Potato Consumption and Risk of Type 2 Diabetes: Results From Three Prospective Cohort Studies

OBJECTIVE We aimed to elucidate whether potato consumption is associated with a higher risk of type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS We analyzed data in three cohorts consisting of U.S. male and female health professionals without diabetes, cardiovascular disease, and cancer at baseline: 70,773 women from the Nurses' Health Study (1984-2010), 87,739 women from Nurses' Health Study II (1991-2011), and 40,669 men from the Health Professionals Follow-up Study (1986-2010). Potato consumption was assessed quadrennially using validated food frequency questionnaires (FFQs), and we calculated 4-year change in potato consumption from consecutive FFQs. Self-reported T2D diagnosis was confirmed using a validated supplementary questionnaire. RESULTS During 3,988,007 person-years of follow-up, 15,362 new cases of T2D were identified. Higher consumption of total potatoes (including baked, boiled, or mashed potatoes and french fries) was significantly associated with an elevated risk for T2D: the pooled hazard ratio (HR) of T2D compared with <1 serving/week was 1.07 (95% CI 0.97-1.18) for 2-4 servings/week and 1.33 (95% CI 1.17-1.52) for ≥7 servings/week after adjustment for demographic, lifestyle, and dietary factors. In addition, the pooled HRs of T2D for every 3 servings/week were 1.04 (95% CI 1.01-1.08) for baked, boiled, or mashed potatoes, and 1.19 (95% CI 1.13-1.25) for french fries. We further estimated that the HR of T2D was 0.88 (95% CI 0.84-0.91) for replacing 3 servings/week of total potatoes with the same amount of whole grains. Last, in comparison with stable potato consumption, every 3-servings/week increment of potato consumption in 4 years was associated with a 4% (95% CI 0-8%) higher T2D risk. CONCLUSIONS Greater consumption of potatoes, especially french fries, was associated with a higher T2D risk, independent of BMI and other risk factors. Replacement of potatoes with whole grains was associated with a lower T2D risk.