In this article I will talk about the scientifically proven benefits of certain nutrients for the health of our eyes. I limit myself here to vitamins, minerals and fatty acids that occur in our daily diet.
The best examined nutrients related to vision are docosahexaenoic acid (DHA) and the carotenoids beta-carotene, zeaxanthin and lutein. Vitamins E and B2 and minerals selenium and zinc are most likely to provide benefits for the eyes as well.
Docosahexaenoic acid (DHA) belongs to the omega-3 family. Not only does it help to maintain normal vision in adults, its use by pregnant and lactating women is critical for the vision development of the foetus and infant while breastfeeding. DHA is found almost exclusively in fish and seafood. Oily fish such as mackerel, salmon, eel, herring and sardines are an important source of this acid. These fish accumulate omega-3 acids in their adipose tissue. Nowadays you can purchase 100% vegan DHA supplements made from algae.
In the human body, carotenoid beta-carotene from foods is converted into vitamin A. Vitamin A helps maintain the health of mucous membranes, skin and eyes. Beta-carotene is found in orange and yellow fruits and vegetables, such as: carrots, pumpkins, yellow apples, apricots, peaches and gala melons.
Zeaxanthin is also a carotenoid. It is actually one of the most abundant carotenoids in nature. Zeaxanthin gives certain plants their characteristic orange and yellow color. The name comes from Zea Mays (a variety of common corn in which zeaxanthin provides the yellow base pigment) and Hanthos, the Greek word for “yellow”. Zeaxanthin is an important component of the pigment in the human retina. A small amount of zeaxanthin is also found in the human brain. Zeaxanthin plays an important role in the functioning of the eye, as it is responsible for central visual acuity (the clarity with which objects distinguish themselves from their surroundings). Important food sources of zeoxanthin are corn, yellow and orange peppers, dried peppers, saffron, all kinds of pumpkins, zucchini, kiwi, grapes, orange juice and goji berries.
Another carotenoid found in significant amounts in the retina of the human eye is lutein. Scientists have long suspected that lutein is essential for vision. A study in China, involving 120 night drivers, concluded that regular consumption of lutein improves night and low-light vision.
Good sources of lutein are egg yolk, corn, spinach, red grapes, cucumber, celery and green peppers.
It is most likely that lutein and zeoxanthin act synergistically, that is, they provide greater health benefits when consumed together rather than separately.
Laboratory studies, animal studies and epidemiological studies show that specific bioactive substances can have a prophylactic effect on the macula of the eye. The macula is the part of the retina with a diameter of a few millimetres that is responsible for visual acuity. For example, we need a healthy macula to be able to read, drive, view details of objects, and more. Age-related macular degeneration (AMD) is a dystrophy that occurs in the center of the macula. Scientists have pointed out that regular intake of vitamin E is necessary for a healthy macula. For example, a large-scale study of age-related visual pathology Pola (started in 1999, ongoing) shows that the risk of AMD is reduced by as much as 82% in people with high blood vitamin E levels compared to people with low levels of this vitamin.
The best natural sources of vitamin E are various vegetable oils, nuts, seeds, grains, fruits and vegetables, avocados and berries.
Vitamin B2, also known as riboflavin, is also necessary for healthy eyes. This vitamin protects the enzyme glutathione, an important antioxidant in the eye. A diet high in riboflavin can reduce the risk of developing cataracts (i.e. partial or complete clouding of the lens of the eye). Cataracts are dangerous because they can lead to severe and even complete loss of vision. Good sources of vitamin B2 are sour milk products, mushrooms, spinach and corn grits.
Scientists have noticed that a deficiency of the mineral selenium in the diet can lead to cataracts. The exact mechanisms are unknown, but in regions with low soil selenium levels, this disease is more common than in regions with higher levels. Brazil nuts are the richest food source of selenium on Earth. The World Health Organization (WHO) recommends consuming 55-70 mcg of dietary selenium daily. So that you know: just one Brazil nut contains about 100 mcg of selenium!
The mineral zinc is also important for the eyes. Zinc ensures that vitamin A is transported from the liver to the retina to make melanin. Melanin is a protective pigment against UV. Zinc intake also prevents poor night vision.
The following plant foods are rich in zinc: whole grains, legumes and soy products (especially tofu), peas, peanuts, nuts, seeds (especially sunflower), oatmeal and broccoli.