Toothpaste. That recommendation is primarily for children to make sure that they don't over consume fluoride as teeth are forming. If you have a child, discuss appropriate toothpaste portion with child's Dentist or Pedodontist. As an adult, you would have to swallow a bathtub full every day to even begin to see a problem.
Ingredients. Toothpaste is not formulated to be ingested. It is designed to be used in the mouth, and then spit out. Ingestion of those ingredients can upset your stomach.