Several studies investigated whether the consumption of foods of animal origin affects the risk of haematological malignancies, with conflicting results. To help clarify this issue, we performed a meta-analysis of observational studies published until November 2014 that investigated the association between the consumption of foods of animal origin (red, processed and white meat, fish and seafood, dairy products and eggs) and the risk of non-Hodgkin lymphoma and its major subtypes and multiple myeloma among adults.
We calculated summary relative risks (SRR) and 95% confidence intervals (95% CI) by using random effect models with maximum likelihood estimation.
Overall, 16,525 non-Hodgkin lymphoma and 3665 multiple myeloma cases from thirty-three independent studies were included. We found an association between consumption of red meat and the risk of non-Hodgkin lymphoma (SRR 1.22, 95% CI 1.03-1.44, I(2)=35%). The consumption of fish and seafood was inversely associated with the risk of multiple myeloma (SRR 0.71, 95% CI 0.51-1.00, I(2)=82%), although the between-studies heterogeneity was high. Finally, the consumption of dairy products was positively associated, with borderline significance, with the risk of non-Hodgkin lymphoma (SRR 1.26, 95% CI 0.99-1.60, I(2)=49%).
Foods of animal origin likely play a role in the aetiology of non-Hodgkin lymphoma and multiple myeloma, with red meat and dairy tending to increase the risk, and fish that tends to decrease it. Our findings reinforce the recommendations to reduce the consumption of red meat by replacing it with vegetables, legumes and fish.