Han et al., 2019
Han, M. A., Zeraatkar, D., Guyatt, G. H., Vernooij, R. W., El Dib, R., Zhang, Y., ... & Johnston, B. C. (2019). Reduction of red and processed meat intake and cancer mortality and incidence: a systematic review and meta-analysis of cohort studies. Annals of Internal Medicine, 171(10), 711-720.
https://www.acpjournals.org/doi/full/10.7326/M19-0699?journalCode=aim
- 7 studies on overall cancer mortality for unprocessed meat found an RR of 0.93 (0.91-0.94) for a reduction in 3 portions per week (360 unprocessed, 150 processed) for processed: 0.92, 0.89-0.1.04, 3 studies. One serving was 120 g for unprocessed red meat, 50 g for processed meat
Background:
Cancer incidence has continuously increased over the past few centuries and represents a major health burden worldwide.
Purpose:
To evaluate the possible causal relationship between intake of red and processed meat and cancer mortality and incidence.
Data Sources:
Embase, Cochrane Central Register of Controlled Trials, Web of Science, CINAHL, and ProQuest from inception until July 2018 and MEDLINE from inception until April 2019 without language restrictions.
Study Selection:
Cohort studies that included more than 1000 adults and reported the association between consumption of unprocessed red and processed meat and cancer mortality and incidence.
Data Extraction:
Teams of 2 reviewers independently extracted data and assessed risk of bias; 1 reviewer evaluated the certainty of evidence, which was confirmed or revised by the senior reviewer.
Data Synthesis:
Of 118 articles (56 cohorts) with more than 6 million participants, 73 articles were eligible for the dose–response meta-analyses, 30 addressed cancer mortality, and 80 reported cancer incidence. Low-certainty evidence suggested that an intake reduction of 3 servings of unprocessed meat per week was associated with a very small reduction in overall cancer mortality over a lifetime. Evidence of low to very low certainty suggested that each intake reduction of 3 servings of processed meat per week was associated with very small decreases in overall cancer mortality over a lifetime; prostate cancer mortality; and incidence of esophageal, colorectal, and breast cancer.
Conclusion:
The possible absolute effects of red and processed meat consumption on cancer mortality and incidence are very small, and the certainty of evidence is low to very low.