Vitamin D Newsletter
Should I Supplement With Vitamin A?
John from California writes:
Are you saying no vitamin A at all or just not too much of a good thing?
Dr. Cannell replies:
No extra vitamin A unless you have a bowel disease that impairs absorption of vegetables and transportation of carotenoids. The paper referenced at the end of this paragraph discusses how Americans are getting too much of a good thing. Vitamin A is like vitamin D, it has a U-shaped curve, too much or too little will harm you. Too much is the rule, not too little, in developed countries. Furthermore, it gives a mechanism by which excessive doses of vitamin A will impair brain development and, although I can't put my finger on the reference right now, at least one author has proposed that excessive vitamin A intake may worsen autism. The vitamin D theory of autism would predict just that.
Page last edited: 16 June 2011