When thinking of eye health, foods rich in beta carotene and vitamin A, like carrots, may come to mind as they are linked to good eye health; however, there is evidence of a link between vitamin D and eye health as well. Vitamin D is a very popular vitamin mostly known for its benefits in bone and teeth health.
Although vitamin D is a well-known vitamin, some may not understand exactly what it is. Before getting into the relationship between vitamin D and eye health, it’s first important to understand what vitamin D is, and its sources.
WHAT IS VITAMIN D AND WHAT ARE ITS SOURCES
Vitamin D is a fat-soluble vitamin that is obtained from three sources: food, the sun, and supplements. It is present in a limited number of foods such as salmon, eggs, and raw milk. Once it is in the body, the body can turn it into a hormone. Vitamin D aids the body in using calcium and phosphorus to create strong bones and teeth.
Vitamin D is also the only vitamin formed with the help of direct sunlight. According to the American Optometric Association, the ultraviolet B rays from the sun are absorbed by the skin and triggers the synthesis of vitamin D. Vitamin D is then stored in the liver, and provides many benefits to the body.
AGE-RELATED MACULAR DEGENERATION AND VITAMIN D
There has been recent evidence that vitamin D plays a role in protecting against age related macular degeneration (AMD). AMD is a degenerative eye disease that is a leading cause of vision loss in older adults. According to Medical News Today, AMD affects approximately 9 percent of Americans aged 40 years and older. Specifically, the disease results in degeneration of the macula, which is the central part of the retina. The retina is how one focuses and has precise vision.
There are various genetic factors that affect the chances of a person developing AMD such as age, race, and gender. Even given the genetic factors, research has shown that vitamin D may still be a factor in eye health. Vitamin D has anti-inflammatory properties, and it is believed that inflammation is a factor in the development of AMD according to University of Buffalo research. Also, vitamin D has antiangiogenic properties, which means it helps prevent the formation of new blood vessels. New blood vessels are often seen in the later stages of AMD. These new blood vessels grow behind the retina and then leak blood and fluid into the eye, which causes vision problems.
University of Buffalo researchers concluded, based on their analysis, that having good levels of vitamin D is good for overall health; however, when it comes to eye health the focus is on vitamin D deficiency and the negative impact this deficiency has on eye health.
DRY EYE AND VITAMIN D
The International Journal of Rheumatic Diseases published a study back in 2015 that suggest vitamin D deficiency plays a role in reducing the risk of dry eye. The American Optometric Association defines dry eye as a condition in which a person does not produce enough quality tears. This is an issue because if a person does not produce enough quality tears eyes cannot be properly lubricated and nourished.
As with AMD, dry eye is a common eye condition that is more prevalent in older adults. Most people over the age of 65 will experience some form of dry eye with symptoms ranging from stinging and redness to light sensitivity.
Because vitamin D has anti-inflammatory qualities, the researchers in this study believe that vitamin D deficiency plays a role in dry eyes. The research study concluded that “that vitamin D plays a protective role in the development of dry eye, probably by enhancing tear film parameters and reducing ocular surface inflammation…Vitamin D supplementation may be useful for dry eye symptoms, including ocular discomfort, soreness, redness, ocular fatigue, sensitivity to light and blurred vision.”
DAILY RECOMMENDED AMOUNT OF VITAMIN D
The daily recommended amount of vitamin D for adult only varies slightly. The National Institutes of Healthrecommends 600 IU (international units) per day for adults 18 – 70 years old. The recommended amount for adults 71 and older is 800 IU. As noted in the University of Buffalo research, the focus is maintaining a good level of vitamin D to avoid vitamin D deficiency. Vitamin deficiency is what has a negative impact on eye health.
Symptoms of Vitamin D Deficiency
If one is concerned about the link between eye health and vitamin D, it makes sense to want to understand the symptoms of vitamin D deficiency. Some symptoms include bone and muscle aches and pains, severe fatigue, and even depression. While this information is focused on eye health, there are other health issues that are affected by a vitamin D deficiency. It is always best to consult with a health care professional when warranted.
Vitamin D is a versatile vitamin known for its benefits in bone and teeth health, and other health issues. There has been some promising research on the link between vitamin D and eye health. Vitamin D’s anti-inflammatory properties have shown to have a positive impact on two of the most common eye health issues, AMD, and dry eye. Research concludes that people should maintain a healthy level of vitamin D, and do not recommend additional vitamin D to support eye health. The most important note is to avoid vitamin D deficiency.