Homocystein und B-Vitamine im Fokus von Gefäß- und neurodegenerativen Erkrankungen

Zusammenfassung

Hyperhomocysteinämie gilt als etablier­ter Risikofaktor für kardiovaskuläre wie neurodegenerative Erkrankungen. Eine Verminderung des kardiovaskulären Risikos durch Senkung des Homocysteinspiegels mit B-Vitaminen konnte allerdings in vielen Sekundär-Präventions­studien nicht gezeigt werden, möglicherweise aufgrund der fehlenden statistischen Power von Einzelstudien. Metaanalysen mit einer großen Patientenzahl liefern zuverlässigere Aussagen. Eine aktuelle Metaanalyse hat gezeigt, dass das kardiovaskuläre Risiko nur bei Patienten ohne Aspirineinnahme um 7 % signifikant gesenkt wurde. In der Sekundärprävention, wo Aspirin routinemäßig verordnet wird, bewirkt Folsäure daher keine zusätzliche Risikosenkung. Hyperhomocysteinämie ist ebenfalls ein Risikofaktor für Schlaganfall oder stummen Hirninfarkt. Große Meta­analysen berichten für Folsäuretherapie eine milde Prävention von Schlaganfällen, die deutlicher bei nicht sekundärer Präven­tion und Männern gefunden wurde (16 % Risikoreduktion). Eine Verbesserung der kognitiven Leistung durch B-Vitamine ist ebenfalls vielfach gezeigt worden. ­Insgesamt besteht aber großer Forschungsbedarf, um zu zeigen, ob v. a. bei älteren Menschen mittels B-Vitaminen eine Verbesserung kognitiver Leistungen wie auch eine Verzögerung der Entwicklung von Demenzerkrankungen erreichbar ist.

Schlüsselwörter

Homocystein - Demenz - Schlaganfall - Folsäure - Vitamin B₁₂ - Vitamin B₆

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