Heavy use of antibiotics by livestock producers is largely unregulated by the government, and roughly 80 percent of the antibiotics used in America are given not to sick people, but to healthy animals, reports the nonpartisan Government Accountability Office. This antibiotic use could eventually have a "dangerous" impact on human health. Here's what you should know:

Why do animals take antibiotics?
Even when they're healthy, many American animals being raised for food are routinely fed antibiotics to ward off illness and promote growth.

And that's unsafe?
When livestock are fed a steady diet of antibiotics, "bacteria in the guts of those animals can become resistant," says Bill Tomson in The Wall Street Journal. "Humans are then at risk of consuming that mutated bacteria, often by eating contaminated meat directly." Antibiotic-resistant bacteria, or "superbugs," can also make the jump from infecting animals to infecting humans, as happened with the H5N1 bird flu virus.

Is the government addressing this problem?
No. In the entire federal government, there is no program that addresses the heavy use of antibiotics in agriculture, "except for one $70,400 USDA project," according to the GAO report. The FDA once proposed a voluntary program to reduce antibiotic use by farmers, but that proposal went nowhere. The GAO report also notes that no agency collects data on what animals are given which antibiotics or for what reason.

What does the agriculture industry have to say about this issue?
Big Pork has spoken out against the GAO report: The National Pork Producers Council claims there is "no scientific study linking antibiotic use in food animals to antibiotic resistance in humans." But the GAO report and other researchers have found a wealth of "peer-reviewed research demonstrating the link between antibiotic overuse in animals and resistant infections in people," says Tom Laskawy at Grist.

Sources: Bloomberg BusinessWeek, Food Safety News, Grist, Wall Street Journal