Dietary factors and all-cause mortality in individuals with type 2 diabetes: a systematic review and meta-analysis of prospective observational studies
Background: Type 2 diabetes is a major health concern associated with mortality. Diet may influence the progression of diabetes; however, systematic reviews are lacking.
Purpose: To systematically summarise the evidence on diet and all-cause mortality in individuals with type 2 diabetes.
Data sources: PubMed and Web of Science were searched until June 2022.
Study selection: Prospective observational studies investigating dietary factors in association with all-cause mortality in individuals with type 2 diabetes.
Data synthesis: We identified 107 studies. Moderate certainty of evidence was found for inverse associations of higher intakes of fish (SRR per serving/week: 0.95; 95% CI: 0.92, 0.99; n=6 studies), whole grain (per 20 g/d: 0.84; 95% CI: 0.71, 0.99; n=2), fibre (per 5 g/d: 0.86; 95% CI: 0.81, 0.91; n=3) and n-3 polyunsaturated fatty acids (per 0.1 g/d: 0.87; 95% CI: 0.82, 0.92; n=2) and mortality. There was low certainty of evidence for inverse associations of vegetable consumption ( per 100 g/d: 0.88; 95% CI: 0.82, 0.94; n=2), plant protein (per 10 g/d: 0.91; 95% CI: 0.87, 0.96; n=3), and for positive associations of egg consumption (per 10 g/d: 1.05; 95% CI: 1.03, 1.08, n=7), and cholesterol intake (per 300 mg/d: 1.19; 95% CI: 1.13, 1.26; n=2). For other dietary factors, evidence was uncertain or no association was observed.
Higher intake of fish, whole grain, fibre and n-3 polyunsaturated fatty acids were associated with all-cause mortality in individuals with type 2 diabetes. There is limited evidence for other dietary factors and thus, more research is needed.