1. Lecture 3b- 21 January 2015 CARBOHYDRATES II

2. Overview of lecture 3b Carbohydrates -blood glucose homeostasis -functions of carbohydrates essential or not? -fad diets

3. BLOOD GLUCOSE HOMEOSTASIS P. 106-109 Maintaining blood glucose at normal levels is important -too low-dizzy and weak -too high-fatigued, confused and difficulty breathing Regulating hormones - insulin and glucagon Balancing in normal range - insulin and glucagon

4. Blood glucose homeostasis continued Falling outside normal range -diet does not regulate blood sugar-the body does -diabetes-types 1 and 2 and gestational diabetes-elevated blood glucose -type 1 diabetes -autoimmune attack on pancreatic beta cells -used to be called insulin dependent diabetes mellitus or juvenile diabetes -no cure at the moment -type 2 diabetes -insulin resistance followed by beta cell failure -used to be called-non-insulin dependent diabetes mellitus(NIDDM) or adult onset diabetes -no cure at the moment -gestational diabetes (GDM) -insulin resistance in pregnancy due to excessive weight gain -resolves with medical management -greater risk of type 2 diabetes later on for mum and post-partum child who experienced in utero GDM -hypoglycemia-low blood glucose from too much insulin or not enough to eat

5. Blood glucose homeostasis continued Falling outside normal range continued -but dietary modifications important- -before and after type 2 diabetes, GDM and hypoglycemia sets in -for type 2 diabetes and GDM avoid uneccessary weight gain by dietary change-low fat and rich in complex carbohydrate and fibre -for hypoglycemia-get enough to eat

6. Blood glucose and diet p. 108-9 glycaemia-blood glucose glycaemic index of food-ability to provoke a blood glucose response - effects blood sugar rise -high glycaemic index foods (eg white bread) causes rapid rise in blood glucose followed by quicker drop in blood glucose -lower glycaemic foods (eg whole grain bread) - causes less rapid rise in blood glucose followed by slower drop in blood glucose - may reduce chances of getting or worsening type 2 diabetes -effect of food on blood glucose-if have slow absorption get modest rise in blood glucose and smooth decrease of blood glucose

7. Blood glucose and diet continued P.108-9 -blood glucose dependent on whether carbohydrate eaten alone or as part of a mixed meal -eating small meals often is same as low glycemic index-why?

8. Blood glucose and diet continued page 108 -however, glycemic index is controversial - inadequate science? - determined for relatively few foods - when determined it is based on average of multiple tests with a great deal of variability

9. Blood glucose and diet continued Fad diets -no apples or oranges but bacon and eggs alright-this is not good why?

10. Carbohydrates - essential or not?

11. yes- why? Healthy roles for carbohydrates 1) neural function 2) give structure to molecules 3) metabolically 4) impact on nutrient absorption

12. Carbohydrate functions- healthy Neural function brain and nerves really only set up to use glucose lipids/proteins cannot be used

13. Carbohydrate functions-healthy continued give structure to molecules carbohydrate e.g. glycogen disaccharides oligosaccharides non-carbohydrate e.g. some proteins (i.e. glycoproteins)

14. Carbohydrate functions-healthy continued metabolically -energy-heat/fuel -sparing protein -burning fat

15. Carbohydrate functions healthy continued metabolically continued make other compounds - glycogen - fat - protein (non-essential amino acids) - DNA/RNA

16. Carbohydrate functions-healthy continued Impact on nutrient handling non-absorbable oligosaccharides impair carbohydrase activity starch granules exposed to moist heat and then cooling are less dense and hence less available to enzyme action

17. Unhealthy roles for carbohydrate glycation (glycosylation) of proteins proteins-albumin -hemoglobin lipoproteins blood vessels

18. Unhealthy roles for carbohydrate glycation (glycosylation) of proteins continued albumin glycation or glycosylation can cause tissue breakdown via stimulating chemical messengers

19. Unhealthy roles for carbohydrate glycation (glycosylation) of proteins continued Haemoglobin may set up a chemical reaction that leads to blood vessel breakdown

20. Unhealthy roles for carbohydrate-glycation (glycosylation) of proteins continued Lipoproteins  low good cholesterol  higher bad cholesterol

21. Unhealthy roles for carbohydrate glycation (glycosylation) of proteins continued Blood vessels glucose itself binds to protein in blood vessels-leaky

22. Next lecture - carbohydrates in health and disease Influence of: the diet nutraceuticals functional foods