Very old but mentally fit: The importance of phytochemicals in preventing neurodegenerative disorders

Abstract

According to estimates, the number of people with dementias will treble, from 35 million today to about 115 million in 2050. Consequently, there is great interest in preventive measures for age-related neurodegeneration. Some prospective studies have shown a positive association between a balanced diet and cognitive functioning. Phytochemicals are being considered as a potential contributor in this. Because of their antioxidant effect in plants, it has been assumed that they may prevent oxidative stress in humans, too. For a long time, oxidative stress has been suggested to be one possible cause of the loss of cognitive performance in old age. However, this theory has been questioned by many in the meantime. Today, the favoured theory is the hormesis theory, which proposes that phytochemicals act as stressors in the human organism and thus induce health-promoting effects. In vitro, they trigger the activation of the body's antioxidant defense, increase cellular repair mechanisms and support the immune defense system. However, a scientific basis for the recommendation of intake of phytochemcials with the aim of preventing age-related neurodegenerative changes is currently lacking. © Georg Thieme Verlag KG Stuttgart · New York.