Vitamin A supplementation in conjunction with eating fish high in fatty acids can delay vision loss in patients with retinitis pigmentosa, according to a new study.
Researchers led by Eliot Berson, MD, of the Massachusetts Eye and Ear Infirmary in Boston conducted three studies following patients with RP. They found that the patients who ate one to two three-ounce servings of oily fish per week and took 15,000 IU of vitamin A each day had slower rates of distance and retinal acuity loss.
"It is well known that if the retina does not have sufficient vitamin A, it will die,” Berson told Medscape Medical News.
“Patients are advised to take vitamin A to replace their rods and to eat oily fish to enhance delivery of vitamin A to cones."
The three major trials, which lasted between four and six years, involved 357 patients with RP from the ages of 18 to 60. All the patients were administered daily doses of oral vitamin A palmitate. 142 individuals were in a group with a diet low in omega-3 fatty acids (less than 0.2 grams per day), while the other group consisted of 215 individuals with a high fatty acids intake (0.2 grams per day or more).
Those in the high-intake group were able to delay loss of distance acuity, measured by a test that required study participants to identify numbers on a chart.
"Since vitamin A plus an omega-3-rich diet slowed the rate of decline of distance and retinal acuity by about the same extent, we conclude that the benefit of this combination was due to an effect on preserving central retinal function," the study authors wrote.
RP is a group of genetic eye conditions that affects about one in 4,000 people.
The study was published online Feb. 13 in Archives of Ophthalmology.
