Gabe was reading an article in a body-building magazine that said a particular world-champion body builder regularly eats a dozen raw egg whites per day. From his recent nutrition studies, Gabe surmised that the body builder is at risk for developing a deficiency of because a protein in raw egg whites binds this vitamin and inhibits its absorption

Biotin

Explanation:

Based on the scenario being described within the question it can be said that the type of vitamin that is being mentioned would be Biotin. This vitamin plays a really important role in the health of your hair, skin, and nails. Since this vitamin is completely water soluble, the egg whites bind to this vitamin and inhibits its absorption meaning that the vitamin's effects are neutralized and it will not provide it's benefits.