A study helps answer a question many of us ask when deciding whether to buy organic food: does it really make a difference?

When Andreina Febres, a mother of two living in Oakland, California, signed up for a study evaluating whether an organic diet could make a difference in the amount of pesticides found in her body, she didn’t know what researchers would find. But her family, and the three others across the country that participated, would discover that they all had detectable levels of the pesticides being tracked. They would also discover that after only six days on an organic diet, every single person would see significant drops in those pesticides, including several linked to increased risk of autism, cancer, Parkinson’s, infertility, and other significant impacts on health.

“It’s good to see that just after a week there was a dramatic drop,” Febres said after seeing the results. “I would love to get those pesticides out of my body and my family’s bodies.”