以下訊息來自南非ＲＰ協會 維他命Ａ的警告 RP Taiwan 感謝南非 RP協會 The following informations are from RP SA Association about Vitamin A Warning, Thanks RP SA RP Taiwan
Despite various articles in Retina news and other publications the dangers of Vitamin A supplementation are still being ignored. Supplements containing high doses of Vitamin A and Beta carotene should not be taken by smokers due to an increased risk of developing lung cancer and women contemplating pregnancy, where foetal abnormalities may be the result.
In addition people with juvenile macular degenerations should not take these supplements. In patients affected by Stargardt Dystrophy and Cone rod Dystrophy caused by a mutation in the ABCA4 [ABCR] gene the mutation may retard the retina’s ability to convert the retinal form of Vitamin A back to the Retinol form. A resultant buildup of Lipofuscin clogs the retina.
Professor Jacquie Greenberg co- principal investigator of the Retinal Degeneration Project at the University of Cape Town cautions eye care practitioners not to prescribe supplements containing high doses of Vitamin A or Beta carotene to patients with juvenile forms of macular degeneration. She cites the article by Dr Robert Koenekoop in the journal of Ophthalmic Genetics. June 2003.
" Vitamin A supplementation is not recommended for ABCA4 mutation-positive patients because of a real danger that vitamin A accumulation is the guilty party in this disease. In addition, careful protection against the sun is strongly recommended. "
More recent research would seem to collaborate this and Retina South Africa urges all their Juvenile MD members to avoid supplements that contain high doses of Vitamin A and beta carotene. We further advise all our members, irrespective of the type of degeneration, to wear sunglasses with good UVa and UVb screening properties.