Actually UVB may be a vital consideration in maintaining the good health of certain species of frogs and toads. I have learned during my time as an amphibian keeper at the Omaha Zoo that many species of amphibians require UVB basking areas. I use a 50 watt UVB bulb for my frogs and toads and they are thriving especially my fire-belly toads. Here are the links to a couple of articles that I highly recommend:
www.amphibianark.org/pdf/Husbandry/Amphibian%20diet%20nutrition.pdf
www.amphibianark.org/pdf/Husbandry/Amphibian%20UV-B%20and%20Vitamin%20D3.pdf