The bacterium added to the yogurt was Lactobacillus reuteri—in a form particularly resistant to digestion. Within six weeks, their levels of bad LDL cholesterol sank by 8.91 percent. That’s about half the improvement attained by taking a mild anti-cholesterol drug—but without the side effects. Studies using other types of bacteria lowered cholesterol levels by as much as 11 to 30 percent.