Girls aged nine to 15 years old who eat peanut butter twice a week could significantly reduce their risk of breast cancer.
Researchers found that young women who ate peanut butter or nuts twice each week were 39 per cent less likely to develop benign breast diseases – some of which can increase the risk of breast cancer in later life - than those who never ate them.
The study's findings also suggest that beans, lentils, soybeans and corn also may help prevent benign breast disease.
Researchers at Washington University School of Medicine in St. Louis and Harvard Medical School studied 9,039 U.S. girls between 1996 and 2001, and then again between 2005 and 2010 when they were 18 to 30-years-old.
About 80 per cent of all breast lumps are benign, or non-cancerous, and they are considered to be benign breast diseases. These lumps tend to be moveable and smooth and are often found in both breasts.
They can be caused by benign breast changes, breast infections or injury and medications such as birth control pills and hormone replacement therapy.
"These findings suggest that peanut butter could help reduce the risk of breast cancer in women," said senior author Dr Graham Colditz, associate director for cancer prevention and control at Siteman Cancer Centre at Barnes-Jewish Hospital and Washington University School of Medicine.