Hochbetagt und klar im Kopf

 

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Zusammenfassung

Schätzungen zufolge wird sich die Zahl der Demenzkranken von heute weltweit 35 Millionen auf 115 Millionen im Jahr 2050 verdreifachen. Daher besteht großes Interesse an präventiven Maßnahmen der altersbedingten Neurodegeneration. In einigen prospektiven Studien konnte ein positiver Zusammenhang zwischen einer ausgewogenen Ernährung und der kognitiven Leistungsfähigkeit gezeigt werden. Als möglicherweise verantwortliche Inhaltsstoffe werden sekundäre Pflanzenstoffe diskutiert. Da sie in Pflanzen antioxidativ wirken, wurde angenommen, dass sie auch im menschlichen Organismus oxidativen Stress verhindern können. Oxidativer Stress galt infolge der damit verbundenen Akkumulation von Zellschäden lange als mögliche Ursache für den Abbau der kognitiven Leistungsfähigkeit. Diese Theorie wird jedoch inzwischen von vielen Autoren infrage gestellt. Heute wird häufig die Hormesistheorie favorisiert, der zufolge sekundäre Pflanzenstoffe selbst als Stressoren im menschlichen Organismus wirken und dadurch gesundheitsfördernde Prozesse induzieren: In vitro bewirken sie eine Aktivierung der körpereigenen antioxidativen Abwehr, eine Verstärkung zellulärer Reparaturmechanismen und Unterstützung der Immunabwehr. Für die Empfehlung einer gezielten Aufnahme sekundärer Pflanzenstoffe zur Prävention altersbedingter, neurodegenerativer Veränderungen fehlt derzeit aber noch die wissenschaftliche Grundlage.

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.

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Dipl. Oec. troph. Sebastian Schaffer

National University of Singapore

28 Medical Drive

117456 Singapore

Phone: 0065-65-168159

Email: Sebastian_Schaffer@nuhs.edu.sg