In truth, the vast majority of older dishes were made using heavy metals of one sort or another. And with red glazed dinnerware, uranium oxide gets a turn under the microscope as a possible concern rather than lead. Until bomb-making research took away uranium from dish manufacturers during World War II, most all dinnerware glazes were made using uranium oxide. The red glazes contained more, which made them more expensive to purchase back in the day, but even light colored dishes produced prior to 1943 contained uranium oxide in the glaze. Then after 1959, uranium oxide was once again used to produce the attractive, colorful glazes collectors admire.
What do the researcher's say about safety? According to information published on the Oak Ridge Associated Universities Web site, "it is likely that the major health issue associated with this dinnerware is not the radiation exposures but the ingestion of uranium or other metals that have leached into food or drink in contact with the dinnerware. One FDA study measured 1.66 x 10-5 uCi/ml in a 4% acetic acid solution in contact with the ceramic dinnerware for 50 hours - this exceeded the ICRPâs maximum permissible concentration (MPC)."
So are these dishes safe for home use? There's a possibility that under the right conditions with continual use that a person using glazed ceramic dinnerware could ingest unacceptable amounts of uranium. But how often do you eat acidic foods that have been in contact with a plate for 50 hours? Most collectors groups dealing with vintage dinnerware don't buy into the notion that these dishes, red or otherwise, are unsafe. If you're personally concerned, finding an alternate method for food storage would likely be the answer given the research at hand.
Would I personally eat off older glazed dinnerware containing uranium oxide in the glaze? Yes, and I'd enjoy every bite! But each person has to proceed within his or her own comfort zone. If you don't feel safe serving food on older glazed dinnerware based on your own personal knowledge and research, perhaps you can just enjoy displaying it in your china cabinet as an alternative.