Lutein and zeaxanthin are carotenoids. They are isomers, which means that their molecular formula is the same but the structure is different. Their chemical properties are similar, but not necessarily the same in every detail. In the eye, for instance, they are deposited in different parts of the yellow spot, which indicates slightly different functions. Both are pigments, and both have nutritional functions with proved health effects. Indeed, these two might be the most clearly beneficial carotenoids known so far, more so than the well-known beta carotene. They are very strong antioxidants, and studies show a large number of interesting effects. (The text mentions lutein or zeaxanthin separately, but that is because studies were conducted like that, and their effects may sometimes differ.)
In the skin, lutein increases hydration, lipid level, and elasticity. It protects against oxidation due to pollution and light, which both attack the skin from the outside, causing oxidation. (More on lutein and light below.)
Lutein, present in the blood serum, might retard or stop thickening of the walls of the arteries, thereby protecting from atherosclerosis, a dominant factor in the development of cardiovascular disease, and from stroke. It is still an open question whether very high doses might even reverse already present thickening of the artery walls.
Studies indicate that lutein and zeaxanthin are transferred from mother to baby through the umbilical cord and through breast-feeding, and that they are essential during pregnancy.
Numerous studies show that lutein prevents cancer. It also stimulates immunity, and that may explain why it protects from tumours.
For eye health, lutein and zeaxanthin are absolutely crucial. They are the pigments which give the "macula lutea", the yellow spot (in the retina), its colour, and they protect from so-called Age-related Macular Degeneration (AMD). Macular degeneration is a condition where the light-sensing cells in the macula lose in function and finally cease to work. It is a common cause of blindness or bad sight. The more pigment you have in your yellow spot, the better protection you have. These carotenoids protect against local oxidation, and from blue and ultraviolet light. They absorb this light, so it never reaches the retina where it would cause oxidation.
Note that certain lamps can also emit blue light, and thus contribute to the development of AMD. Most notably fluorescent ones. Light should be yellowish to be safe. All forms of bluish or "cold" light might be a danger. More on that in “Blue Light, Blindness, Sleep Disorder & Cancer “
Melanin also protects the eye. If you have blue eyes, a hundred times as much light reaches the back of the eye compared to someone with dark brown or black eyes. So AMD is more threatening to blue-eyed people than to those with darker eye pigment. But while you cannot affect your inherited eye colour, the amount of yellow pigment in the yellow spot is determined by the amount of lutein and zeaxanthin in your diet.
Attempts have been made to reverse macular degeneration on a nutritional basis (by high intake of these two carotenoids). The results are not conclusive, however promising. People have reported increased sharpness of vision and improved ability to discern colours. If you have problems with your sight, it might be worth a try.
In their capacity of being antioxidants, lutein and zeaxanthin play a role in cataract protection.
We need at least 6-10 mg lutein per day to benefit fully from it in terms of protection, more if you want to reverse an already existing problem. Dietary supplementation might be necessary to reach such a level.
Raw foods rich in lutein and/or zeaxanthin are: maize, leafy greens (as spinach), yolk, potatoes, red peppers (including paprika), red-blue-purple fruits, dill, carrots, tomatoes, oranges, kiwi, Brussels sprouts, nectarines, papaya, saffron - and dried Lycium barbarum fruit (fructus lycii), better known as goji berry. The latter, rich in zeaxanthin and poor in lutein, is used for a number of eye diseases in traditional Chinese medicine.
All carotenoids are fat-soluble, which means that intestinal presence of some dietary fat is necessary for them to be absorbed. It does not have to be much, but many foodstuffs containing them are extremely poor in fats. There is no problem if you eat them in a meal, but if you take just a separate nectarine, a carrot, or some green leaves, for example, you might have to take a teaspoon of oil or something with that, in order to provide fat. Or take a couple of nuts or some sunflower seeds, that would suffice.
(This article is based on material previously published in Meriondho Leo and in my e-book “Nutrients & Dietary Supplements”, 2019.)
Blue Light, Blindness, Sleep Disorder & Cancer
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