An insult or injury at one stage of development may have a long-term effect. For example, introduction of a hormone into the fetal brain at a critical time can permanently influence the structure and functional capacity of the brain. Nutrition scientists believe that nutrition can have a programming effect. Several pieces of evidence support the idea.
Extensive evidence supports the phenomenon of nutritional programming in animals.
Epidemiological evidence for humans also supports the concept. To date 15 intervention trials with humans have been conducted which also support the idea. The intervention trials were not planned and conducted deliberately. To do so would have been unethical. They occurred by accident in the United Kingdom when physicians in the hospitals fed preterm infants on formulas that were available at the time.