Carbohydrate Metabolism & Diabetes PDF

Disorders of carbohydrate metabolism Digestion of carbohydrates The major dietary carbohydrates are:- Sucrose, maltose and lactose (disaccharides) - Starch, glycogen and cellulose (polysaccharides) Digestion of disaccharides (in intestine) by disaccharidases - Sucrose Sucrase glucose and fruc...

Disorders of carbohydrate metabolism Digestion of carbohydrates The major dietary carbohydrates are:- Sucrose, maltose and lactose (disaccharides) - Starch, glycogen and cellulose (polysaccharides) Digestion of disaccharides (in intestine) by disaccharidases - Sucrose Sucrase glucose and fructose - Lactose Lactase glucose and galactose - Maltose Maltase two glucose molecules Digestion of starch Starch is digested into glucose by α-amylase. Glycogen and cellulose digestion • Glycogen breakdown or glycogenolysis occurs by two enzymes glycogen phosphorylase and glycogen debranching enzyme. • Liver breaks down glycogen to maintain adequate blood glucose levels whereas muscles break down glycogen to maintain energy for contraction. • Cellulose cannot be digested due to a lack of appropriate enzymes to break the beta acetal linkages. • The undigested cellulose act as fibers that aids in the functioning of the intestinal tract. Disorders of carbohydrate metabolism: 1. Galactosemia - a rare, hereditary disorder that affects the body’s ability to convert galactose to glucose. 2. Glycogen storage disease 1 – occurs due to deficiency of enzymes involved in glycogenolysis. 3. Hunter syndrome - abnormal accumulation of complex sugars in cells. 4. Hurler syndrome – occurs due to deficiency of a lysosomal enzyme which aids in the breakdown of dermatan sulfate and heparin sulfate. 5. Pompe disease – also known as glycogen storage disease II (occurs due to deficiency of acid maltase) Diabetes mellitus (DM) • Diabetes mellitus is commonly known as diabetes. • It is a metabolic disease that causes high blood sugar. • The hormone insulin (secreted by beta cells of pancreas) moves glucose from the blood into our cells to be stored or used for energy. • With diabetes, our body either doesn't make enough insulin or can't effectively use the insulin it does make. • Function of insulin: Insulin decreases gluconeogenesis. Increased the blood sugar • Hyperglycemia represents the primary symptom of DM. It results from defects in insulin secretion or insulin action or both. • The chronic hyperglycemia of diabetes is associated with long-term damage and failure of various organs, especially the eyes, kidneys, nerves, heart and blood vessels. Normal blood sugar levels Normal Fasting Blood Sugar: 70-110 mg/dl Normal Post-Meal Blood Sugar (Postprandial) • Independent of what a person eat, it must be less than 140 mg/dl two hours after a meal. DIAGNOSIS OF DIABETES 1) Symptoms of diabetes (3 Ps - polyurea, polydipsia and polyphagia) plus a plasma glucose concentration > 200 mg/dl obtained at any time of day and without regard to meals. OR 2) Fasting plasma glucose ≥126 mg/dl (Measured more than one time). OR 3) 2-hour postprandial glucose ≥200 mg/dl (Measured more than one time). Impaired metabolism in Diabetes mellitus • Due to deficient insulin in DM, the glucose utilization by the cells is impaired (its uptake, oxidation and subsequently its breakdown to produce energy). ***Instead of glucose, the cells will use fatty acids (FAs) as a source of energy. • Oxidation of fatty acids produces acids called ketone bodies (KBs). • Excess oxidation of FAs produces more KBs that leads to metabolic acidosis (KETOACIDOSIS). What is HbA1c? • It is the percentage of glycated hemoglobin. • It is used to evaluate a person’s level of glucose control. Categories of DM according to HbA1c levels • Non-diabetic • HbA1c < 5.7% • Pre-diabetes • HbA1c 5.7% - 6.4% • Diabetes • HbA1c 6.5%- 7% = controlled DM • HbA1c > 7% = uncontrolled DM Management plan (3 Ds) Diet Drug Daily Exercise Best diet for a diabetic person ? Drugs Metformin is considered as the first-line drug for treating diabetes. Daily exercise • Improves blood glucose control in diabetes. • Reduces cardiovascular risk factors. • Contributes to weight loss and improves well-being.