A greater variety of foods, advances in food production and technology, changing consumer preferences, and revised Federal standards for enrichment are affecting the type and amounts of nutrients available in the U.S. food supply. Americans have available to them more carbohydrates, protein, and fat-and this means more calories. Sources of fat are shifting from animal products to plant sources. Levels of most vitamins in the food supply increased-especially thiamin, niacin, folate, and vitamin E (although two vitamins, A and B12, had lower levels)-from 1970 to 1990. The amount of most minerals also rose, especially calcium, phosphorus, magnesium, iron, and potassium. For most individuals, the nutrient levels present in the food supply are adequate in preventing deficiency diseases. These findings are taken from the most recent estimates of nutrients available from the U.S. food supply. Changes in foods and nutrients are monitored with disappearance data and reported on a per capita basis (see box for more details). These data measure U.S. supplies available for human consumptionnot what Americans actually eat. Nonetheless, food and nutrient per capita values are useful for tracking the relative magnitude of changes in the American diet over time.