused by the free radicals. Several plants or plant products enclose high amounts of zeaxanthin and some of them include chicory leaf, watercress, beet greens, Swiss chard and okra. People who do not habitually consume any of these foods ought to seriously think about taking dietary supplements containing carotenoids zeaxanthin and lutein or any of the preparations containing zeaxanthin that are intended to augment eyesight.

Since zeaxanthin possesses antioxidant features, consumption of foods, supplements or formulas containing this carotenoid may also help in guarding against different types of cancer, especially those that develop due to the harmful effects of the free radicals. In effect, some initial researches on the zeaxanthin have demonstrated this antioxidant carotenoid has the aptitude to inhibit the pace of development of cancer cells.

Signs of deficiency

Several researches conducted on zeaxanthin and lutein have established that at any rate insufficient consumption of these carotenoids usually do not result in any ailments or lead to deteriorating health condition on a short-term basis. However, on a continuing or long-term basis, deficiency of these two vital carotenoids have been found to be related to chronic ailments, such as heart diseases and a variety of cancers. Findings of several studies have shown that the free radicals, especially those from the ultraviolet rays of the sun, are among the several causes responsible for several ailments when there is a deficiency of these two carotenoids in the body. In fact, several studies have hinted people taking diets that contain too less of zeaxanthin and lutein generally become vulnerable to the harmful effects of the free radicals. Consequently, if an individual takes diets possessing insufficient amounts of these two carotenoids over a prolonged period of time, they are likely to be affected by tissue damage caused by the actions of the free radicals. This, in turn, enhances the risks of developing heart ailments and different types of cancers.

Signs of toxicity

Unlike in many other cases, excessive consumption of foods, supplements or formulas containing carotenoids is absolutely safe and it does not result in any noxious after effects. This is the main reason why the Institute of Medicine at the National Academy of Sciences has not set up any Tolerable Upper Intake Level (UL) for carotenoids when it evaluated these chemicals in 2000. On the contrary, most other substances have a fixed UL, as excessive consumption of those foods may usually cause adverse side effects.

Aspects affecting performance

For appropriate assimilation of carotenoids like zeaxanthin and lutein into the body by means of the digestive tract presence of dietary fat is essential. This is primarily owing to the fact that these carotenoids are fat soluble compounds. As a result, the amount of carotenoids taken in by a person may be harmed or rendered useless to a great extent if he or she takes a diet that contains too less fat or if the individual is suffering from any ailment that affects or lowers the capability of the body to assimilate dietary fat. Maladies like Crohn's disease (a continuing disorder that results in inflammation of the digestive tract), cystic fibrosis (a hereditary chronic disease of the exocrine glands), pancreatic enzyme deficiency, removal of some or all parts of the stomach through surgery, liver problems and gallbladder ailments often decrease the body's ability to assimilate dietary fat.

These days numerous teenagers and youngsters do not consume sufficient amounts of fresh vegetables and fruits and as a result suffer from insufficiency of carotenoids like zeaxanthin and lutein enclosed in high proportions in fruits and vegetables. In addition, people who smoke cigarettes or consume plenty of alcoholic beverages also suffer from carotenoid deficiency and usually have a lower intensity of zeaxanthin and lutein in their bloodstream. Keeping statistics in view, it has been found that alcoholics and smokers usually consume very little food that encloses the vital carotenoids zeaxanthin and lutein. Moreover, scientists are of the view that cigarette smoke is harmful for carotenoids as it obliterates these vital compounds from the bloodstream. Here is a word of caution. If any individual is a regular smoker or drinker and intends to take dietary supplements containing carotenoids, it is essential that they take them with prudence.

Interactions between drugs and nutrients

Some medications are known to interact with carotenoids and, hence, they should never be used concurrently. For instance, drugs used to lower cholesterol levels that are denoted as bile acid sequestrants and include Colestid, Cholestyramine and Colestipol actually diminish the intensity of carotenoids in the bloodstream. Apart from these, margarines that are enhanced with the addition of plant sterols like Take Control and Benecol are likely to reduce the assimilation of carotenoids into the body through the digestive tract. In addition, Olestra, a substitute of fat that is used in snacks, is also likely to reduce the assimilation of carotenoids into the body.

Status of health

As discussed above, carotenoids like zeaxanthin and lutein are beneficial for the eye and help to protect from macular degeneration that often leads to loss of vision, especially in elderly people. In addition, carotenoids are essential for our body to sustain our health as well as to protect us from different diseases. Carotenoids have a major function in the prevention as well as treatment of several health conditions, some of which are mentioned below.