Lutein and astaxanthin in caring for eye health

Every day our eyes are exposed to the harmful action of external factors.…

01 March, 2024

Every day our eyes are exposed to the harmful action of external factors. One of the main threats is excessive exposure of the eyes to harmful HEV light emitted by the screens of smartphones, televisions and other devices. The eyes, like other organs, get tired, they need training and rest, and above all they require proper nourishment, which can be supported by liposomal supplements and eye supplements.

Eye health – what the retinal receptors are

The next stage in the process of vision is the physiological process of stimulating the receptors of the retina and triggering a nerve impulse, which is transmitted to the cerebral cortex. This part of the process is the responsibility of the retinal receptors – the cones and the rods (2). At the moment of stimulation by light, their chemical structure changes momentarily and an electrical impulse arises that is conducted to the brain along nerve fibres. The rods are highly light-sensitive and are responsible mainly for detecting shape and movement. They cannot, however, distinguish colours. They receive only light with the characteristics of the colour grey, in various shades, as stronger and weaker. The cones, on the other hand, are less sensitive to light, but they are responsible for the ability to distinguish colours. They also make it possible to perceive details. The combination of the properties of both receptors creates the ability to identify objects, to orient oneself in space and to distinguish colours, and therefore the most important elements of the process of vision. Colour vision, by creating contrast between objects, allows them to be identified more quickly and more efficiently, and thereby provides the information necessary for spatial orientation.

Biological activity of the macula

The macula is a round area at the posterior pole of the retina, whose inner layer contains a yellow pigment – xanthophyll – and carotenoids – lutein and astaxanthin – in a higher concentration than in the peripheral retina (3). This is the place where the resolution of vision is the greatest, as a result of the more intense density of the cones. At the same time it is an „intensively working” area, characterised by a high metabolism of the cells. High metabolic activity favours the formation of potentially harmful free radicals, especially oxygen ones. The above processes are inseparable elements of cellular metabolism and do not constitute a threat as long as they are quickly inactivated by the antioxidant defence systems present in the cells.
The formation of potentially harmful free radicals is a process that commonly takes place in a living organism throughout its whole life – in various types of cells and tissues. Oxidative stress is defined as a disturbance of the cellular pro-oxidant and antioxidant balance in the direction of oxidation reactions, proceeding with the participation of reactive oxygen species (ROS – Reactive Oxygen Species).

For several reasons the retina is an area particularly predisposed to the formation of ROS. One of the more important factors is the high partial pressure of oxygen, which is the substrate for oxygen radicals. The retina, and especially its photoreceptors, are exceptionally hard-working cells with an intensive metabolism, which require large amounts of oxygen and nutrients. Liposomal supplements can help to neutralise these radicals and support eye health.

What is good for the eyes?
Lutein and astaxanthin are the most important

Carotenoids are pigments synthesised in plant organisms and in bacteria. So far more than 600 carotenoids have been identified, and barely 10% of them occur in the everyday diet (4). In plant and animal organisms carotenoids have a colour ranging from yellow to red. In the human body they are exclusively of dietary origin. The most common carotenoids occurring in the diet are: α- and β-carotene, β-cryptoxanthin, lutein, lycopene and astaxanthin.

In 1945 George Wald discovered that the yellow colour of the macula lutea in the eye is the work of lutein, astaxanthin and its oxygenated form – meso-zeaxanthin.
Astaxanthin and meso-zeaxanthin are dominant in the macula, while lutein is the dominant component of the peripheral part of the retina.

When comparing the individual xanthophylls present in the retina, it should be emphasised that lutein and astaxanthin are components that come from food (present in and synthesised by plants), whereas meso-zeaxanthin does not come from the diet. There is some evidence for the hypothesis that meso-zeaxanthin is formed from lutein in the retina of the eye. Meso-zeaxanthin is not found either in plasma or in the liver, while the lutein present in the macula undergoes enzymatic or photochemical conversion into meso-zeaxanthin.

Lutein and astaxanthin are fat-soluble, so liposomal supplements are the most effective form of delivering them. The distribution of the pigments and their deposition in the retina and in other tissues of the eye improves thanks to the use of liposomes as carriers of lutein. In studies carried out on an animal model, Liu et al. (5) demonstrated that the use of a lutein carrier in the form of a suspension of lipid microparticles increases the concentration of lutein not only in the retina, but also in the sclera, which with the use of traditional drug carriers (tablets) constituted a natural barrier to carotenoids.

An adequate supply of lutein and astaxanthin plays an important role in the process of maintaining the normal function of the retina. The pigments of the macula lutea – lutein, astaxanthin and meso-zeaxanthin, that is the oxygenated form of lutein – act as strong antioxidants and at the same time as filters of UV radiation. The macular pigments also influence the physical processes connected with vision: they increase contrast sensitivity and the contrast between the surroundings and the background, and they reduce reflected luminance. Eye supplements with these ingredients can significantly support eye health.

Lutein and astaxanthin are essential for the normal functioning of the organ of sight. In addition, it is worth ensuring the right level of vitamins A and E. These vitamins also play an important role in preserving the health of the eye. As with every organ, diet and supplying the eye with the necessary nutrients are extremely important for the eyes. The second important element is exercise and rest; the eyes, too, need both training and rest. You can learn simple techniques for protection against harmful HEV radiation here.. Take care of your eyes today.
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