An important part of the eye is the retina, the visual tissue at the back of the eyeball. The macula, or yellow spot, is a small area of the retina that plays a key role; its name comes from the Latin words “macula” (spot) and “luta” (yellow) because this area contains carotenoids, light-sensitive pigments.
The retina, like the film in a camera, contains many receptors and transmits information to the brain through the optic nerve. This nerve contains up to 1.7 million nerve fibers that carry an enormous amount of information. The retina contains different types of cells, such as rods and cones, that are responsible for different aspects of vision.
The rods help you see in the dark and are responsible for peripheral vision, while the cones work in the light and provide central vision, especially the perception of fine details. The retina is made up of 10 different layers where different processes take place, making it a highly organized tissue.
The role of DHA (omega-3) in eye health
The most important nutrient for the retina is docosahexaenoic acid (DHA), an omega-3 fatty acid. It is important for keeping the retina healthy and functioning properly.
DHA, or docosahexaenoic acid, is an omega-3 fatty acid found in the membranes of almost all cells. Its many functions include maintaining the fluidity of cell membranes, as well as having anti-inflammatory properties in cell membranes (1-5% of total content). However, it is important to note that DHA accounts for 50-60% of the total in the retina.
DHA plays a key role in the regeneration of certain pigments in the eye that are essential for converting light information into nerve signals that are transmitted to the brain. The primary purpose of DHA is to help the retina respond to light while providing protection against molecular degeneration.
DHA’s anti-inflammatory properties, which also block abnormal angiogenesis (the formation of new blood vessels), are an added bonus for vision. It is important to note that DHA is subject to degradation when exposed to blue light, ultraviolet light, and the omega-6 fatty acids found in vegetable oils. In fact, competition between omega-3s (including DHA) and omega-6s can affect their effectiveness.
So DHA is an important nutrient, especially for eye health, but carotenoids like lutein and zeaxanthin are also important, especially in the macula, to protect against UV and blue light.
Which foods are the best sources of these important nutrients?
The best source of omega-3 fatty acids is cold-water fish.
Here are the main sources of omega-3 fatty acids:
- tuna, especially bluefin tuna,
- salmon,
- herring,
- cod liver,
- fish oil,
- oysters,
- sardines,
- shrimp,
- grass-fed beef,
- walnuts,
- chia seeds, flax seeds,
- pastured organic eggs.
Carotenoids, including lutein and zeaxanthin, can be found in:
- dark leafy greens and salads,
- egg yolks,
- grass-fed beef.
It is important to note that these foods not only support eye health, but also have anti-inflammatory properties. However, you should avoid excess omega-6 fatty acids and reduce sugar intake to prevent free radical damage to the eyes.