Should you take extra Vitamin A if you have Stargardt’s Disease? Vitamin A supplementation is frequently recommended for certain eye diseases (AMD and Retinitis Pigmentosa, for example). This nutrient is crucial for rebuilding photoreceptors cells and proper retinal functioning. However, a study on mice published in “Investigative Ophthalmology and Visual Science” indicated that Stargardt’s Disease patients may be damaged by taking Vitamin A.
Stargardt’s Disease is a genetic form of macular degeneration. It is a recessive genetic disorder that requires the defective gene from both parents to manifest. Young people with the disorder begin to lose their central vision. By age 50, approximately 50% of patients in clinical trials were legally blind.
Patients with Stargardt’s Disease develop fatty deposits in the retinal pigment layer behind the macula. These deposits deprive parts of the eye of proper nourishment, eventually causing wasting and severely damaging vision. This disease is similar to dry age-related macular degeneration, except that is manifests in youth and has a clear genetic cause.
Vitamin A is usually recommended for eye health. It supports night vision and color vision. Vitamin A nourishes the surface of the eye to help protect the cornea, and supports the production of tears.
However, a study on mice with Stargardt’s Disease and recessive rod-cone dystrophy found that the retina was unable to break down Vitamin A, and that excessive intake may cause toxicity in these patients. Vitamin A is fat-soluble, so it can accumulate in the body and cause harm. Symptoms of excessive Vitamin A intake (acute or chronic), in typical individuals, can include blurred vision, liver damage, headaches, yellow discoloration of the skin, cracking at the corners of the mouth, and much more.
The study indicates that large amounts of Vitamin A may be contraindicated in patients with Stargardt’s Disease. In general, Stargardt’s Disease patients should avoid foods that are naturally high in carotenoids. The exceptions are foods high in the carotenoids lutein, zeaxanthin and astaxanthin, as these are not converted to Vitamin A in the body.
Using common sense and reviewing all supplementation with your doctor are the best ways to prevent health problems. At Natural Eye Care, we offer a carefully-developed eye formula designed for Stargardt’s Disease patients that does not have added Vitamin A or beta-carotine. See our recommendations for vision support for patients with this condition.
Ref: Investigative Ophthalmology and Visual Science; “Accelerated Accumulation of Lipofuscin Pigments in the RPE of a Mouse Model for ABCA4-Mediated Retinal Dystrophies Following Vitamin A Supplementation”; Roxana Radu et al; September 2008
Vitamin A Structure Research
Researchers are working on the structure of vitamin A itself in an attempt reduce patients’ chances of losing their vision to AMD, which has implications for patients with Stargardt’s who must avoid vitamin A.
According to Columbia University Medical Center researchers, if it is possible to reduce the vitamin A’s tendency to clump within the eye, scientists might be able to discourage such vision loss.
As part of the natural biological processes in the eye, vitamin A transforms chemically. Molecules of vitamin A sometimes bond to other vitamin A molecules and create clumps or deposits called “dimers.” In elderly patients with AMD high levels of vitamin A dimers are found, and they are also found in young children who develop the juvenile form of macular degeneration, Stargardt’s disease.
These animals studies are the first of their kind to produce positive results without causing vision loss and significant side effects. Source: Journal of Biological Chemistry (Mar 11, 2011).