"There's definitely a stigma," said Gibson-Staneland. "Cleanliness is next to godliness, so you don't want to be known as someone who puts dirt in their mouth."
And there may be medical problems associated with over-consumption of clay. Constipation is a common complaint among those who eat clay regularly, due to the same binding effect that makes it an effective anti-diarrhea remedy.
"It will make you constipated," Joiner admits.
For women who are concerned about vitamin and mineral deficiencies during pregnancy, Katz offers this advice: "Take a prenatal vitamin."
But those who have been eating clay all their lives are unlikely to stop, and now some experts are unlikely to encourage them to give up the habit.
Salt, notes Gibson-Staneland, is also a mineral, one that is found on almost every restaurant table in America.
"If most humans readily use water and salt," asks Gibson-Staneland, "why not utilize clay as a food source if it is beneficial?"