Want to watch better-quality PBS Video? Sign in to access HD streaming!
Roger A. Sunde, Professor, Department of Nutritional Sciences, UW-Madison, explains that copper and zinc, essential elements, were discovered in food while using the bioassay approach (feeding studies with rats) while searching for vitamins. Both vitamins and trace essential minerals were present in levels so low as to evade detection by analytical means, and had to be teased out using bioassay.
Upgrade Your Viewing Experience
This video is available to CallSign viewers with a Passport account. Passport gives you access to a wealth of premium content not previously available online, including full seasons of your favorite shows.