Macro Nutrients Carbohydrates - PowerPoint Presentation

1. Macro Nutrients Carbohydrates From McArdle, W. Katch, F. Katch, V. Essentials of exercise Physiology (5th edition) 2016 Wolters KluwerFound in Most living cells,Plant sources provide all CHO except for lactose (milk) & a small amount of glycogen which is found in animals

2. Monosaccharide - basic unit of CarbohydrateGlucose – dextrose / blood sugarFormed in plants a) when carbon, hydrogen, water & chlorophyll combine with sunlight b) through breakdown /digestion food (hydrolysis) Immediate Cell energy b) Can be Stored energy (glycogen) in muscle liver c) Can be converted & stored for later use as fat or d) Provides carbon to synthesize non essential amino acidsFructose - considered the sweetest found in honey, tree & vine fruits, root vegetables, berries & flowers a) Energy source b) travels fast in body & readily turns to fat but also glucose in liver Galactose – milk sugar (lactose) & readily converts to glucose for energy metabolism

3. Carbohydrates Stored in liver & muscles as glycogen 1g CHO either as glucose or glycogen = 4kcal of energyMuscle glycogen = main source of energy for all physical activitiesLimited storage capacity & the upper limit = 15g / Kg of body weight Average size person Stores between 1,500 & 2,000 kcal of CHO Well-nourished 80kg person stores 500g CHO 400g in muscle 100g in liver & 2- g in blood as glycogen = energy to run 20miles on level ground

4. DisaccharideTwo Monosaccharides Combined Sucrose = glucose + fructose a)occurs naturally b) found in beet, cane, sugar, & brown sugar, maple syrup & honeyLactose = glucose + galactose a) naturally in milk (milk sugar) Maltose = glucose + glucose fund in cereals & germinating seeds

5. Polysaccharides Plant & Animal Based Plant polysaccharidesStarch – hundreds of sugar molecules large granules in seed, corn cells & grains (breads cereals pastas potatoes roots)Fiber – Non starch = cellulose (most abundant organic molecule on earthProvides structure of plant roots stems leafs seeds & fruit coverings b) found in cell walls as (cellulose) gums, pectin, lignins c) Resist hydrolysis in digestive tract important because fiber has beneficial physiological effects

6. Health Benefits of Fiber Characteristics & Role of Fiber Functional Fiber = nondigestible CHONutrient rich, low energy (caloric) & dense food that1) Holds water & adds volume to food In our gut 2) Contributes to satiety (feeling full) 3) Reduces constipation, diverticular disease & colon cancer by moving food through digestive track 4) Provided fuel to cells of colon5) lower levels of obesity, type II diabetes, hypertension, heart disease & intestinal disorders &https://www.mayoclinic.org/diseasesconditions/diverticulitis/symptoms-causes/syc-203717586) Reduces blood glucose & lipid (fat) levelsWater soluble – preferred & help reduce cholesterol levels & blood lipid levelsFound in rolled oats / oat bran, citrus fruits, apples, carrots, peas Insoluble fibers = cellulose, wheat bran lignin3:1 intake of water soluble to insoluble fiber preferred20-40g daily advised

7. Obesity / Fiber Link Glycemic index – Relative guide as to various carbohydrates ability to raise blood glucose levelsHigh processed low in fiber foods (simple sugar) affect absorption rates of carbohydrates (high glycemic index)High glycemic index foods enter blood fast & elevate blood sugar levelsAffects how hormones (insulin) regulates blood sugar 25% of adults produce excessive insulinExcessive insulin can cause obesity becausehigher levels of glucose oxidation happen instead of fatty acid oxidation Insulin surge causes abnormal decrease in blood glucose, (hypoglycemia)Insulin stimulates fat storage in adipose tissue Hypoglycemia causes urge to eat & very possibly to overeat

8. Glycemic Index Vs. Glycemic Load Glycemic IndexIndicator of CHO containing foods ability to raise blood glucose levels Standard for measurement = white bread or glucose & given a value of 100 or 1Measurement Eating 50g of CHO or food containing CHOAbility to raise blood glucose levels in comparison for a 2 hour time periodApples = glycemic index of 39Eating 50g apple = 50g will raise blood glucose level to 39% of eating 50g of glucose or white breadHigh glycemic index food can be considered healthy (carrots, brown rice, corn) Glycemic LoadQuantifies serving sizes of foods or the available CHO per serving & its glycemic indexReflects greater ability to raisea) blood glucose levelsb) Insulin release in responseFrequent eating of high glycemic load foods are associated witha) Increased risk to type II diabetesb) Coronary artery disease

9. Dietary Trends & Industrialized NationsAmerican diets Generally high in fiber free refined, + animal based & coupled with low levels of plant foods 12-15g of fiber consumed daily National Academy of Sciences (NAS) Recommendations – men = 38g, women = 25g up to age of 50 then 30g & 21g respectfullyWater Soluble = pectin, guar gum & found in apples, carrots, berries,Beans, peas, Legumes, Barley & brown riceNon soluble= cellulose, lignin, hemicellulose wheat bran did not reduce cholesterol levelsCurrent General ConsensusConsume 20-40g of fiber daily at a ratio of 3:1 water soluble to insoluble fibersobesity / low fiber linkhttps://www.nationalacademies.org/fnb/food-and-nutrition-board

10. Exercise & CarbohydratesPrimary Role= energy source for activity – especially intenseReadily converted to fat when Intake exceeds glycogen storage capacityFinding Your Estimated Storage Capacity (grams)Wt. in lb divided by 2.25 Pound to kg Conversion = body. X 15Intense Physical Activity

11. CarbohydratesPrimary Source of Body’s EnergyOnly macronutrient used in both aerobic (long lower intensity) & anaerobic (short higher intensity) metabolismStored glycogen = primary energy source form rest to initial activity Fast source of energy – twice the rate as fats for work done 1st 20 minutes of activity = 40%-50% of energy Long bouts of activity causes glycogen depletion & more fats are used Approximately ½ of energy supplied for light & moderate activity Needed “primer” for fat metabolism as wellHelps to prevent protein & tissue breakdown in the body(Catabolism)

12. CHO & the BrainCHO (glucose) impact on the brain & CNS.CHO Structure = 3 carbon compound Brains primary & almost exclusive fuel source consumes about 120 g / 420 kcal (1760 kJ) daily (2)Approximately 60% of the utilization of glucose by the whole body in the resting state (2)Fatty Acids cannot cross the blood brain barrierBrain, Speech & Importance of Glucose for TasksTaken from http://communica.co.cr/en/Intensive brain tasks – simultaneous interpretation consecutive interpretation or document interpretation Recommended interpreters require adequate supply of glucoseExam taking – may be important as well ask teachers if that is why hard candy / sweets are sometimes given during examsImage from “Interpreters & TranslatorsNeed to consume sugar (glucose)” http://communica.co.cr/en/