Carbohydrates: Sugars, Starches and Fibres PDF

The Carbohydrates: Sugars, Starches and Fibres FN1070 Week 4: Chapter 4  – The body’s first choice for energy needs – Used as glucose or stored as glycogen – Dietary Sources: – Grains (e.g. Breads/Cereals/Pasta/etc.) Carbohydra...

The Carbohydrates: Sugars, Starches and Fibres FN1070 Week 4: Chapter 4  – The body’s first choice for energy needs – Used as glucose or stored as glycogen – Dietary Sources: – Grains (e.g. Breads/Cereals/Pasta/etc.) Carbohydrates – Beans/legumes – Milk and alternatives – Fruits – Starchy vegetables (e.g.Potatoes/Turnip/Corn/Carrots/etc) Types of Carbohydrates  Monosaccharides The Carbohydrate Disaccharides Family Polysaccharides  – Monosaccharides: (single sugars) – glucose – galactose The Sugars – Fructose (simple carbohydrates) – Disaccharides: (pairs of monosaccharides) – sucrose (glucose + fructose) – lactose (glucose + galactose) – maltose (glucose + glucose)  – Glucose – Blood sugar (dextrose) – Essen2al CHO - main source of energy for brain & nerves – Excreted in the urine by people with diabetes – Fructose – Naturally found in fruit and honey Monosaccharides – Sweeter than sugar – High fructose corn syrup – added to sugar sweetened beverages, desserts, cereals – more on this later – see required reading – Galactose – Part of lactose (milk sugar) – Freed during diges2on  – Sucrose (Fructose + glucose) – Table sugar (beet or cane) – Lactose (Galactose + glucose) – Sugar in milk – Poorly digested by some people (lactose Disaccharides intolerance) – Maltose (Glucose + glucose) – Produced during the breakdown of starches – Important in brewing – Common in a few foods - barley  – Starch – Excellent source of glucose – Storage form of glucose in plants – Long branched and unbranched chains – Fibre Polysaccharides – Structural parts of plant – Indigestible – can’t be broken down by enzymes (complex – Contribute little to no energy carbohydrates) – E.G: cellulose, hemicellulose, pectins, gums – Glycogen – Storage form of glucose in liver & muscles in humans & animals – Food is not a significant source – Highly branched chains FIBRE/FIBER  – Polysaccharides – sugar units held by bonds indigestible by human enzymes – Whole grains, F&V, legumes – Supply valuable vitamins, minerals, phytochemicals, & fiber, with little or no fat – Two types: FIBRE – Soluble (viscous) – Insoluble (non-viscous) – Functional Fibre – Extracted from plants and added to foods/supplements **Important to drink enough water for the fibre you eat (think of a sponge)  Dissolve in water Viscous and form gummy gels Fermentable SOLUBLE Add thickness to foods (e.g., pectin) FIBRE Inside of apples, barley, carrots, legumes, oats, (VISOUS psyllium FIBRE) Help stool formation Have significant cholesterol-lowering effect Helps regulate blood glucose  – Do not dissolve in water – Do not form gel – Less readily fermented INSOLUBLE – Cellulose & hemicellulose in bran, tough, FIBRE (NON- stringy, gritty VISCOUS) – Some legumes, wheat bran, skin on fruits and vegetables, and hull of seeds – Helps to move our stool through the large intestine – HUSK: the outer inedible portion of the kernel – BRAN: the protective fibrous coating around a grain – rich source of fibre – ENDOSPERM: the starchy portion – the kernel is >80% – GERM: nutrient rich inner portion of the grain  1. Lower blood cholesterol (2 ways) – Reduced risk of heart disease – Vacuum like action: Foods rich in viscous (soluble) fibers bind with cholesterol-containing bile in the intestine and then this is carried out in feces FIBRE: – Prevention: Bacterial fermentation of fiber releases small fatty acid that help reduce cholesterol Health synthesis in liver Benefits 2. Blood glucose control – Reduced risk of diabetes – Glucose absorption slowed down when fiber traps nutrients & delays transit to GIT – Prevents surges in blood glucose & insulin levels  3. Healthy weight management – Foods rich in complex CHO – low in fats & added sugars – Promote weight loss – less energy per intake; feeling of FIBRE: fullness, delay hunger Health – Choose fresh fruit, vegetables, legumes, whole grain foods Benefits 4. Lower rates of colon cancer – Increasing dietary fiber intakes protects against colon cancer; under invesDgaDon is fiber’s ability to dilute & speed removal of potenDal cancer-causing agents  5. Maintenance of GIT Health – Cellulose (in cereal bran, F&V) – enlarge & soJen the stools to help prevent cons