Based on an umbrella review, which is a review of existing meta-analyses, there is strong or highly suggestive evidence that alcohol consumption is positively associated with risk of postmenopausal breast, colorectal, esophageal, head & neck, and liver cancer.1
What is already known? The latest World Cancer Research Fund (WCRF) report shows there is strong convincing evidence that consuming alcoholic drinks increases the risk of mouth, pharynx and larynx cancers, esophageal cancer (squamous cell carcinoma) and postmenopausal breast cancer. Consumption of 30 grams of alcohol or more per day increases the risk of colorectal cancer and 45 grams of alcohol or more per day increases the risk of liver cancer.2
What does this study add? This umbrella review evaluates the robustness of the 860 meta-analyses from the WCRF Report across a large number of food and nutrient associations with risk of 11 types of cancer.
The current study includes all 860 meta-analyses from the latest WCRF report2 to evaluate the quality of evidence for associations between a large range of dietary factors and the risk of 11 types of cancer. Associations for colorectal cancer and breast cancer have the largest number of meta-analyses and the most studied dietary factors are fruits/vegetables and alcohol.
Strong and highly suggestive evidence, mainly for alcohol consumption
Of these 860 meta-analyses, 247 (29%) have statistically significant findings. These are categorized into four evidence groups, namely: strong, highly suggestive, suggestive, and weak evidence.
Based on 10 meta-analyses (1.2%), the authors find strong evidence for the association between alcohol consumption and a higher risk of colorectal cancer and breast cancer. But also between calcium, dairy, and whole grain products and lower risk of colorectal cancer.
Based on another 13 meta-analyses (1.5%), there is highly suggestive evidence that alcohol increases the risk of cancers of the colon, rectum, esophagus, head and neck, and liver. And that the consumption of coffee is associated with a lowerrisk of liver and skin basal cell carcinoma, and that the intake of fruits and vegetables is associated with a lower risk ofhead and neck cancer.
The researchers suggest that additional similar research is unlikely to change current evidence for most found associations. However, they stress it is still critical to continue and enhance research efforts and investments in this field, because diet is a ubiquitous exposure and changes in diet may modify cancer risk.
Moreover, the researchers indicate that future research should focus on new and improved methods (e.g., repeated web-based dietary records, biomarkers of nutritional status) to measure the time-varying nature of nutrition, the role of early life diet, the assessment of overall diet patterns, the investigation of the biological processes involved in the diet–cancer associations, the study of molecular cancer subtypes and outcomes after cancer diagnosis, and the interaction of diet patterns with the environment, behavior, genome, metabolome, proteome, epigenome, gut microflora, etcetera.
- Umbrella review, a review of meta-analyses
- Findings are based on meta-analyses with strong or highly suggestive evidence
- In nutritional epidemiologic research it is difficult to measure consumption of the different dietary factors
- Evidence from experimental research is essential to identify potential causal associations in epidemiology
- Findings are based on a small number of meta-analyses
- Papadimitriou, N., Markozannes, G., Kanellopoulou, A. et al. An umbrella review of the evidence associating diet and cancer risk at 11 anatomical sites. Nat Commun 12, 4579 (2021). https://doi.org/10.1038/s41467-021-24861-8
- World Cancer Research Fund/American Institute for Cancer Research. Diet, nutrition, physical activity and cancer: a global perspective. https://www.aicr. org/research/third-expert-report/ (2018).