In order to be your best it is essential to protect your brain from injury. Wear your seatbelt when you're in a car, and wear a helmet when you ride a bicycle, motorcycle, or go snowboarding. Make sure children wear helmets. One head injury can ruin a life. Along the same lines, do not let children hit soccer balls with their heads.
Soccer balls are heavy.
Repeatedly slamming a child's head against a soccer ball may cause minor repetitive trauma to the brain. At this time there are not enough studies to say heading soccer balls is safe. I encourage my children to play golf, baseball, and tennis, rather than football, soccer, or hockey. Current brain imaging research has shown that many chemicals are toxic to brain function. Alcohol, drugs of abuse, nicotine, much caffeine, and many medications decrease blood flow to the brain.