Nutrition

This is primarily a source for raw data, in the form of nutrition information from most commercially available foods. There are also specific databases for things like flouride, choline, flavonoids etc...

More raw data, this time about dietary supplements and multivitamins/minerals (MVMs).

An amazing source for data on nutrition issues like cholesterol, diabetes and obesity.

This interactive map will help you find information on how "[f]ood environment factors—such as store/restaurant proximity, food prices, food and nutrition assistance programs, and community characteristics—interact to influence food choices and diet quality." You can also "[c]reate maps showing the variation in a single indicator across the U.S.; for example, variation in the prevalence of obesity or access to grocery stores across U.S. counties."

An excellent source for review articles and introductions to dietary supplements. You can find information on their history, clinical trials, how they work etc...

This is the main government sponsored nutrition site. It is a great source for general information on topics like dietary guidelines, weight management and healthy living. it's a good starting place, but you'll have to look elsewhere for more scientific analysis.

This site has more of a focus on health topics than nutrition, but it's a good place to get more scientific sources than you would find on nutrition.gov

Information on the government's national School Lunch Program

This is a series of links that Penn State has put together to help you find nutrition information on mothers, infants, children, adolescents, and mature adults.