Cardiovascular Risk Reduction in Patients with Type 2 Diabetes

A – A1C target

B – Blood pressure target

C – Cholesterol target

D – Drugs for vascular protection

E – Exercise/Eating

S – Smoking cessation

• Is any particular dietary pattern recommended?

There is a large and ever-growing number of dietary patterns that are marketed to improve weight and cardiovascular health. Unfortunately, however, few of these interventions have been studied rigorously, and most dietary interventions are found to be unsustainable in the long term. In the case of motivated patients, there are some specific dietary patterns with high-quality evidence to recommend them. The simplest intervention is the implementation of a vegetarian or vegan diet. Over 18 months, this has been shown to improve fasting glucose and cholesterol profile, and promote weight loss [21]. In another study, a calorie-restricted vegetarian diet led to a reduction in diabetes medication in 46% of participants (versus 5% with conventional diet) [22].

A Mediterranean diet is comprised of large amounts of fruits, vegetables, legumes, nuts, and whole grains. In addition, it includes moderate consumption of olive oil, dairy, fish and poultry, with low consumption of red meat. This dietary pattern has been extensively studied, and in a meta-analysis has been shown to improve glycemic control, blood pressure, and lipid profile [23]. The PREDIMED study evaluated the efficacy of 2 versions of the Mediterranean diet, one supplemented with olive oil or mixed nuts, for reducing cardiovascular events. This multicenter randomized control trial of 7447 participants at high cardiovascular risk (48.5% of whom had diabetes) was stopped early due to benefit. Both versions of the diet reduced cardiovascular events by 30% over 5 years of follow-up [8].

The Dietary Approaches to Stop Hypertension (DASH) diet is similar to the Mediterranean diet in focusing on fruits, vegetables, low-fat dairy, whole grains, nuts, fish, and poultry, while avoiding red meat. In addition, it explicitly recommends avoiding sweets and sweetened beverages, as well as dietary fat. In a trial of patients with diabetes matched for moderate sodium intake, the DASH diet has been shown to decrease A1c, blood pressure, and weight and improve lipid profile within 8 weeks [24,25].

In addition to these specific dietary patterns, specific foods have been shown to improve glycemic control and cardiovascular risk profile, including mixed unsalted nuts, almonds, dietary pulses, and low-glycemic versus high-glycemic index carbohydrates [26–31].

In accordance with CDA, American Diabetes Association (ADA), and European Association for the Study of Diabetes (EASD) guidelines, we recognize that a variety of diets can improve the cardiovascular risk profile of a patient [12,32,33]. Therefore, we suggest a tailored approach to dietary changes for each individual patient. This should, whenever possible, be undertaken with a registered dietitian, with emphasis placed on the evidence for vascular protection, improved risk profile, patient preference, and likelihood of long-term sustainability.

• Should therapy for weight loss be recommended for this patient?

There are currently a number of effective strategies for achieving weight loss, including lifestyle interventions, pharmacotherapy, and surgery. The evidence base for dietary interventions for diabetes is reviewed above. The Look AHEAD study randomized 5145 overweight or obese patients with T2DM to intensive lifestyle intervention for weight loss through promotion of decreased caloric intake and increased physical activity, or usual diabetes support and education. After a median follow-up of 9.6 years, the study was stopped early on the basis of a futility analysis despite greater weight loss in the intervention group throughout the study. However, other benefits were derived including reduced need for medications, reduced sleep apnea, and improved well-being [7].