The mental health of adolescents has deteriorated significantly in the last 25 years, e.g. there is an increase in depression in adolescents. Supplementation of trace elements and vitamins as well as of essential fatty acids led to better social behavior in schoolchildren and in some cases also to an increase in IQs.
Consumption of cholesterol and saturated fat is associated with disorders of brain function. Emotional stress states improved by the renunciation of sugar.
In October 2006, a study from Norway was published, in which the influence of sugary soft drinks on the mental condition of adolescents was examined. About 5,500 young people participated in this study. It turned out that boys or girls who consumed more than four glasses of soft drinks daily suffered from contact difficulties and hyperactivity much more frequently than the other adolescents. Preservatives and food dyes have been known for quite some time suspected to play a role in the development of the hyperactive syndrome ADHD. A research team from the University of Southampton studied 153 three-year and 144 eight-year-old schoolchildren with no known food allergies or behavioral disorders from the average UK population. The children were given two different mixtures of food colors in the study. As a control, a fruit juice was used, which was not different in taste and color from the other concoctions. In the following weeks, the children were observed for their behavior. The older children also had to undergo a computer-based test to check their ability to concentrate. Children who consumed concoctions of preservatives and dyes tended to be more hyperactive than the control group. This seems to prove that artificial food additives can adversely affect the behavior of children. However, one cannot assume that the omission of additives eliminates all hyperactivity symptoms, because of course many other factors can underlie the hyperactivity syndrome.
In a study carried out in Kuwait, the result of which was published in 2006, it could be shown that the intake of food dyes in school children sometimes exceeded the ADIs (ADI = permitted daily dose) by a factor of 2 to 8.The brain of children is very sensitive to heavy metals and other environmental toxins. Even low levels of lead in the blood that used to be considered harmless can contribute to the development of ADD. This is the result of a study conducted by Michigan State University on 150 children. Children with ADD had higher whole blood lead concentrations than controls; none, however, had a concentration above 100 mg / l. This concentration was previously considered the upper harmless limit for children.
The mean lead concentration of ADD children in the MSU study was less than 13 mg / L. In this study, it was demonstrated for the first time that even very low levels of lead in the blood can be regarded as a cause for the development of ADHD in children. The lead level considered "safe" should be corrected downwards, at least to 50 mg / l. An investigation by the Federal Environment Agency of 1,790 children aged 9 to 14 has shown that the general pollution levels in children have not decreased despite numerous prohibitions and restrictions on use. Although the amount of heavy metals and ingredients used in wood preservatives is lower than it used to be, children today are increasingly coming in contact with plasticizers.
A "healthy brain" diet is also of great importance for the intelligence. According to the Brain Training Society, the influence of diet on intelligence is often underestimated. The Americans would eat too fat, too sweet and too much fast food. Much of the population today would eat much worse than before. Until the nineties of the previous century there was a steady increase in the intelligence quotient; since then, one can observe a decline in IQ in some western states.