Answer 1: Try drinking 2-3 cups of coffee a day (de-caff or regular).
Coffee, caffeine, and risk of type 2 diabetes: a prospective cohort study in younger and middle-aged U.S. women.
Abstract
OBJECTIVE:
High habitual coffee consumption has been associated with a lower risk of type 2 diabetes, but data on lower levels of consumption and on different types of coffee are sparse.
RESEARCH DESIGN AND METHODS:
This is a prospective cohort study including 88,259 U.S. women of the Nurses’ Health Study II aged 26-46 years without history of diabetes at baseline. Consumption of coffee and other caffeine-containing foods and drinks was assessed in 1991, 1995, and 1999. We documented 1,263 incident cases of confirmed type 2 diabetes between 1991 and 2001.
RESULTS:
After adjustment for potential confounders, the relative risk of type 2 diabetes was 0.87 (95% CI 0.73-1.03) for one cup per day, 0.58 (0.49-0.68) for two to three cups per day, and 0.53 (0.41-0.68) for four or more cups per day compared with nondrinkers (P for trend <0.0001). Associations were similar for caffeinated (0.87 [0.83-0.91] for a one-cup increment per day) and decaffeinated (0.81 [0.73-0.90]) coffee and for filtered (0.86 [0.82-0.90]) and instant (0.83 [0.74-0.93]) coffee. Tea consumption was not substantially associated with risk of type 2 diabetes (0.88 [0.64-1.23] for four or more versus no cups per day; P for trend = 0.81).
CONCLUSIONS:
These results suggest that moderate consumption of both caffeinated and decaffeinated coffee may lower risk of type 2 diabetes in younger and middle-aged women. Coffee constituents other than caffeine may affect the development of type 2 diabetes.
Here are some similar earlier research findings:
Coffee consumption and risk for type 2 diabetes mellitus.
Abstract
BACKGROUND:
In small, short-term studies, acute administration of caffeine decreases insulin sensitivity and impairs glucose tolerance.
OBJECTIVE:
To examine the long-term relationship between consumption of coffee and other caffeinated beverages and incidence of type 2 diabetes mellitus.
DESIGN:
Prospective cohort study.
SETTING:
The Nurses’ Health Study and Health Professionals’ Follow-up Study.
PARTICIPANTS:
The authors followed 41 934 men from 1986 to 1998 and 84 276 women from 1980 to 1998. These participants did not have diabetes, cancer, or cardiovascular disease at baseline.
MEASUREMENTS:
Coffee consumption was assessed every 2 to 4 years through validated questionnaires.
RESULTS:
The authors documented 1333 new cases of type 2 diabetes in men and 4085 new cases in women. The authors found an inverse association between coffee intake and type 2 diabetes after adjustment for age, body mass index, and other risk factors. The multivariate relative risks for diabetes according to regular coffee consumption categories (0, <1, 1 to 3, 4 to 5, or > or =6 cups per day) in men were 1.00, 0.98, 0.93, 0.71, and 0.46 (95% CI, 0.26 to 0.82; P = 0.007 for trend), respectively. The corresponding multivariate relative risks in women were 1.00, 1.16, 0.99, 0.70, and 0.71 (CI, 0.56 to 0.89; P < 0.001 for trend), respectively. For decaffeinated coffee, the multivariate relative risks comparing persons who drank 4 cups or more per day with nondrinkers were 0.74 (CI, 0.48 to 1.12) for men and 0.85 (CI, 0.61 to 1.17) for women. Total caffeine intake from coffee and other sources was associated with a statistically significantly lower risk for diabetes in both men and women.
CONCLUSIONS:
These data suggest that long-term coffee consumption is associated with a statistically significantly lower risk for type 2 diabetes.
Read this paper for a possible metabolic explanation for why coffee (or caffeine) protects against Type 2 diabetes:
