1. Carbohydrates

2. Elements in a carbohydrate  Carbon  Hydrogen  Oxygen  Carbohydrates provide the body with energy.

3. Uses of energy in the body  Mechanical energy – movement / work (or examples)  Chemical energy – (metabolism / digestion / absorption)  Heat energy (maintain body temperature)  Electrical energy (transmission of nervous impulses)  Basal metabolism (heartbeat / blood circulation / breathing, etc.)

4. Reasons for reducing the amount of sugar in the diet.  Bacteria act on sugar on teeth and forms plaque  Sugar converted to acid – dissolves enamel / tooth decay  R isk of diabetes (too much glucose in blood for insulin produced)  Gum disease  Breathlessness  Excess sugar converted to fat, stored under skin (adipose tissue) around internal organs  Obesity  CHD ( associated with coronary heart disease)  Low self-esteem  Lethargy

5. Ways of reducing sugar  Avoid adding sugar to drinks (use artificial sweetener)  Fewer sweets/chocolate – biscuits/cakes  Reduce sugar in recipes (use canned fruit in fruit juice instead of syrup)  Drink low calorie drinks/Diet Coke  Avoid fizzy drinks  Do not buy sugar- coated breakfast cereal  Buy ‘sugar free’ products  Fewer convenience foods  Study nutritional information on packaging

6. Forms in which the sugars (carbohydrates) are found: Monosaccharides.  Simple sugars  C 6 H 12 O 6  Basic unit  End product of digestion  Sweet  Soluble in water  Examples of monosaccharides  Glucose  Fructose  Galactose

7. Forms in which the sugars (carbohydrates) are found: Disaccharides.  Double sugars  C 12 H 22 O 11  2 simple sugars combined  Sweet  Soluble in water  Glucose + 1 other simple sugar  Broken down to monosaccharides during digestion  Examples of disaccharides:  Maltose  Sucrose  Lactose

8. Forms in which the sugars (carbohydrates) are found: Polysaccharides.  Made up of many monosaccharides  Insoluble in water  Not sweet  Not all polysaccharides can be digested: Non Starch Polysaccharide (NSP) adds bulk to diet (fibre), prevents constipation/diverticulitis/varico se veins etc., chain is branched, cannot break  Starch can be digested because molecules are linked together in a simple chain.  Examples of polysaccharides  Starch  Glycogen  Pectin  Mucilagescellulos  NSP (Non Starch Polysaccharides)

9. Digestion and absorption of starch In the mouth:  Amylase/ptyalin, from salivary glands, acts on cooked starch converting it into maltose. In the duodenum:  Amylase in pancreatic juice breaks down starch to maltose

10. Digestion and absorption of starch In the ileum:  Enzymes secreted by intestinal juice:  Maltase in intestinal juice converts maltose to glucose  Lactase acts on lactose and converts it to glucose + galactose.  Invertase / sucrase acts on sucrose breaks down it to fructose + glucose  Villi (finger-like projections) in walls of small intestine have walls made of single cells, large surface area and a network of blood capillaries.  Glucose passes through walls of blood vessels into bloodstream, then transported to liver.

11. Release of energy from end product of digestion of starch  Glucose circulated in blood stream; to body cells for cell respiration;  C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + energy  Glucose + oxygen → carbon dioxide + water + energy  Nutrients pass through the villi / finger like projections

12. Importance of NSP  Gives feeling of fullness, limits intake of other nutrients.  Absorbs water in colon, swells, making it bulky  Softens faeces, helps remove waste, easier to expel, regularly.  Stimulates peristalsis ( gives muscles something to grip), remove toxins, binds food residues, lowers cholesterol, prevents constipation  Reduces blood sugar  Reduces risk of hernia, cancer of colon, diverticular disease, haemorrhoids, varicose veins. Non Starch Polysaccharides

13. Sources of NSP  Green vegetables (celery and vegetables), leafy vegetables  Fruit skins and seeds (potato skins, fresh and dried fruit)  Nuts  Pulses, beans  Wholegrain breakfast cereal (brown rice, wholemeal pasta)  Wholemeal bread (not brown bread), wholemeal flour, oats, bran  Maize