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The effect of elevated protein intake on DNA damage in older people: Comparative secondary analysis of two randomized controlled trials

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posted on 2023-05-03, 22:14 authored by Agnes Draxler, Bernhard Franzke, Johannes Cortolezis, Nicola Gillies, Sandra Unterberger, Rudolf Aschauer, Patrick Zöhrer, Laura Bragagna, Julia Kodnar, Eva-Maria Strasser, Oliver Neubauer, Pankaja Sharma, Sarah Mitchell, Nina Zeng, Farha Ramzan, Randall D’Souza, Scott KnowlesScott Knowles, Nicole Roy, Anders Sjödin, Cameron Mitchell, Amber MilanAmber Milan, Barbara Wessner, David Cameron-Smith, Karl-Heinz Wagner
A high protein intake at old age is important for muscle protein synthesis, however, this could also trigger protein oxidation with the potential risk for DNA damage. The aim of this study was to investigate whether an increased protein intake at recommended level or well above would affect DNA damage or change levels of reduced (GSH) and oxidised glutathione (GSSG) in community-dwelling elderly subjects. These analyses were performed in two randomized intervention studies, in Austria and in New Zealand. In both randomized control trials, the mean protein intake was increased with whole foods, in the New Zealand study (n = 29 males, 74.2 ± 3.6 years) to 1.7 g/kg body weight/d (10 weeks intervention; p < 0.001)) in the Austrian study (n = 119 males and females, 72.9 ± 4.8 years) to 1.54 g/kg body weight/d (6 weeks intervention; p < 0.001)). In both studies, single and double strand breaks and as formamidopyrimidine—DNA glycosylase-sensitive sites were investigated in peripheral blood mononuclear cells or whole blood. Further, resistance to H2O2 induced DNA damage, GSH, GSSG and CRP were measured. Increased dietary protein intake did not impact on DNA damage markers and GSH/GSSG levels. A seasonal-based time effect (p < 0.05), which led to a decrease in DNA damage and GSH was observed in the Austrian study. Therefore, increasing the protein intake to more than 20% of the total energy intake in community-dwelling seniors in Austria and New Zealand did not increase measures of DNA damage, change glutathione status or elevate plasma CRP.


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Draxler, A., Franzke, B., Cortolezis, J. T., Gillies, N. A., Unterberger, S., Aschauer, R., Zöhrer, P. A., Bragagna, L., Kodnar, J., Strasser, E.-M., Neubauer, O., Sharma, P., Mitchell, S. M., Zeng, N., Ramzan, F., D’Souza, R. F., Knowles, S. O., Roy, N. C., Sjödin, A. M., Mitchell, C. J., Milan, A. M., Wessner, B., Cameron-Smith, D., & Wagner, K.-H. (2021). The effect of elevated protein intake on DNA damage in older people: Comparative secondary analysis of two randomized controlled trials. Nutrients, 13, 3479.


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