Protein intake and cancer: an umbrella review of systematic reviews for the evidence-based guideline of the German Nutrition Society

Tilman Kühn; Nicole Kalotai; Anna M Amini; Julia Haardt; Andreas Lehmann; Annemarie Schmidt; Anette E Buyken; Sarah Egert; Sabine Ellinger; Anja Kroke; Stefan Lorkowski; Sandrine Louis; Matthias B Schulze; Lukas Schwingshackl; Roswitha Siener; Gabriele I Stangl; Bernhard Watzl; Armin Zittermann; Katharina Nimptsch; German Nutrition Society

doi:10.1007/s00394-024-03380-4

Protein intake and cancer: an umbrella review of systematic reviews for the evidence-based guideline of the German Nutrition Society

Eur J Nutr. 2024 Apr 21. doi: 10.1007/s00394-024-03380-4. Online ahead of print.

Authors

Tilman Kühn^{1

2

3

4}, Nicole Kalotai⁵, Anna M Amini⁵, Julia Haardt⁵, Andreas Lehmann⁵, Annemarie Schmidt⁵, Anette E Buyken⁶, Sarah Egert⁷, Sabine Ellinger⁸, Anja Kroke⁹, Stefan Lorkowski^{10

11}, Sandrine Louis¹², Matthias B Schulze^{13

14}, Lukas Schwingshackl¹⁵, Roswitha Siener¹⁶, Gabriele I Stangl¹⁷, Bernhard Watzl¹², Armin Zittermann¹⁸, Katharina Nimptsch¹⁹; German Nutrition Society

Affiliations

¹ The Institute for Global Food Security, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland, BT9 5DL, UK. corresponding_author@dge.de.
² Heidelberg Institute of Global Health (HIGH), Faculty of Medicine and University Hospital, Heidelberg, Germany. corresponding_author@dge.de.
³ Department of Nutritional Sciences, University of Vienna, Vienna, Austria. corresponding_author@dge.de.
⁴ Center for Public Health, Medical University of Vienna, Vienna, Austria. corresponding_author@dge.de.
⁵ German Nutrition Society, Bonn, Germany.
⁶ Institute of Nutrition, Consumption and Health, Faculty of Natural Sciences, Paderborn University, Paderborn, Germany.
⁷ Institute of Nutritional and Food Science, Nutritional Physiology, University of Bonn, Bonn, Germany.
⁸ Institute of Nutritional and Food Science, Human Nutrition, University of Bonn, Bonn, Germany.
⁹ Department of Nutritional, Food and Consumer Sciences, Fulda University of Applied Sciences, Fulda, Germany.
¹⁰ Institute of Nutritional Sciences, Friedrich Schiller University Jena, Jena, Germany.
¹¹ Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD) Halle-Jena-Leipzig, Jena, Germany.
¹² Department of Physiology and Biochemistry of Nutrition, Max Rubner-Institut, Karlsruhe, Germany.
¹³ Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
¹⁴ Institute of Nutritional Science, University of Potsdam, Potsdam, Germany.
¹⁵ Institute for Evidence in Medicine, Medical Center, University of Freiburg, Freiburg, Germany.
¹⁶ Department of Urology, University Stone Center, University Hospital Bonn, Bonn, Germany.
¹⁷ Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
¹⁸ Clinic for Thoracic and Cardiovascular Surgery, Herz- und Diabeteszentrum Nordrhein-Westfalen, Ruhr University Bochum, Bad Oeynhausen, Germany.
¹⁹ Molecular Epidemiology Research Group, Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association, Robert-Rössle-Straße 10, 13125, Berlin, Germany. corresponding_author@dge.de.

PMID: 38643440
DOI: 10.1007/s00394-024-03380-4

Abstract

Purpose: It has been proposed that a higher habitual protein intake may increase cancer risk, possibly via upregulated insulin-like growth factor signalling. Since a systematic evaluation of human studies on protein intake and cancer risk based on a standardised assessment of systematic reviews (SRs) is lacking, we carried out an umbrella review of SRs on protein intake in relation to risks of different types of cancer.

Methods: Following a pre-specified protocol (PROSPERO: CRD42018082395), we retrieved SRs on protein intake and cancer risk published before January 22th 2024, and assessed the methodological quality and outcome-specific certainty of the evidence using a modified version of AMSTAR 2 and NutriGrade, respectively. The overall certainty of evidence was rated according to predefined criteria.

Results: Ten SRs were identified, of which eight included meta-analyses. Higher total protein intake was not associated with risks of breast, prostate, colorectal, ovarian, or pancreatic cancer incidence. The methodological quality of the included SRs ranged from critically low (kidney cancer), low (pancreatic, ovarian and prostate cancer) and moderate (breast and prostate cancer) to high (colorectal cancer). The outcome-specific certainty of the evidence underlying the reported findings on protein intake and cancer risk ranged from very low (pancreatic, ovarian and prostate cancer) to low (colorectal, ovarian, prostate, and breast cancer). Animal and plant protein intakes were not associated with cancer risks either at a low (breast and prostate cancer) or very low (pancreatic and prostate cancer) outcome-specific certainty of the evidence. Overall, the evidence for the lack of an association between protein intake and (i) colorectal cancer risk and (ii) breast cancer risk was rated as possible. By contrast, the evidence underlying the other reported results was rated as insufficient.

Conclusion: The present findings suggest that higher total protein intake may not be associated with the risk of colorectal and breast cancer, while conclusions on protein intake in relation to risks of other types of cancer are restricted due to insufficient evidence.

Keywords: Cancer; Evidence-based guideline; Protein; Umbrella review.

Publication types

Review