In the US, about 20 million people live with some degree of age-related macular degeneration, which is the leading cause of vision loss in individuals 60 and older. The macula is an oval-shaped spot of pigmentation on the retina, and the degeneration of this part of the eye results in a loss of sharp vision. Individuals with macular degeneration may lose the ability to recognize faces, read, and perceive colours.
Although macular degeneration is currently irreversible, it is possible to prevent it through lifestyle changes. One perhaps-obvious way to reduce one’s risk of the disease is to protect the eyes from sun exposure through hats and sunglasses. The sun’s rays can damage your eyes along with your skin, so it is best to avoid excessive exposure.
Getting regular exercise, maintaining a healthy weight, and avoiding smoking are other ways to reduce one’s risk of developing the disease. Yet what does the scientific literature say about foods that might help to lower the risk of getting macular degeneration? The rest of this post will explore a few articles.
There are very few diseases that cannot be prevented, cured or slowed by a healthy diet, and age-related macular degeneration (AMD) is no different. An NIH study from 2010 demonstrated that overall diet quality was related to a person’s risk of developing AMD. In the study, a healthy diet was defined as one with more servings of fruits, vegetables, soy, and nuts, and with less or no servings of meat and processed food. Individuals in the highest quartile of diet quality had a 54% lower probability of developing AMD compared to the other participants in the study.
How, specifically, might diet affect the risk of AMD?
There is a part of the eye called the retinal pigment epithelium, which is a layer of cells just outside the sensory part of the retina that nourishes and protects the machinery of the eye. The retinal pigment epithelium takes up yellow plant pigments from our diet.
You’ve probably heard that carrots are good for the eyes, and that is certainly true. Carrots are a good source of beta-carotene, which is converted to vitamin A in the body and can prevent the formation of both cataracts and macular degeneration. Carrots also contain lutein, which is an antioxidant that increases the density of the retinal pigment epithelium, increasing this layer of cells’ ability to protect your eyes.
Dark green vegetables like spinach and orange and yellow fruits and vegetables also contain a pigment called zeaxanthin. This is another compound that is associated with a lower risk of AMD.
Anthocyanins are another class of pigments usually found in purple or blue plants like red cabbage or blueberries. In a laboratory experiment using cultures of retinal pigment cells, the anthocyanins from blueberries protected the cells from light-induced damage.
Goji berries are known as a superfood, and their effect on retinal pigmentation is indeed substantial. A double-blind randomized placebo trial revealed that eating just 15 goji berries a day protected individuals from loss of pigment from the retinal pigment epithelium, and also increased plasma zeaxanthin level and antioxidant capacity.
As a closing note, eggs also contain zeaxanthin in their yokes. Yet goji berries contain 60 times that amount per serving, and do not contain high amounts of saturated fat and cholesterol that put an individual at greater risk of many chronic diseases. Thus, plants such as goji berries, spinach, carrots, and peppers are the healthier choice for consuming the pigments that protect our eyes from damage.
AMD is not an inevitable condition that we are helpless to protect ourselves from. As we have seen, there are dietary changes that we can take to lower our risk of developing the disease.