NUTR 202 1nd Edition Lecture 7 Ch 4 Carbohydrates, Sugars, Starches, and FibersCarbohydrates primary functions: • Energy• 4 kcal/g• AMDR: 45-65% of kcal8g carbs + 2g fiber = 32 kcal *Fiber does not provide calories. Sources include:• Whole grains• Refined grains• Fruit• Milk• VegetablesRefined grains: milling removes bran and germ; some nutrients are lost during the refining, examples are wheat or white bread, white rice. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Bran: rich in fiber and some vitamins and minerals. At base is the germ/seed- contains heart healthy oils. Endosperm is the main starch component. Refined grains, such as corn flakes or puffed rice, are made largely from the endosperm and are mostly starch. Replace some of the nutrients removed during refining of grain. This is known as: Enrichment (add only some of the nutrients). Replaced nutrients include folic acid, thiamin, niacin, riboflavin, and iron. Different from fortification (nutrients added are not originally in the food). Vitamin D added is not originally from the milk - is to help deficiencies. Not replaced: Includes fiber, magnesium,phytochemicals, and healthy fats.More about nutrient balance than whole wheat, if label says 100% whole grain - all componentsare there without added. Remember MyPlate wants at least half your grains whole grains. Added Refined Sugar: contain calories but lack fiber and other nutrients. Americans typically contains 16% of calories from added sugars. “Empty calories”. Sugars from whole-natural foods such as fruits, vegetables, and milk are more nutrient dense! Recommended maximum of empty calories should be no more than 10 teaspoons of sugar (150 calories). Carbohydrates made up of “sugar units” containing carbon, hydrogen, oxygen; monosaccharide is made up of 1 molecule of sugar. Disaccharides are made of 2 molecules of sugar. BOTH are known as “simple sugars”. Monosaccharides – three types (only these can be absorbed into intestine)• Glucose – blood sugar• Most important for energy• Part of every disaccharide• Fructose-fruit sugar• Sweetest of the sugars• Part of fruits & vegetables• Galactose• Only in a few foods-part of milk sugarDisaccharides:• Maltose – two glucose units (bread or grain products) • Sucrose – glucose + fructose• Lactose – galactose + glucoseTypes of complex carbohydrates=PolysaccharidesStorage form of carbohydrates in animals:• Glycogen• Liver and musclesStorage form of carbohydrates in plants:• StarchComplex carbohydrate that are not capable of being broken down by human digestive enzymes:• Fiber 2 types: Soluble vs. insoluble fiber1. Insoluble fiber• Does not dissolve in water • Bran, skin of produce, brown rice• Provides bulk in the intestine to ease elimination- Prevent constipation, may prevent colon cancer. 2. Soluble fiber • Dissolves in water• Oat, pulp of apples, beans, bananas• Combines with bile to eliminate some fat and prevents elevated blood cholesterol. Decreases cholesterol absorption and synthesis. • Carbohydrate digestion: Ultimate goal: Glucose for absorption and use1. Mouth-some digestion• Enzyme: Amylase 2. Stomach-none• Amylase is inactivated• Role of fiber3. Small IntestineDigestive Enzymes: from pancreasComplete digestion of CHO at the SI villi (monosaccharides)4. Large Intestine:Elimination of undigested starch & fiberModification of intestinal floraDigestion: first occurs in mouth via salivary amylase and breaks down polysaccharides into shorter chains. Then in the stomach salivary amylase is inactivated and no CHO digestion occurs.In the SI break down disaccharides; pancreatic amylases complete break down job. Brush border completes break down to monosaccharides. In LI fiber and other indigestible CHOs are partially broken down  excreted. Lactose: “milk sugar” • Low levels of lactase activity in the Small Intestine• Highest immediately after birth• Declines with age• Lactose intolerance: lactose mal-digestion leads to the following symptoms: nausea, cramps, bloating, diarrhea & flatulence. DUE TO INACTIVITY OF ENZYME LACTASE. Remember this is in the small intestine. Small Intestine: Absorption of monosaccharides through SI villi• Active absorption: Glucose and Galactose• Facilitated diffusion: fructoseFrom lumen of small intestine, monosaccharides: Enter circulatory system to liver which has: Fructose, galactose converted to glucose• Glucose used for energy• Glucose stored as glycogenSent to rest of body via circulatory system (Blood glucose levels