The omega-3 fatty acid known as DHA is touted for its many health benefits, and vision protection may be one of them. A new study published in Investigative Ophthalmology & Visual Science found that DHA, one of three forms of omega-3 fatty acids and the substance that makes up about 30% of brain matter, prevented age-related vision loss in lab mice. DHA is considered the most complex form of omega-3, but is among the most difficult to consume in sufficient amounts because it is contained in so few food sources.
Dr. Ann Bajart, a corneal specialist and clinical instructor in ophthalmology at Harvard Medical School, says the vision study likely applies to humans.
How it works
Researchers found that mice fed a diet supplemented with DHA did not experience a buildup of the toxic molecule A2E at the back of the eye. Over time, A2E normally accumulates in the retinal pigment epithelial cells and leads to vision loss. "DHA is the primary structural fatty acid of the gray matter of the brain and the retina," explains Dr. Bajart. "So it makes sense that a DHA supplement, or diet rich in DHA, may help slow the degeneration of the retina, including macular degeneration, the most common form of blindness in older people."
DHA is found in coldwater fish, such as salmon, cod, and tuna. Most studies find that eating foods rich in DHA also correlates with lower rates of heart disease, cognitive decline, and arthritis.
Benefits and dosages
Dr. Bajart says that while DHA will not reverse retinal damage, it may help preserve vision, and relieve dry eye and chronic inflammation of the eyelids.
To help protect your vision, we recommend getting DHA from food—fish or flaxseed, including flaxseed oil. The American Heart Association recommends at least two servings of fish per week. Women who are pregnant or who are of child-bearing age and might be pregnant should generally avoid fish that are most likely to contain some mercury: tilefish, swordfish, shark, mackerel, and tuna. If you want to take fish oil supplements, recommendations for heart health suggest taking 3,000 milligrams per day.
