New research has called into question the commonly held notion that free radicals increase the effects of aging on the body. Free radicals are oxygen molecules that are often blamed for the physical effects of aging on the body's cells and DNA. As a result, nutritionists have advised consumers to increase their intake of anti-oxidant fruits and vegetables such as spinach and broccoli to reduce the numbers of harmful free radicals in their bodies. A large diet and supplements industry has also grown around the need to reduce the excess oxygen molecules.