Nutrition and Health Chapter 4 Notes
Nutrition and Health Chapter 4 Notes NTRI 2000
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This 10 page Class Notes was uploaded by Becky Stinchcomb on Monday February 29, 2016. The Class Notes belongs to NTRI 2000 at Auburn University taught by Dr. B. D. White in Spring 2016. Since its upload, it has received 41 views. For similar materials see Nutrition and Health in Nutrition and Food Sciences at Auburn University.
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Date Created: 02/29/16
Nutrition and Health February 8, 2016 - Carbohydrates, fats, and water (though this is usually associated with vitamins) are the macronutrient group Carbohydrates - Main fuel source for the body - Brain, nerve cells, red blood cells, and exercising muscle need carbs - The body doesn’t not get energy directly from vitamins, minerals, or water - Sources of carbohydrates from within the body: Most of the carbs that we need come from within the body Blood glucose Liver glycogen - About 50% or more our calories needed come from carbohydrates - Cn (H2O) where n can be any number between 3 and 9 because we can only have up to 9 carbons - Carbon Cycle 6 CO2 + 6 H2O + energy C6H12O6 + 6 O2 (photosynthesis) (glucose= carb) CO2 + H2O + light Cn (H2O)n +O2 (general plant photosynthesis ) Cn (H2O)n + O2 energy +CO2 +H2O (animal metabolism) - Simple Carbohydrates- sugars - Complex Carbohydrates- starches and fibers Simple Carbohydrates - Monosaccharides: “mono” means one, this is the basic unit of all carbohydrate structure Glucose, Fructose, Galactose - Disaccharides: “di” means two, formed by the chemical bond of two monosaccharides Maltose, Sucrose, Lactose Glucose - The major monosaccharide found in the body - Derived mainly from the digestion of starches and disaccharides Fructose - Also called fruit sugar - One dietary source is high- fructose corn syrup Sucrose (from sugar cane or sugar beans) glucose + fructose= table sugar Chemically no difference between sucrose and high- fructose corn syrup (no more than 10% of diet is the recommendation for both of them) Galactose - Part of the disaccharide, lactose - Similar to glucose, chemically - Lactose: milk sugar Disaccharides - Maltose: glucose + glucose (when the body digests complex carbohydrates, it forms this) - Sucrose: glucose + fructose - Lactose: glucose + galactose The body cannot absorb disaccharides, they must be broken down into monosaccharides to be digested Sucrose - Glucose + fructose - 2 sources: sugar cane or sugar beets - Derive no more than 10% of calories from here Complex Carbohydrates - Starches and fibers- need to be digested - May contain 1000 or more glucose units - Found in grains, vegetables, and fruits - Some fibers are complex carbohydrates - Starches- found in two forms: Amylose (20%)- a straight chain of glucoses attached head to tail Amylopectin (80%)- branches of glucose Oligosaccharides - Few; glucoses attached together and maybe some other monosaccharides attached together; only 8 – 10 units (middle ground between simple and complex) Making carbohydrates available for body use - Cooking: softens fibrous parts of plants, starch granules swell with water making it easier to digest - Mouth: salivary amylase (breaks down amylose); works at neutral pH’s, but our stomachs are acidic, so not very important for us; might be more beneficial in newborns, who don’t have much acid - Small intestines: enzymes Pancreatic amylase breaks starches in di- and trisaccharides, and oligosaccharides Disaccharides: located in the brush border of the cells that line the inside of the small intestine Maltase, sucrose, lactase dextrinase (breaks down branch points of amylopectin), not in book trehalase (breaks down trehalose which is found in insects) Can also break down things other than just disaccharides (can break down up to 10 glucoses attached together) Lactose Intolerance - Often develops in earlier childhood (3-5 years old) - Caused by a decrease in lactase production - Symptoms: abdominal pain, gas, cramps, and/ or diarrhea after consuming an amount of lactose - For most people it is a matter of how much is consumed; milk products are rich in calcium and Vitamin D Carbohydrate Absorption - Monosaccharides absorbed by intestinal cells using transporter proteins - Glucose and galactose undergo active transport - Fructose undergoes facilitated diffusion - Absorbed by capillaries and taken to the liver by way of the portal vein (only about 10% is not digested) - The liver converts fructose and galactose into glucose - Glucose can be released into the blood and then stored as glycogen or converted into fat Functions of glucose in the body - Supplies fuel (especially for red blood cells and brain) - Spares the bodies supply of proteins from being used - Prevents ketosis (the build up of ketone bodies in the blood) Regulation of blood glucose concentration A person needs 140 glucose/ day to spare the body from ketosis - High blood glucose: pancreas releases the hormone insulin into the blood (then lowers the blood glucose) Insulin causes the liver to store glucose as glycogen Insulin inhibits the liver from making glucose Insulin causes muscle and fat cells to take up glucose In the longer term, insulin will stimulate the production of fat from the stored glucose - Low blood glucose: pancreas releases the hormone glucagon into the blood Glucagon causes the liver to breakdown liver glycogen back into glucose and releases it into the blood Glucagon: causes the liver to synthesize glucose from non- carbohydrate precursors (gluconeogenesis) - Glucose homeostasis Improper regulation of blood glucose concentrations - Hyperglycemia: blood glucose concentration is too high Diabetes: Type 1, Type 2, gestational - Hypoglycemia: blood glucose concentration is too low Reactive hypoglycemia, fasting hypoglycemia Type 1 Diabetes - Often begins in late childhood (used to be called “juvenile onset diabetes” - Generally associated with a decreased release of insulin from the pancreas - An immune system disorder, resulting in the destruction of the insulin- producing cells - Treated primarily by insulin therapy [MISSED WEDNESDAY’S NOTES] Sweeteners - Nutritive Sweeteners Have calories Sugar, sucrose, high- fructose corn syrup, honey Alternative Sweeteners or Artificial Sweeteners - Little or no calories - Eight types are currently available in the United States - Much sweeter than sucrose - FDA determines the Acceptable Daily Intake (ADI) ADIs set at a level 100 times less than the level at which no harmful effects were noted in animal studies - Can be used by adults, children, and are considered safe to use during pregnancy Saccharin - Oldest of the alternative sweeteners - Derived from coal tar - Represents about half of the alternative sweetener market in North America - “Sweet ‘N Low” (pink packet) - 300- 400 times sweeter than sucrose - Provides no calories, but unstable when heated (not safe to be use in cooking) - Has a bitter or metallic aftertaste - Was once thought to increase the risk of bladder cancer and was taken off of shelves but was proven to not be true - ADI: equivalent of 9- 12 packs Aspartame - Made up of two amino acids (aspartate and phenylalanine) - 200 times sweeter than sucrose - Has been approved for use by more than 90 countries and is endorsed by WHO (World Health Organization), AMA (American Medical Association), ADA (American Dental Association) - “Equal” (blue packet) - Has 4 calories per gram and cannot be used for cooking - Products that are made with aspartame have a warning to people with phenylketonuria (PKU) - ADI: equivalent to about 18 cans of aspartame- containing diet soft drinks - Aspartate: amino acid also used in neurotransmitters; during a stroke the body release a large amount of this Sucralose - Sucrose with 3 chlorines attached - “Splenda” (yellow packet) - Has no calories - Cannot be digested - About 600 times sweeter than sucrose - Heat stable so can be used in cooking and baking - ADI: equivalent to about 6 cans of sucralose- containing diet soft drinks Neotame - Similar to aspartame but is heat-stable - Depending upon its food application, it is 7,000- 13,000 times sweeter than sucrose - Does not require a PKU warning because it does not break down when heated - Recently approved so it is only used in very few foods Acesulfame- K - Organic acid linked to a potassium - 200 times sweeter than sucrose - Heat- stable so it can be used in baking - Sometimes it is used in combination with other alternative sweeteners Stevia - Derived from a South American shrub - “Truvia” - 100- 300 times sweeter than sucrose - Heat- stable - Provides no calories Luo han guo - Extract of monk fruit - “Nectresse” and “Monk Fruit in the Raw” - 150- 300 times sweeter than sucrose - Provides some calories, but is considered a zero- calorie product because less than 5 calories per serving Advantame - Approved in May 2014 - Stable at high temperatures - Chemically similar to aspartame but is much sweeter - 20,000 times sweeter than sucrose - Doesn’t require a PKU warning because it doesn’t break down Dietary Fiber - Not a single substance but a group of substances together termed dietary fiber - Group has similar characteristics: mostly made up of indigestible plant polysaccharides - We don’t have the digestive enzymes to break down the chemical bonds that hold the polysaccharides together (example: cellulose) Types of Fiber - Insoluble or non- fermentable fiber: can’t be utilized for energy; insoluble in water Cellulose Hemicellulose Lignins not a plant polysaccharide; polymer of phenol - Soluble or viscous fiber: soluble in water Pectins Gums Mucilages Food Labels - Most food labels don’t separate insoluble and soluble fibers - Functional fiber: fiber added to a food product; resistant to digestion, but fermentable, which stimulates the growth of beneficial bacteria (prebiotic [different from probiotic]) - The definition of fiber was expanded to included the definition of functional fiber Probiotics: foods that already have bacteria in them Healthy Benefits of adequate fiber in the diet - Fiber adds mass to the feces, making elimination much easier; prevents constipation - Constipation can increase the risk of developing: Hemorrhoids Diverticula (diverticulosis diverticulitis) - Fiber can promote a feeling of being full (satiety); may aid in body weight control - Consumption of soluble fibers slows glucose absorption form the small intestine, lowering the need for insulin - Inhibits the absorption of cholesterol and bile acids in bile, lowering blood cholesterol concentrations - Epidemiological (looking for associations without a cause and/ or effect present) studies have suggested a connection between a high- fiber diet and decreased risk of colon cancer DRI for fiber - AI (adequate intake) set to reduce the risk of CV (cardiovascular) disease and perhaps diabetes 25 grams/ day for women 38 grams/ day for men Age + 5 grams for children - DV (daily value): 25 grams/ day for a 2000 calorie/ day diet
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