US Department of Agriculture
Food and Nutrition Topics a to Z
More than just food and nutrition links can be found in this index of health topics. The USDA's Food and Nutrition Information Center provides access to a world of health information.
CK-12 Foundation
Ck 12: Biology: Food and Nutrients
[Free Registration/Login may be required to access all resource tools.] Discusses classes of nutrients and their functions in the human body.