Diabetes and Blood Glucose Concerns

Diabetes Mellitus (DM) is a group of diseases characterized by prolonged high blood glucose concentrations, called hyperglycemia, which develops due to defects in insulin secretion, insulin action, or both. Insulin is a hormone, which is secreted by the beta-cells of the pancreas, and needed for the use and storage of all 3 macronutrients: carbohydrate, protein and fat.

In 2017 the total prevalence of DM in the US reached 9.4% of the population, and most of this increase in prevalence was type 2 DM in younger age groups.

A person with diabetes does not produce enough insulin anymore, and, or has some degree of insulin resistance (IR) which leads to hyperglycemia. The clinical onset of type 2 DM is often preceded by an asymptomatic period of months or years. During this time the beta-cells undergo gradual destruction, which is associated with intake of excessive calories, increased insulin resistance and a higher than ideal weight.

The morbidity and mortality associated with DM includes:

• acute complications such as hypoglycemia, DKA ( Diabetic Ketoacidosis ) or
• long – term complications or macrovascular diseases ( higher risk of cardiovascular disease; hypertension; lipid /cholesterol abnormalities, or
• microvascular diseases ( diabetic kidney disease, retinopathy /loss of vision,  neuropathy/ nerve damage, for eg in the feet and hands, and gastroparesis (delayed gastric emptying)

All of these can be reduced significantly by early diagnosis and treatment, and MNT for prevention and treatment of DM has tremendous potential.

There are different categories of Glucose Intolerance:

1. Pre-Diabetes
2. Type 1 DM
3. Type 2 DM
4. Gestational (Pregnancy ) DM
5. Other for eg DM associated with genetic syndromes; drug induced; after organ transplantation
   • Pre-Diabetes is associated with a fasting (8hrs) blood glucose of >7.0mmol/L or a blood test hemoglobin A1C (HbA1C) of 5.7 – 6.4%.  This indicates that a high risk of developing DM exists, and implementation of optimal dietary, weight control and exercise habits, should be encouraged with urgency.
   • Type 1 DM accounts for about 5-10% of all DM diagnoses, and is associated with symptoms such as extreme thirst; excessive urination; unexplained weight loss; electrolyte disturbance; and build up of ketones in the blood and urine. Auto immune thyroid disease and coeliac disease occurs with higher frequency in patients diagnosed with type 1 DM. Insulin therapy, self monitoring of glucose levels and MNT prolong insulin secretion but the need for exogenous (injected) insulin increases inevitably.
   • Type 2 DM accounts for +- 90-95% of all cases. Hyperglycemia develops gradually, coupled by the risk of macrovascular and microvascular complications. Most patients have a BMI > 30kg/m2. Type 2 DM is a combination of Insulin Resistance (IR) and beta-cell failure. Endogenous insulin is inadequate to overcome concomitant IR.When the pancreas becomes unable to produce adequate insulin, hepatic (liver) production of glucose increases causing pre-prandial hyperglycemia. Furthermore, glucagon hypersecretion, glucotoxicity, elevation in circulating free fatty acids, and excess intraabdominal obesity follows.
   • Gestational Diabetes (GDM)occurs during pregnancy, which increases the mother’s risk of developing hypertension, risk of premature labour, and for the baby, increased risk to develop diabetes later in life. Excess glucose from the mother crosses the fetal placenta and the fetus’s pancreas responds by releasing extra insulin to cope with the glucose, which is converted to fat, resulting in macrosomia (larger than normal baby). All women not previously known to have DM should be screened for GDM at week 24 – 28 of gestation. It is estimated that 15-25% of mother’s with GDM will develop T2DM  1-2 years after the pregnancy.   For most women diagnosed with GDM, successful treatment includes:
     • regular blood glucose checks, making sure the plasma glucose goals are achieved ( fasting < 5.3mmol/L ; 1hr post meal <   8mmol/L )
     • optimized dietary management
     • regular moderate physical activity
     • monitoring the baby’s growth and development

However, some women may require medication, and insulin is the preferred agent, in both T1DM and T2DM in pregnancy, as it does not cross the placenta.

The management of all types of DM includes Medical Nutrition Therapy (MNT), physical activity, blood glucose monitoring, medications and self-management education and support. Achieving glycemic control is the most important goal of MNT, as it significantly decreases the risk of long-term complications.

The nutrition care process provided by the registered dietetic professional, is a systematic approach to providing high-quality nutrition care, with thorough and skilled assessment of the following:

1. Biomedical data, medical tests, medication prescribed, type of DM, effectiveness of glycemic control, prior to initial consultation, lipid profile; blood pressure; renal function.
2. The patient’s anthropometric measurements (height, weight, BMI, etc); cultural preferences, social activities, education and occupation influence, physical activity, health literacy, beliefs, attitudes, food preference history, serving sizes, snack habits, food availability, supplement use, and more.

In T1DM the nutrition prescription integrates the insulin regime into preferred eating and physical activity, consistency in timing and amount of carbohydrate consumed, to match fixed insulin doses. Furthermore, assisting the patient to adjust pre meal insulin dosage and understand insulin-to-carbohydrate ratios; meeting nutrient requirements with best food options, and cardio protective nutrition intervention.  It is often necessary to adjust the insulin dosage to prevent hypoglycaemia, which most often occurs with moderate to strenuous exercise lasting more than 45-60minutes. For eg a decrease of  1-2 units of rapid / short acting insulin before the period of exercise may be needed. An additional 15g of carbohydrate (for eg in 1x small banana) may be needed for a 30-60min exercise session, depending on the intensity.

In T2DM essential strategies, include dietary and lifestyle changes to improve blood glucose management, dyslipidemia, weight management and blood pressure. Improved food choices, as well as carbohydrate and fat modification, optimal meal patterns, planning, and blood glucose monitoring to determine necessary adjustments, are recommended.

Hypoglycaemia or Non-diabetic Origin

Hypoglycaemia means low blood glucose. Normally the body is remarkably adept at    maintaining fairly steady blood glucose levels, usually between 3.3 and 5.6 mmol/L, despite intermittent ingestion of food. Maintaining normal levels of glucose is important because all body cells, particularly the brain and central nervous system, require a steady and consistent supply of glucose to function properly. The brain depends almost exclusively on glucose for its energy needs.

Postprandial (reactive ) hypoglycaemia can be caused by an exaggerated , late insulin response, caused by insulin resistance, elevated GLP-1, alimentary hyperinsulinemia, renal glycosuria, and various described metabolic conditions.