After a google search on the "effect of ultraviolet light on vitamin A", I am somewhat convinced that prolonged exposure to sunlight depletes the vitamin content content of the foods we eat.

I wonder if the same applies to the foodstuff we buy from the markets (tomatoes, vegetables, onions, carrots, etc) that have been under the sun for so long before we take them home.

I like eating carrots because it has a high vitamin A content, most times I buy the ones that are carried about on a wheelbarrow. Since the carrots have been under the sun for a while (i don't really know how long), am I getting enough vitamin A from the carrots or am I just eating chaff?