Diet and Diabetes Risk
Over 1.4 million American are diagnosed with diabetes every year and that the number is expected to rise. Diabetes does not come cheap either. In 2012 diabetes cost $245 billion, 2.3 times what expenditure would without diabetes, still remain the 7th cost of death. The key to improving these statistics is prevention. While moderate exercise and diet consist of healthy fats, fiber, fruits, and vegetables can prevent or delay type 2 diabetes in high-risk patients, there could be a crucial ingredient in recommended diet to making prevention a success; legumes. Already proven to be an important food for people with diabetes, legumes have a low glycemic index, high amounts of vitamin B, and valuable minerals.
Few studies have been performed to assess the association of a diet high in legumes and prevention of diabetes, and those completed have shown inconsistent results. The PREDIMED trial was designed to “examine the association between the consumption of total non-soy legumes and its different subtypes (dry beans, chickpeas, lentil, and fresh peas), and the risk of type2 diabetes development in a Mediterranean population at high cardiovascular risk”. The trial was randomized, multi-center, parallel group trial that included a total of 7447 men and women between the ages of 55-80 who were at high risk for cardiovascular disease and had hypertension, hypercholesterolemia, low HDL, overweight/obese, smoked, or had a family history of premature coronary artery disease. Patients excluded from the study were those who had drug or alcohol abuse, severe chronic illness, allergies to nut or olive oil, and later excluded patients with type 2 diabetes at baseline.
To establish a baseline, each patient has to complete a Food Frequency Questionnaire (FFQ) and measurement of blood pressure, blood samples, and body measurements were taken. The FFQ, along with the other measurements, was taken yearly for a median of 4.3 years to convey long-term diet effects. Patients were split into 4 groups based on legumes consumption and each individual patient was assessed for time to diagnosis of type 2 diabetes, time of death, or to the last check-up. A subsequence analysis was performed to assess the effects to substituting half of a serving of legumes a day for half of a serving of protein.
Out of the 3349 people who were included in the final assessment, 266 developed type 2 diabetes during the defined study period. The average consumption was 19.76 g/d of total legumes with the lowest group consuming 9.4 + 3.55 g/day and the highest group consuming 34.60 + 17.24 g/day. Participants in the highest legume consumption group were less likely to develop type 2 diabetes than those in low consumption group even after adjusting for BMI (HRs: 0.65; 95% CI: 0.43, 0.96; P trend 1/4 0.04). High lentil consumption alone had an approximate decrease in development of type 2 diabetes by 33% compare to those in the low consumption group (HRs 0.67; 95% CI: 0.46-0.98; P trend = 0.05). After assessing the impact of replacing half of the serving of protein with half a serving of legumes a day, there was a trend towards lower risk of type 2 diabetes, but the results were not significant [Meat(HR: 0.58; 95% CI: 0.32, 1.05; P- value =0.07), Fish (HR: 0.59; 95% CI: 0.34, q1.03; P- value =0.07].
While the study demonstrated a statistically significant inverse relationship between consumption and development of type 2 diabetes, areas of weakness limit extrapolation of data to the general population. The study was conducted in Spain and included primarily older caucasian adults. Considering the wide variability in typical diet, type of legumes consumed, and ethnic development of type 2 diabetes, cardiovascular disease risk, a larger and more inclusive study would need to be performed. The rapid rise of diabetes creates a great need for similar studies that show the benefit of diets in legumes reducing the risk of developing type 2 diabetes and possibly other related diseases.
- High legume consumption can lessen the chance of developing type 2 diabetes compare to low legume consumption.
- High consumption of lentils shows the greatest benefit out of all the legumes individually
- A diet high in proteins and p[lant-based foods, as well as moderate exercise, should be recommended to patients with high risk of developing type 2 diabetes and potentially other disease states.
“Statistics About Diabetes.” American Diabetes Association. Web April 6, 2017
“Preventing Diabetes.” Centers for Disease Control and Prevention. November 9, 2016. Web. April 6, 2017.
Becerra-Tomas N, et al., Legume consumption is inversely associated with type 2 diabetes incidence in adults: A prospective assessment from the PREDIMED study, Clinical Nutrition (2017),