Nutrition is vital to human growth, development, and life maintenance and, as such, is also important to oral health. Dietary nutrients include carbohydrates, proteins, fats, vitamins, minerals, and water. This article reviews these nutrients, their functions and sources, and how they relate to oral health and disease. Concepts about which the oral health care provider must be aware in order to counsel patients regarding the impact of diet on oral health and toward healthy lifestyle choices are discussed.