Those who emphasize the public good emphasize the medical consensus that appropriate levels of water fluoridation are safe and effective to prevent cavities and see it as a public health intervention, replicating the benefits of naturally fluoridated water, which can free people from the misery and expense of tooth decay and toothache, with the greatest benefit accruing to those least able to help themselves. This perspective suggests it would be unethical to withhold such treatment.[61] In her book 50 Health Scares That Fizzled, Joan Callahan writes that, "For lower-income people with no insurance, fluoridated water (like enriched flour and fortified milk) looks more like a free preventative health measure that a few elitists are trying to take away."[62]