Energy hunger of child brains slows growth

Energy hunger of child brains slows growth

08/26/2014

Humans grow relatively slowly compared to monkeys or other mammals. This has to do with the fact that the brain of Homo Sapiens consumes a lot of energy. US researchers have now fed this long-held assumption with data.

Energy demand of the brain with four to five years highest
In relation to monkeys or other mammals, humans grow relatively slowly because their brain needs a lot of energy. American researchers have now fed this long-held assumption with data. According to a news agency dpa news agency, Christopher W. Kuzawa's team at Northwestern University in Evanston, Illinois, found that brain energy demand is highest when body weight growth is the lowest, at four to five years.

Young people's growth is similar to that of reptiles
The brain needs in this phase about 43 percent of the energy of the entire body, write the scientists in the journal „Proceedings of the National Academy of Sciences“. This is more than twice the energy requirement of the adult brain. The researchers also write that the slow growth of young people is more like that of reptiles than of mammals. „As humans we have much to learn, and this learning needs a complex and energy-hungry brain“, said Kuzawa in a press release from his university. „At a certain age, it becomes difficult to estimate the age of small children by their size. Instead, one must hear what they say and observe their behavior.“ The reason for this is that body growth almost comes to a standstill when the brain consumes significant amounts of energy from food.

Energy needs of the brain half year after birth at a low
It is noticeable that the energy requirement is not greatest when the brain has the largest volume compared to the body - this would be the case immediately after birth. Only about half a year after birth, the energy requirement of the young brain sinks to a low. At the age of four, it reaches the highest energy demand in relation to the body and at five years the highest energy consumption ever. The energy consumption of the brain is inversely proportional to the weight gain of boys in the age range between half a year and 13 years. According to the researchers, this relationship ends in girls at the age of about eleven, as puberty sets in earlier.

Energy demand determined earlier via oxygen consumption
As the researchers write, the energy needs of the brain had been determined in previous studies on the basis of oxygen consumption. The team around Kuzawa, however, chose a different path and first compared the energy requirement in the form of glucose (simple sugar) with the growth of body weight. In a previous study, glucose consumption using positron emission tomography (PET) was measured in 36 individuals, from infants to adults. The data for the development of the brain volume in turn come from a study by magnetic resonance imaging with 402 people in this age range. The team also resorted to available material for further data.

Energy demand of the child brain was underestimated
For example, up to 30 percent of the glucose consumed would not be used to generate energy, such as at five-year-olds, but would be needed for the production of proteins associated with the formation of synapses between nerve cells. The scientists write that the energy requirement of the children's brain has therefore been underestimated so far. „Our brain is a true energy monster in childhood“, Sun Kuzawa in a message. According to experts, it is important, especially in childhood, to provide enough brain food with the help of a healthy diet. Among other things, complex, long-chain carbohydrates, which are present in wholegrain bread or oatmeal, are recommended. Wholegrain muesli with fresh fruit are a good start to the day, not only for children. (Ad)