Carbohydrates: The Energy Nutrient 2001 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning is a trademark used herein under license.
CARBOHYDRATES Functions of Carbohydrates 1. Energy 2. Regulation 3. Structure
Carbohydrates Two kinds: 1. Simple 2. Complex
What are they? Simple Sugars Monosaccharides A 6 Carbon ring with a water attached Monosaccharides = One Sugar 3 Types : glucose, fructose and galactose Which is sweetest?
Monosaccharides Figure 4.2
Simple Sugars 1. Glucose Blood sugar Basic currency of energy in the body Storage = glycogen
Simple Sugars) 2. Fructose Major sugar found in fruit and honey Sweetest monosaccharide Where else is Fructose found in your food? Sunny Delight Cereals Cookies
3. Galactose Simple Sugars Rarely found by itself in food complex with glucose Its ½ of the milk sugar Lactose Lactose = galactose + glucose What does it Mean if you are Lactose Intolerant?
Simple Sugars: Disaccharides Maltose Sucrose Lactose
Disaccharides Figure 4.3
Disaccharides 1. Sucrose Glucose + Fructose Each contain a 6-Carbon ring and water Food Sources: Candies, cake, cookies, table sugar
2. Maltose Disaccharides Glucose + Glucose Uncommon in food sources, except barley Breakdown product of Starch Product of fermentation Alcohol
3. Lactose Disaccharides Glucose + Galactose Milk Sugar Food Sources: Milk, Yogurt, Cheese, Ice Cream One of a very few sugars found in animal products
Oligosaccharides Sources: dried beans, soybeans, peas, lentils Components of cell membranes Humans lack enzymes to digest oligosaccharides causing bloating, cramps, & gas
Complex Carbohydrates Polysaccharides
Complex Carbohydrates Figure 4.4
Complex Carbohydrates Polysaccharides 1- Glycogen Made and found in our bodies Not found in plants Storage form of Carbohydrate in the body Saved for later use Stored in liver and muscle
Complex Carbohydrates Polysaccharides 2- Starches Most common food polysaccharide Long branched or unbranched chain of glucose molecules Food sources of starch: Vegetables: yams, corn, potatoes Legumes: peas, beans Grains: wheat, rice, oats, breads, pasta, barley, rye Unripe Fruit
Complex Carbohydrates Polysaccharides 3- Fiber Only found in plants We don t have fiber digesting enzymes
FIBER What exactly is fiber?
Pick Whole Grains & Whole Wheat!
2 main categories of fiber 1. Insoluble fiber (does not dissolve in water) 2. Soluble fiber
FIBER Water Soluble (Dissolves in water)- form gels What does it do in your body?
Fiber Why can Cows eat grass and digest it for energy but humans can not? Cows have bacteria to break down fiber to glucose energy
Increasing Dietary Fiber Intake
FIBER Poor Fiber Intake Results in: Small waste = moves slow in GI tract Body takes water out of waste => dry and hard stool Must strain to expel this dry, hard waste = Constipation Diverticula Hemorrhoids
Diverticular Disease Caused from: hard, dry feces, characteristic of a low-fiber diet Prevention Diet high in fiber Plenty of fluids Diverticulosis and Fiber Dr. Latifah Al-Oboudi 2011
Decreased Risk for: FIBER Health Benefits:
Dietary Fiber Benefits High water-holding capacities Fermentable fibers
Review: FIBER How can you tell if a food contains any fiber? *Remember NO food from animal sources have fiber Chicken, Eggs, Tuna? Potatoes, whole wheat bread, whole grain cereal, pinto beans, zucchini, apples? *Best Sources:
Carbohydrates: Digestion What happens when you eat a carbohydrate meal: milk, bagel with jam MILK: Bagel: Jam: Lactose (disaccharide) Starch (polysaccharide) Sucrose (disaccharide) Doesn t take much to break down a disaccharide.but what about the starch?
Carbohydrates: Digestion Eat milk, bagel and jam Mouth: Small Intestine: * Now bagel starch = maltose jam = sucrose milk = lactose
Carbohydrates: Digestion Eat milk, bagel and jam Each Disaccharide has its own enzyme that breaks it down to a Monosaccharide Disaccharide Enzyme End Product Maltose Maltase glucose & glucose Sucrose Sucrase glucose & fructose Lactose Lactase glucose & galactose
Carbohydrates How Does Glucose get into our cells? Glucose + Insulin Inside Cells Then, what do we do with it?
Carbohydrates What if cells don t get glucose? No Insulin No glucose in Cells Starved Cells No Insulin Type I Diabetes Require Insulin Not responsive to insulin Type II Diabetes
Metabolism Process by which nutrients are broken down to yield energy or rearranged into body structures
Carbohydrate Energy How does glucose become energy? Each of the 6 Carbon bonds of glucose can be broken for energy End products of carbohydrate energy metabolism: CO2, Water, Energy (4 kcal/g carbohydrate)
Carbohydrates Excess glucose stored as glycogen How much can we store? What foods contain glycogen?
Carbohydrates What if we run out of glycogen stores?
Carbohydrate Energy Use What if I eat 10 bagels, a jar of jam and a carton of milk for breakfast? Eat too much carbohydrate Stored as fat
Carbohydrate Energy What if I didn t eat anything for days or a very low CHO diet? Use up my glycogen stores for energy -Depleted in 24-36 hrs Protein broken into amino acids blood -Form glucose from amino acid -Nitrogen goes to the kidney as waste -Helps provide fuel for brain Fats are not a significant source of glucose
Carbohydrate Energy Consequences of breaking down Protein for Fuel? No storage form of proteins So this takes functional-needed protein from the body How can this be prevented?
The Need for Carbohydrates The DRI committee recommends:
Sugars Health effects of excess sugars Cavities
Don t over indulge limit sugar intake to 10% of calories (200 g for 2,000 kcal diet) Carbohydrates TOO MUCH of a GOOD THING? Think in terms of caloric intake Empty Calories
Carbohydrates TOO MUCH of a GOOD THING? UNPROVEN Health Effects of Excess CHO intake 1. Causes Obesity? 2. Causes Diabetes? 3. Causes Heart Disease? 4. Causes Kids to Misbehave? 5. Causes Criminal Behavior?
Diabetes Do carbohydrates cause diabetes? NO! Type I Less common Pancreas does not make insulin Type 2 Most common and on the rise Linked to being overweight Fat cells are resistant to insulin
Alternatives to Sugar Artificial sweeteners (nonnutritive) vs. sugar alcohols (nutritive sweeteners)
Aspartame Saccharin Artificial Sweetners Sucralose Stevia- Herbal alternative, not approved by the FDA for widespread use
Alternative Sweeteners Figure 4.17
Alcohol Contributes 7 calories/g 2-carbon molecule made from fermented carbohydrates IT IS NOT A NUTRIENT Can adversely affect liver function, caloric intake, absorption, metabolism and excretion.
Alcohol Fermentation Carbohydrate Ethanol