NUTRITION (Reading from Text) Chapters 1-3 Instructor: Lisa M. Murray, MS
FOOD CHOICES Personal Preference Habit Ethnic Heritage or Tradition Social Interaction Availability, Convenience, and Economy Positive and Negative Associations Emotional Comfort Values Image Nutrition and Health Benefits
Nutrients In Foods and in The Body Composition of Foods Six Nutrient Classes: Water Carbohydrates Lipids Proteins Vitamins Minerals
Foods also contain non nutrients and other compounds Fibers Phytochemicals Pigments Additives Alcohols
Fiber Facts Fiber is primarily found in plants Described as the indigestible husks, seeds, stems, skin and cell walls which hold plants together Two Types: Insoluble Nature’s Laxative Wheat Bran Legumes Corn Bran Fruit and Vegetable Skins
Fiber Facts Soluble Fiber-Heart Helper more palatable than insoluble fiber Soluble Fiber consists of gums and pectins which form a bulky gel in the intestines Pectins are found in Fruits and Gums in stems and seeds Oats and Oat Bran Corn, Barley, Squash Apples, Pears, Prunes, Grapes Dried Peas and Beans Carrots, Yams
Fiber Intake Recommended: 20 grams at least 5x/week Vegetables Green Peas, canned ½ cup: 5.2 grams Carrots, cooked, ½ cup: 2.8 Brussel sprouts, ½ cup: 2.0 Broccoli tops, cooked, ½ cup: 3.0
Fiber Intake Fruits Rasberries, ¾ cup: 3.7 grams Pear, 1 medium: 2.3 g Blueberries, ¾ cup: 1.4 g Banana, ½ medium: 0.9 Breads Whole Bran Cereal, ½ cup: 13 grams Rice Crispies, ¾ cup: 0.2 g Brown Rice, ½ cup: 2 g White Rice, ½ cup: 1 g
Water, Water Everywhere You may be able to survive a long time without food, vitamins, or mineral; however you would only last a day or two without water ½ to 2/3 of your body is made up of water Solvent, lubricator, regulator of body temperature Carries nutrients and wastes to and from cells Aids in digestions and is necessary in all chemical reactions in body metabolism
Bottle Water is Not Just Water in a Bottle! Still Water: non carbonate and can be spring, well or municipal water Spring Water: whether still or sparkling, it seeps or “springs” to the surface from underground aquifers. If it is not labeled “natural” it may have undergone processing, such as addition of minerals. Mineral Water: contains dissolved mineral salts, such as calcium, sodium, magnesium and iron. Distilled Water: is processed and free of almost all mineral salts Artesian Well Water: water that is forced to the surface from a confined underground aquifer by underground pressure through pipes drilled through the upper confining layer of rock Sparkling Water: carbonated, usually by carbon dioxide gas. Club soda is ordinary tap water with impurities removed, then carbonated with a special mixture of minerals added. “Naturally carbonated”: means the water was effervescent at its underground source
Nutrients in Foods and in The Body Composition of the human body Chemical composition of nutrients includes both organic (those that contain carbon) and inorganic(those that do not contain carbon) compounds. Essential nutrients are those the body cannot make or cannot make in sufficient quantities to meet needs. (indispensable nutrients)
The Energy Yielding Nutrients Macro vs. Micro Energy is measured in Calories (calories, kilocalories, kcalories, kcal) Energy from food differs in energy density: Carbohydrates: 4kcal/g Protein: 4kcal/g Fats: 9kcal/g Alcohol: 7kcal/g
PROBLEM SOLVING: How many grams of fat were consumed if a person received 405 kcalories from fat in a day? 45 grams(405 kcal/9kcal/g fat=45 g fat) How many kcalories are in 13 grams of carbohydrates? 52 kcal (13 g carbs x 4 kcal/g carb = 52 kcal) How many total kcalories are in 10 grams of carbohydrates, 4 grams of protein, 6 grams of fat and 7 grams of alcohol? 159 kcal (10 g carb x 4kcal/g + 4 g protein x 4 kcal/g + 6 g fat x 9 kcal/g + 7 g alc x 7 kcal/g= 40+16+54+49=159kcal
PROBLEM SOLVING: If a food item contains 20 grams of protein, how many kcalories will be provided from protein? 20 g x 4= 80 kcalories from protein Meal A provides 250 grams of protein and 40 grams of fat. Meal B provides 250 grams of carbohydrate and 40 grams of fat. How many kcalories are provided by each meal? Meal A: 250 g protein x 4=1000 kcal; 40 g fat x 9=360 kcal; 1000+360=1360 kcal Meal B: 250 g carb x 4=1000 kcal; 40g fat x 9=360 kcal; 1000 + 360=1360 They both have the same number of kcalories!
The Energy Yielding Nutrients Activity in the body is fueled by food as energy is released from bonds within carbohydrate, fat and protein as they are broken down. (metabolism) Excess energy is stored in the body as compounds such as (body fat). Other roles of energy yielding nutrients: building body tissues, and regulating body processes.
Vitamins and Minerals Vitamins are organic, essential nutrients that allow the body to obtain energy from carbohydrate, fat and protein. Minerals are inorganic, essential nutrients that are found in bones, teeth, and body fluids. Water is an indispensable and abundant essential nutrient that participates in many life processes.
SCIENCE OF NUTRITION The study of nutrients in foods and the body’s handling of those nutrients. Nutrition research uses different types of scientific studies to answer questions about nutrition. The scientific protocol is used in conducting research. (tests) Hypotheses and (develops) theories Information based on personal experience is known as an anecdote
Analyzing Research Studies
Correlations and causes in experiments involve studying variables and correlations, or relationships between variables.
Validity: conclusions were supported by the findings
Replication: used to confirm or disprove findings
Nutritional Information and Misinformation Where do we read about it?
Identifying Nutrition Experts
Nutrition in the News
Can be misleading
May report findings prematurely
Dieticians have been educated and trained in nutrition
American Dietetic Association (ADA)
Recommends nutrition education be a part of all health care professionals’ curricula
Registered Dietician (RD) is a qualified expert
Registered Dieticians Maintain up to date registration May use the title of Nutritionist Many states require a license to practice. (LD) Certified nutritionists, certified nutrition consultants, and certified nutritional therapists do not have the same credentials as an (RD) Public health dieticians work for government funded agencies
Nutrition on the Net www.healthfinder.gov www.heathierus.gov/dietaryguidelines www.mypyramid.gov www.nal.usda.gov/fnic www.cfsan.fda.gov www.5aday.gov
Quackery “Satisfaction guaranteed” Quick and easy fixes Natural One product does it all Time tested Paranoid accusations Personal testimonials Meaningless medical jargon
Developed by the DRI Committee
Members are selected from the Food and Nutrition Board of the Institute of Medicine, the National Academy of Sciences, and Health Canada
How much of a nutrient a person needs, is determined by studying deficiency states, nutrient stores, and depletion, and by measuring the body’s intake and excretion of nutrient
Different persons have different requirements
How? Questionnaires, interviews, anthropometric measurements, physical examination of groups of people, food consumption tracking are all ways to evaluate people’s nutritional status.
Dietary Reference Intakes Used to plan and evaluate diets for healthy people Establishing Nutrient Recommendations Estimated Average Requirement (EAR) defines the requirement of a nutrient that supports a specific function in the body for half of the healthy population Recommended Dietary Allowance (RDA) use the EAT as a base and include sufficient daily amounts of nutrients to meet the known nutrient needs of practically all healthy populations. This recommendation considers deficiencies.
Dietary Reference Intakes Adequate Intakes (AI) reflect the average daily amount of a nutrient without an established RDA that appears to be sufficient. Tolerable Upper Intake Level (UL) is a max daily amount of a nutrient that appears safe for most healthy people and beyond which there is an increased risk of adverse health effects.
Planning A Healthy Diet/SIX DIETARY PLANNING PRINCIPLES 1. Adequacy-providing sufficient energy and essential nutrients for healthy people 2. Balance-consuming the right proportion of foods 3. Kcalorie(energy) stored-balancing the amount of foods and energy to sustain physical activities and metabolic needs
Planning A Healthy Diet/SIX DIETARY PLANNING PRINCIPLES 4. Nutrient Density-measuring the nutrient content of food relative to its energy content Empty Kcalorie Foods denote foods that contribute energy but lack nutrients Moderation-providing enough but not too much of a food or nutrient Variety-eating a wide selection of foods within and among the major food groups
Planning A Healthy Diet/SIX DIETARY PLANNING PRINCIPLES 5. Moderation……. Providing enough but not too much of a food or nutrient…. 6. Variety…. Eating a wide selection of foods within and among the major food groups
Dietary Guidelines for Americans Adequacy of nutrients within energy needs Consume foods from all food groups Limit foods that can be detrimental to health Consume a balanced Diet Weight Management Maintain a Healthy body weight Prevention of Weight Gain
Dietary Guidelines Physical Activity Increase energy expenditure and decrease sedentary activities Include cardiovascular conditioning, stretching and resistance exercises Food Groups to Encourage Choose a variety of fruits, vegetables, milk, milk products, and whole grains
Dietary Guidelines Fats Limit Saturated fat, dietary cholesterol, and trans fats Choose monounsaturated and polyunsaturated fat sources Choose lean, low fat or fat free foods Carbohydrates Choose those that are high in fiber Choose products with a minimal amount of sugar added Decrease the risk of dental caries
Dietary Guidelines Sodium and Potassium Choose foods that are low in salt and high in potassium Alcoholic beverages Drink in moderation Some should not consume alcohol Food Safety Wash and cook foods thoroughly and keep cooking surfaces clean. Avoid raw, undercooked, or unpasteurized products
Diet Planning Guides Food Group Plans sort foods into groups based on nutrient content These guides are important in selecting foods for a nutritious diet providing Balance Variety Adequacy Moderation Nutrient Density Kcalorie Control Management
USDA FOOD GUIDE
The recommended intake of each food group depends upon how many kcalories are required
There are different kcalorie requirements for those who are sedentary compared to those who are active
Variety should be the goal when choosing vegetables
There are (5) five subgroups of vegetables
Orange and deep yellow
DiscretionaryKcalorie Allowance Calculated by subtracting the amount of energy required to meet nutrient needs from the total energy allowance Those with discretionary kcalories may eat additional servings, consume foods with slightly more fat or added sugar, or consume alcohol For weight loss, a person should avoid consuming discretionary kcalories
Serving Equivalents Cups are used to measure servings of fruits, vegetables, and milk Ounces are used to measure servings of grains and meats Visualization with common objects can be used to estimate portion sizes 1 ounce of cheese or meat=size of your thumb 3 ounces of meat=size and thickness of a deck of playing cards Medium sized apple or orange=size of tennis ball ½ cup pasta=size of an ice cream scoop 1 tsp. margarine=size of the tip of your thumb
Guidelines to Groceries Grains Refined foods lose nutrients during processing Enriched foods have nutrients added back including iron, thiamin, riboflavin, niacin, and folate. Whole Grain products are not refined. Examples include brown rice and oatmeal Fortified Foods have nutrients added that were not part of the original food.
Vegetables Choose fresh vegetables often Dark green leafy and yellow-orange vegetables are important Good sources of vitamins, minerals, and fiber Be careful to control added fat and salt Legumes
Fruits Choose citrus and yellow-orange fruits Processed fruits are acceptable alternatives to fresh Provides vitamins, minerals, fibers and phytochemicals Fruit juices lack fiber but are healthy beverages Watch energy intakes and fruit “drinks”
Meat, Fish and Poultry Provides minerals, protein and B vitamins Choose lean cuts Textured vegetable protein is a processed soybean protein and can be used in recipes Weighing can be used to determine portion sizes Use low fat cooking methods, and trim and drain fat to reduce fat intake
Milk Dairy foods are often fortified with vitamins A and D Imitation foods that resemble other foods are nutritionally inferior Food substitutes are designed to replace other foods Many lower fat dairy products are available including, fat free, non fat, skim, zero fat, no fat, low fat, reduced fat and less fat milk
Food Labeling is required on almost all packaged foods.
Posters or brochures provide nutrition information for fresh meats and produce
The Daily Values (DV) are based on a 2000 kcalories reference diet.
There are requirements and guidelines for ingredient lists, serving sizes and nutrition facts.
Health and nutrient claims must follow FDA specified criteria
Structure-function claims do not require FDA approval
Label Claims: To Name a Few! Calorie Free: less than 5 calories Low Calories: 40 calories or less Light or Lite: 1/3 fewer calories or 50% less fat than the reference food Fat Free: less than ½ gram fat Low Fat: 3 grams or less fat High Fiber: 5 grams or more fiber Homework-Bring in the food label from your food of choice!
DIGESTION Digestion is the process of breaking down foods into nutrients to prepare for absorption
ANATOMY OF THE DIGESTIVE TRACT Anatomy of the Digestive Tract – Flexible Muscular Lumen
ANATOMY MOUTH Mastication Stimulation of Taste Buds Swallowing Epiglottis After swallowing the food is called a “bolus”
ANATOMY Esophagus leads the bolus to the stomach Sphincter at the upper and lower ends of the esophagus Lower sphincter is called the cardiac sphincter What is the function of a sphincter?
ANATOMY Stomach Adds juices and grinds the bolus to a semi liquid Chyme Pyloric Sphincter Function-regulates flow of partially digested food into the small intestine
ANATOMY Small Intestine The small intestine receives digestive juices from the gallbladder and the pancreas. The three segments of the small intestine are the duodenum the jejunum the ileum.
ANATOMY Large Intestine The large intestine (colon) begins at the ileocecal valve and ends at the rectum and anus. The chyme-What is this? passes by the opening of the appendix.
Muscular Action Includes Peristalsis Stomach Action Segmentation Sphincter contractions
MUSCULAR ACTION OF THE DIGESTIVE SYSTEM Peristalsis pushes the digestive contents along Stomach action involves circular, longitudinal, and diagonal muscles. Segmentation is contractions by circular muscles that contract and squeeze contents to promote mixing with digestive juices. Sphincter contractions open and close passageways. This prevents reflux and controls the passage of contents.
Stomach Function Acts as a storage tank for food Site of food breakdown Chemical breakdown of protein begins Delivers chyme (processed food) to the small intestine
Small Intestine The body’s major digestive organ Site of nutrient absorption into the blood Muscular tube extending form the pyloric sphincter to the ileocecal valve Suspended from the posterior abdominal wall by the mesentery
Secretions of Digestion Includes digestive enzymes that act as catalysts in hydrolysis reactions Hydrolysis: catabolizes organic molecules Carbohydrates Lipids Proteins
Secretions of Digestion Organic molecules are broken down into simpler forms Makes digestion and absorption easier Specific enzymes act at each step of breakdown The opposite of condensation reactions which build larger molecules by bonding
Secretions of Digestion Saliva from the salivary glands moistens foods Gastric juice from the gastric glands includes hydrochloric acid Characteristic? The goblet cells of the stomach wall secrete mucus to protect the walls of the stomach from high acidity
Secretions of Digestion Pancreatic juice contains intestinal enzymes carbohydrase lipase protease bicarbonate bile is produced by the liver stored in the gall bladder acts as an emulsifier to suspend fat
Digestion continues…. Energy-yielding nutrients are disassembled for absorption Vitamins, minerals and water can be absorbed. Undigested residues, including some fibers, continue through the digestive tract and form stool. Recycling of usable materials
Absorption Small Intestine The enormous surface area of the small intestine facilitates nutrient absorption. Nutrients can be absorbed through simple diffusion, facilitated diffusion, or active transport Simple Diffusion Free movement of molecules in aqueous solutions across the plasma membrane Facilitated Diffusion Involves carrier molecules (example: permease is protein transporter) Active Transport Requires energy to pump against chemical gradients
Anatomy of the Absorptive System Villi are fingerlike projections within the folds of the small intestine that move in a wave-like pattern to trap nutrients Microvilli are the microscopic hair like projections on each villi Crypts are the tubular glands that lie between the intestinal villi Goblet cells are located between the villi and secrete a protective thick mucus.
A Closer Look at the Intestinal Cells Specialization of the cells to absorb different nutrients Preparing Nutrients for Transport Water-soluble nutrients and small products of fat digestion are released to the bloodstream. Fat-soluble vitamins and larger fats form chylomicrons and are released to the lymphatic system.
Large Intestine Larger in diameter, but shorter than the small intestine Frames the internal abdomen
Large Intestine Function Absorption of water Eliminates indigestible food from the body as feces Does not participate in digestion of food Goblet cells produce mucus to act as a lubricant
Accessory Digestive Organs Salivary glands Teeth Pancreas Liver Gall bladder
Salivary Glands Mixture of mucus and serous fluids Helps to form a food bolus Contains salivary amylase to begin starch digestion Dissolves chemicals so they can be tasted
Pancreas Produces a wide spectrum of digestive enzymes that break down all categories of food Enzymes are secreted into the duodenum Alkaline fluid introduced with enzymes neutralizes acidic chyme Endocrine products of pancreas Insulin Glucagons
Liver Largest gland in the body Located on the right side of the body under the diaphragm Consists of four lobes suspended from the diaphragm and abdominal wall by the falciform ligament Connected to the gall bladder via the common hepatic duct
Bile Produced by cells in the liver Composition Bile salts Bile pigment (mostly bilirubin from the breakdown of hemoglobin) Cholesterol Phospholipids Electrolytes
Gall Bladder Sac found in hollow fossa of liver Stores bile from the liver by way of the cystic duct Bile is introduced into the duodenum in the presence of fatty food Gallstones can cause blockages
Review… 1. Mouth-mastication 2. Esophagus-conducts food by peristalsis 3. Stomach-digestive enzymes 4. Small Intestine-continued breakdown of nutrients 5. Large Intestine (colon) 6. Defecation
The Digestive Processes
Health and Regulation Probiotics Flora or micro flora Prebiotics Digestive Problems Questions?
Common Digestive Problems Choking Vomiting Diarrhea Constipation Belching Hiccups Heatburn and Acid Indigestion Gastroesophageal reflux Ulcers
Hormones Food enters the stomach Stimulates cells in the stomach wall Release of gastrin Gastrin stimulates the stomach to release HCl When the pH is reached, (1.5) the acid itself turns off the gastrin producing cells The glands stop producing HCl and the system adjusts itself
Hormones Secretin is released due to the presence of chyme in the intestine-this stimulates the pancreas to secrete bicarbonate Pancreas secretes bicarbonate-to alter the acidity of the intestinal contents Cells of the duodenum signal no longer need to secrete secretin, it no longer flows… The pancreas no longer secretes bicarbonate
Hormones Fat in the intestine stimulates cells of the intestinal wall to secrete the hormone CCK This hormone travels through the blood to the gallbladder Signals the gall bladder to contract Gall bladder releases bile into the small intestine CCK also slows GI tract motility Protein and Fat digestion take longer Slowing the process allows the process to reach completion