HES 2823 1nd Edition Lecture 4 Outline of Last Lecture I Carbohydrates continued A Polysaccharides II Digestion III Blood Glucose Regulation Outline of Current Lecture I Blood Glucose Regulation continued A Blood Glucose Test B Unhealthy Regulation C Glycemic Index Current Lecture I Blood Glucose Regulation Glucose Tolerance Test 160 140 Blood Glucose Concentration in mg 100ml 120 100 80 60 40 20 0 2 1 0 1 2 3 4 Time in hours These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 5 A Blood Glucose Test 1 Fasting occurs before the 0 hour at which point glucose is introduced to the body 2 The levels rise and peak around one hour after food consumption and then return to normal levels between two and three hours after original ingestion 3 Insulin increases by along the same trend as the glucose levels as it instructs body cells to uptake glucose 4 Once the glucose and insulin levels have returned to normal concentrations glucagon levels begin to rise telling the cells to break down the glucagon to prevent glucose levels from decreasing to 0 5 Blood glucose levels should oscillate up and down consistently and mildly B Unhealthy Regulation 1 Diabetes a 10 if US population affected b Hyperglycemia hyper high glyc sugar emia in the blood too much sugar in the blood i Eventually the kidneys begin to clear the blood of glucose excreting the sugar through urine ii Associated with both types of diabetes c Two types i Type 1 Diabetes Sufferers do not produce adequate insulin none or very little Previously called juvenile onset diabetes Causes too much glucose to remain in blood without insulin to tell cells to absorb the carbohydrate CHO Medicated with insulin therapy o Too much insulin can cause blood glucose levels to lower too much resulting in a diabetic coma o Difficult to mimic pancreatic insulin secretions through self medicating ii Type 2 Diabetes Insulin resistant Too much glucose remains in the blood even though insulin is present to tell cells to absorb it Associated with obesity A current US epidemic Medicated with hypoglycemic drugs 2 Hypoglycemia hypo under glyc sugar emia in the blood a Blood glucose concentration levels do not remain high enough causing fatigue headaches and grogginess b Not life threatening c Timely meals prevent any symptoms d Often undiagnosed 3 Glucose Tolerance Test Example a Food A cornflakes i Starch a glucose polymer ii More closely follows the trend of the above graph and the glucose concentration levels because of more pure glucose iii Glycemic Index 90 b Food B chocolate i Sucrose glucose and fructose ii The trending line associated with this food does not rise as significantly as cornflakes because fructose comprises half of the sugar present in the substance iii Glycemic Index 50 C Glycemic Index GI measure of how much a food affects glucose levels in blood when compared to pure glucose 1 Only displays how much glucose is in blood not how much enters cells 2 Only conveys individual food items consumed alone thus it is possible to lower the glycemic index of the initial food when combined with different foods 3 Remember that all monosaccharides are converted to glucose if not already in this form a Example 100 g of starch 100 g of glucose i The starch glucose polymer is digested or broken down into monomers of glucose and delivered to cells with minimal losses b Example 100 g of sucrose 100 g of glucose i The sucrose fructose and glucose is digested broken down into the monosaccharides and the fructose converted to glucose ii The glucose is then delivered to the cells with minimal losses 4 US dietary guidelines for GI from field experts communicate that the GI is irrelevant for average and healthy human being who regulates blood glucose levels normally 5 High and low GI a High GI i Characteristics high starch low fat ii Examples refined grains pastas bread rice corn potatoes b Low GI i Characteristics high fructose high lactose ii Examples dairy fruit c Not every food has an obvious high or low GI d CHO digestion occurs in the small intestine i The more fat in the stomach due to particular food intake the more slowly food is released from the stomach into the small intestine ii This explains why low GI foods do not raise glucose levels as much as high GI foods 6 Functional Use of GI a Long term physical activity endurance do not pertain to brief periods of exercise b Activity in correlation with diet i Exercising during the peak of glucose levels or prior to eating is not best ii Activity after insulin and glucose levels are restored to normal after eating also not best iii Insulin has 2 messages use CHO uptake glucose and do not use fat CHO storage is much smaller than fat storage If one depletes his CHO stores his muscles will lack fuel depending on more energy than present in the blood iv It is best to consume low GI foods before long term physical activity