Case study: Type 2 diabetes

Type 2 diabetes mellitus, also known as non-insulin dependent diabetes, currently represents a major threat to human health with an estimated 425 million adult patients and 4 million deaths globally, in 2017. Even though type 2 diabetes is usually detected in adults and is commonly associated with obesity and other metabolic alterations, its presence is increasing among young subjects.

Accrued evidence indicates that type 2 diabetes can be largely prevented or managed through adherence to a healthy lifestyle and a high-quality diet. Overall, there is no consensus on the relative proportions of macronutrient intake that should be applied for people suffering from prediabetes, fasting glycemia or diabetes, but some general advice is agreed upon. One example is that of the Obesity Society which recommends a diet comprising approximately 30% energy from total fat, 15% to 35% from protein, and 45% to 65% from carbohydrates for the management of type 2 diabetes. Another example is the Mediterranean diet, which has been associated with benefits for several metabolic diseases including type 2 diabetes.

Whilst it’s considered a high-fat diet with 40% energy from total fat, it’s also rich in monounsaturated fatty acids and low in saturated fat. Some investigators attribute this association to the high-intake of olive oil typical of Mediterranean countries, but appropriate trials are still lacking evidence. One exception is the clinical trial PREDIMED which is the only one to date that demonstrated lower incidence of type 2 diabetes in cardiovascular patients. Allocated to a Mediterranean diet further enriched with olive oil.

Any dietary intervention must be designed by the patient’s primary care physician or specialist. The goals are to ensure proper glycemic control, reach or maintain an optimal body weight which equates to BMI of 18.5 to 24.9 kilogrammes per metre squared, maintain an ideal nutritional status, maintain an overall well-being status in which diet is one of the many factors, and address any cardiovascular risk factors to avoid vascular complications. Strict control of caloric intake is the first therapeutic approach to type 2 diabetes. In particular, patients with type 2 diabetes should consume total daily calories, an amount sufficient to attain or maintain a healthy weight, which is often in the 15 to 30 kilocalories per kilogramme per day range.

Nutritional therapy should be implemented to control the glycemic response to meals and to achieve haemoglobin A1C and blood glucose levels as close to the target range as possible, without risk to the individual patient. Carbohydrates should primarily be in their unprocessed forms, which are provided by a target of 8 to 10 servings per day of vegetables, particularly raw fruits and legumes with attention being paid to limit simple sugars or foods that have a high-glycemic index. And to compose a diet with an overall low-glycemic load. Insulin dosing should be synchronised with carbohydrate intake.

Patients with type 2 diabetes who are treated with the short-acting oral hypoglycemic agents, such as nateglinide or repaglinide, should also synchronise carbohydrate intake with administration of these medications. In summary, it is necessary to exercise regularly and keep caloric intake under control to prevent type 2 diabetes. This is especially important in overweight subjects who represent 80% to 90% of all type 2 diabetes patients. And they should follow a hypercaloric dietary regime with a high proportion of fibres, particularly hydrosoluble ones and a low-glycemic load. The use of alcohol and comfort foods should be discussed with a GP or specialist.