HLTH 1322 - module one
"Bob's snack contains a total of 234 calories. Calculate the percentage of calories in his snack from each of the energy nutrients you calculated in above question
a) % calories from carbohydrate: 96/234 x 100 = 41% b) % calories from protein: 48/234 x 100 = 21% c) % calories from fat: 90/234 x 100 = 38%
Scientific Process
process by which scientists formulate a hypothesis, gather data by observation and experimentation, and come to a conclusion. o Observation measurement --> hypothesis --> experiment --> observation measurement --> new/revised hypothesis --> experiment --> observation measurement --> substantiated hypothesis
"Bob ate an afternoon snack of two mozzarella cheese sticks and one medium-size apple, totaling 234 calories. This snack contained the following energy nutrients: Fat: 10 grams Carbohydrate: 24 grams Protein: 12 grams" How many calories from the energy nutrients are in Bob's snack? Include the calorie value per gram of each nutrient in your answers.
a) Fat calories: 10g fat x 9 kcal per gram = 90kcal b) Carbohydrate calories: 24g carbohydrate x 4 kcal per gram = 96kcal c) Protein calories: 12g protein x 4 kcal per gram = 48kcal
A range of intakes for a particular energy source that is associated with a reduced risk of chronic disease while providing adequate intakes of essential nutrients
acceptable macronutrient distribution range (AMDR)
the movement of substances into or out of cells against concentration gradient. require ATP and carrier protein
active transport
the nutrient intake that appears to sustain a defined nutritional state or some other indicator of health (e.g. growth rate or normal circulating nutrient values) in a specific population or subgroup
adequate intake (AI)
Practices typically used instead of conventional medicine
alternative
• Information based on personal experience is known as an _______ and is not scientifically based.
anecdote
cell culture studies
another way to study nutrition is to isolate specific types of cells and grow them in a lab. Then use these cells to study effects of nutrients or other components on metabolic processes in a cell.
nutrition assessment involves four major evaluations:
anthropometric measurements, biochemical tests, clinical observations, and dietary intake
a substance that combines with or otherwise neutralizes a free radical, thus preventing oxidative damage to cells and tissues
antioxidant
What does it mean to be organic?
any compound that contains carbon except carbon oxides, sulfides, and metal carbonates (crops grown without synthetic fertilizers or chemicals.)
Additives in functional foods must be on
approved list (GRAS list)
clinical trials - also called intervention studies
are controlled studies where some type of intervention (nutrient supplement, controlled diet, exercise program) is used to determine its impact on certain health parameters. include experimental group and control group
The vascular system consists of
arteries, capillaries and veins.
Megadose vitamin or mineral therapy has not yet
been proven effective in the treatment of cancer, colds, or heart disease.
a measure of the extent to which a nutrient becomes available to the body after ingestion and thus is available to tissues
bioavailability
naturally occurring plant chemicals, esp. from citrus fruits, that reduce permeability and fragility of capillaries
bioflavonoids
Macro minerals include
calcium, chlorine, magnesium, phosphorus, potassium, sodium, and sulfur
animal studies
can provide preliminary data that can often lead to human studies or can be used to study hypotheses that cannot be tested on humans
sources of energy =
carbohydrates, fats, proteins
investigations that use a group of people with a particular condition rather than a randomly selected population
case control studies
investigations that use a group of people with a particular condition rather than a randomly selection population
case control studies
The blind pouch at the beginning of the large intestine into which the ileum opens from one side and which is continuous with the colon is called the _____.
cecum
the responses of the parasympathetic nervous system to the sight, smell, thought, and sound of food
cephalic phase responses
a hormone produced by cells in the small intestine that stimulates the release of digestive enzymes from the pancreas and bile from the gallbladder
cholecystokinin
Stomach adds juices and grinds the bolus to a semiliquid mass called ______.The pyloric sphincter regulates the flow of partially digested food into the small intestine.
chyme Secretions: - Hydrochloric acid • Prepares protein for digestion • Activates enzymes - Pepsin • Begins protein digestion - Gastric lipase • Some fat digestion - Gastrin (hormone) • Stimulates gastric secretion and movement - Intrinsic factor • Needed for absorption of vitamin B12
layers of smooth muscle that surrounds organs, including the stomach and the small intestine
circular muscle
studies that collect large amounts of data to evaluate the effectiveness of a treatment
clinical trials
portion of large intestine extending from the cecum to the rectum
colon
case-control studies
compare case subjects to control subjects they are small-scale epidemiological studies in which individuals who have a condition are compared with similar individuals who do not have the condition.
epidemiological study
compares disease rates among population groups and attempts to identify related conditions or behaviors such as diet and smoking habits. the results of these show correlations
What is gastroesophageal reflux disease?
condition in which gastric contents move backward (reflux) into the esophagus, causing pain and tissue damage
connections co-occuring more frequently than can be explained by chance or coincidence but without a proven cause
correlations
a single set of nutrient intake standards developed by the food and drug administration to represent the needs of "typical" consumer; used standards for expressing nutrient content on food labels
daily values
- Gastric inhibitory peptide (GIP)- released by intes. mucosal cells, ______ gastric secretions and motility, emptying. _____ insulin release from pancreas, required for ______ _______
decreases increases glucose utilization
exchange lists
diet-planning tools that organize foods by their proportions of carbohydrate, fat, and protein. Foods on any single list can be used interchangeably. used often for diabetics
a framework of dietary standards that includes EAR, RDA, AI, UL
dietary reference intakes (RDIs)
a set of values for the recommended intake of nutrients
dietary standards
dietary supplements are regulated according to the
dietary supplement health and education act of 1994 (DSHEA) they do not need premarket approval
herbal supplements
dietary supplements containing plant extracts
substances released at different places in the GI tract to speed the breakdown of ingested carbohydrates, fats, and proteins into smaller compounds that can be absorbed by the body
digestive secretions
: "an impairment of the normal state of the living animal ... that interrupts or modifies the performance of the vital functions."
disease - Food choices are most likely to affect our risk for developing chronic diseases.
what are considered to be the gold-standard of nutrition studies
double-blind, placebo-controlled clinical trials
a condition also known as upset stomach or indigestion; refers to difficulty with digestion
dyspepsia
List the environmental factors that influence our food choices (6)
economic, lifestyle, availability, cultural influences, religion, socio-ecological model
agents that blend fatty and watery liquids by promoting the breakup of fat into small particles and stabilizing their suspension in aqueous solution
emulsifiers
vitamins regulate body processes such as
energy metabolism, blood clotting, calcium balance
to add vitamins and minerals lost or diminished during food processing, particularly the addition of thiamin, riboflacin, niacin, folic acid, and iron to grain products
enrich
network of nerves located in the gastrointestinal wall
enteric nervous system
Hormones act as messengers, and those involved in the GI tract are known as
enterogastrones.
Recycling of certain compounds between the small intestine and the liver is called _____.
enterohepatic circulation
the opening between the esophagus and the stomach that relaxes and opens to allows the bolus to travel to the stomach, and then closes behind it. Also acts as a barrier to prevent the reflux of gastric contents
esophageal sphincter
the tube allowing bolus passage to stomach. There are 2 sphincters at the upper and lower ends of the esophagus
esophagus Upper esophageal sphincter Lower esophageal sphincter (cardiac sphincter)
substances that must be obtained in the diet because the body can either not make them or cannot make adequate amounts of them
essential nutrients
substances that must be obtained in the diet because the body either cannot make them or cannot make adequate amounts of them
essential nutrients
What is the difference between an experimental and control group?
experimental group: a set of people being studied to evaluate the effect of the intervention. Control group: a set of people used as standard of comparison to the experiment group. They have similar characteristics to the experimental group people and are selected at random.
list 13 vitamins
fat soluble (4) = A, D, E, K water soluble (9) = Vitamin C, thiamin (B1), riboflavin (B2), niacin (b3), pyridoxine (b6), cobalamin (b12), folate, pantothenic acid, biotin
If small intestine is damaged, or significant sections removed,
malabsorption and deficiencies can occur.
doses of nutrient that are 10 or more times the recommended amount
megadoses
inorganic compounds needed for growth and regulation of body processes
minerals
absorption =
movement of molecules across the lining of the GI tract and into circulation
the innermost layer of a cavity. The inner layer of the GI tract also called the intestinal wall. It is composed of epithelial cells and glands.
mucosa
The inner lumen of the GI tract is lined with _______. • Within the
mucosa mucosa of the mouth, stomach, and small intestine, are tiny glands that secrete digestive juices, which contribute to the chemical breakdown of food
• Specialized cells allow absorbed materials to cross the
mucosa into the blood, where they are carried off in the bloodstream to other parts of the body.
• Dimension or surface area of small intestine is increased: 3 fold by __________ And another 10 fold by ______ And another 20 fold by _______ All together, these features result in a 600 fold increase in absorptive area of the small intestine! • This means the about 10 foot long small intestine has an absorptive surface area of about _____square yards!
mucosal folds villi microvilli 300
A dislike for anything new or unfamiliar is called
neophobia
a family of more than 25,000 molecules found in chromosomes, nucleoli, mitochondria, an the cytoplasm of cells
nucleic acids
• The enormous surface area of the small intestine facilitates
nutrient absorption.
if a dietary supplement product label contains the words, high in vitamin E, what type of claim is it making? what other claims can be made?
nutrient content claim other: health & structure/function claims
a description of the healthfulness of foods.
nutrient density
any substance in food that the body can use to obtain energy, synthesize tissues, or regulation functions
nutrients
essential chemicals in food
nutrients
The study of how nutrition and genetics interact to influence health is called _____.
nutrigenomics
the science of foods and their components (nutrients and other substances), including the relationship to health and disease (actions, interactions, and balances) processes within the body (digestion, ingestion, absorption, transport, functions, and disposal of end products); and the social, economic, cultural, and psychological implications of eating =
nutrition
process of determining the overall health of a person related to nutrition =
nutrition assessment
- First appeared in 1994 as a result of the Nutrition Labeling and Education Act passed by Congress in 1990 (NLEA)
nutrition facts panel
circumstances in which a person lives, works, and plays that promote overconsumption of calories and discourage physical activity and calorie expenditure
obesogenic environment
Dietary Supplements: How much to take?
Moderate levels advised, no more than 100% DV, unless otherwise instructed by doctor (up to 150% DV) Look for brands that contain at least 20 vitamins and minerals
How do DGA guidelines use core nutrition planning concepts to help us implement guidelines?
- Follow a healthy eating pattern that accounts for all foods and beverages. ABMV - Consume less than 10 percent of calorie/day from added sugars. CDM - Consume less than 10 percent of calories/day from saturated fats. CDM - If alcohol consumed, use moderation. BM - Meet the Physical Activity Guidelines. BC
Proposed explanation made on the basis of limited evidence as a starting point for further investigation
- Hypothesis The Scientific Process enables researchers to test the validity of hypotheses
• Hormonal system (chemical messengers)
- Increase or decrease GI motility and secretions - Influence appetite - Can be growth factors for mucosa and pancreas
• Nutrition on the Net (Internet, World Wide Web, www, cyberspace, websites)
- Internet information can be published by ANYONE. - May be high-quality information: National Library of Medicine's PubMed - May be misleading, incomplete, and totally inaccurate!
The lymphatic system consists of one-way vessels to transport fluids.
- Lacteals are the lymphatic vessels of the intestine that absorb fat-soluble nutrients and pass them to the lymphatic system. - Lymph is a clear, yellowish fluid without red blood cells or platelets that moves through the body in lymphatic vessels by muscle contractions. - The thoracic duct is the lymph's access entry into the subclavian vein, the entry point to the vascular system.
Identifying Fake Credentials
- Look for a degree from an accredited college or university. - Be careful of correspondence schools. - Fraudulent businesses may provide false credentials.
Minerals
- Macrominerals and trace minerals - Functions • Structure, regulation (like fluid balance) - Food sources • All food groups
• Salivary glands
- Moisten and lubricate foods - Secretes digestive enzymes
water
- Most important nutrient - Functions • Structure, regulation - Food sources • Beverages • Foods
• Peptic ulcers can be gastric or duodenal.
- Most ulcers now known to be caused by Helicobacter pylori (H.pylori) infection, not stress. • Strategies - Take prescribed medicine- antibiotics/ antacids - Avoid caffeine- and alcohol-containing foods. - Minimize use of aspirin and ibuprofen - No smoking
Peristalsis and segmentation help to break up, mix, and move food through the GI tract
- 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 along the GI tract with alternate forward and backward movement of contents, thereby breaking apart chunks of the food mass and mixing with digestive juices. - Sphincter contractions open and close passageways. This prevents reflux and controls the passage of contents.
How are DRIs Used?
- Population groups • Assess adequacy of intake • Plan diets • Set policy and guidelines -Individuals • Use RDA and AI as target levels for intake • Avoid intake above UL
Meat, fish and poultry
- Provide minerals, protein and B vitamins - Choose lean cuts. - Textured vegetable protein is processed from soy bean and can substitute for meat in recipes. - Weighing is one way to determine portion sizes. - To reduce fat intake from meats, trim cuts, drain fat and use low-fat cooking methods like: roasting, grilling, broiling
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. Can you name two examples? whole grain oatmeal, brown rice. - Fortified breads and cereals have nutrients added that were not part of the original food.
• Nervous system
- Regulates GI activity in two ways • Local regulation: enteric nervous system • Central nervous system: autonomic nervous system branch of CNS- carries signals to and from GI tract via vagus nerve.
represents the range of intakes for energy nutrients that provide adequate energy and nutrients and reduce risk of chronic disease.
Acceptable Macronutrient Distribution Range (AMDR)
"ABCDMV"- a closer look: —providing enough energy and essential nutrients for healthy people =
Adequacy
Amount thought to be adequate for most people - AI used when EAR and RDA can't be determined
Adequate Intake (AI)
double-blind study
An experiment in which neither the participant nor the researcher knows whether the participant has received the treatment or the placebo
Name three chronic diseases that consuming functional foods may help prevent.
Any three of the following: cancer, hypertension, heart disease, and diabetes. Consuming functional foods also may reduce the incidence of age-related macular degeneration and gastrointestinal disorders.
fruit
Focus on citrus and yellow-orange fruits. - Provide vitamins, minerals, fibers and phytochemicals. - Processed fruits are acceptable alternatives to fresh. - Fruit juices lack fiber but are considered healthy beverages. - Watch energy intakes and fruit "drinks."
Gas/Flatus -
From bacterial breakdown of undigested carbohydrates
Both the nervous system and the hormonal system regulate
GI tract processes.
a hormone released from the walls of the duodenum that slows the release of stomach contents into the small intestine and stimulates release of insulin from the pancreas
Gastric inhibitory peptide (GIP)
the preventive or therapeutic use of high-dose vitamins to treat disease
orthomolecular medicine
Four roads to nutrient absorption
passive diffusion facilitated diffusion active transport endocytosis • Nutrients' different properties determine which of these processes are used in order for them to be absorbed. • The specialized anatomy of the small intestine provides the setting for all these absorption mechanisms to occur efficiently
list four mechanisms involved in nutrient absorption
passive diffusion, facilitated diffusion, active transport, and endocytosis
What begins the digestion of protein?
pepsin
digestion involves both
physical and chemical processes
Substances in plants that may possess health-protective effects, even though they are not essential for life
phytochemicals
compounds that have weak estrogen activity in the body
phytoestrogens
Identifies amount of food we need • Recommends best food sources • Identifies components in food that are helpful or harmful • Helps us make better choices • Improves our health • Reduces our risk of disease • Increases our longevity
The Science of Nutrition
an inactive substance that is outwardly indistinguishable from the active substance whose effects are being studied
placebo
- The _____ vein directs blood rich in absorbed water-soluble nutrients from the GI tract to the liver. - The ______ vein takes blood from the liver to the heart. - The liver acts a "gatekeeper" • Major metabolic organ • protects against toxic substances.
portal hepatic
a circular muscle that forms the opening between the stomach and the duodenum. It regulates the passage of food into the small intestine
pyloric sphincter
the muscular final segment of the intestine, extending from the sigmoid colon to the anus
rectum
the lowest continuing intake level of a nutrient that prevents deficiency in an individual
requirement
what begins the digestion of starch?
salivary amylase
the standard nutrition facts panel shows information on which nutrients?
saturated and trans fat (total fat), cholesterol, sodium, carbohydrates, protein, vitamin D, calcium, iron, potassium.
The Dietary Guidelines recommend reducing intake of
saturated and trans fats, sodium and added sugars. Reducing alcohol intake is another strategy.
an intestinal hormone released during digestion that stimulates the pancreas to release water and bicarbonate
secretin
list the personal preferences that influence food choices (7)
sensory influences (taste, smell, texture) habit, comfort/discomfort foods, food advertising and promotion, eating away from home, food and diet trends, social factors, and nutrition health and belief.
a smooth membrane composed of mesothelial layer and connective tissue
serosa
• The gastrointestinal (GI) tract is the flexible muscular tube from mouth to anus. The outer surface is the ________, while the ______ is the inner space of the tract, through which food moves.
serosa lumen
Cholecystokinin (CCK) targets gall bladder to contract, pancreas to secrete enzymes, and _____ gastric emptying
slows
Chyme mixes with digestive juices from the gallbladder and the pancreas
small intestine
Digestion and absorption of nutrients takes place all along the GI tract as a result of physical and chemical processes, with the _____ ______ being where most of this occurs.
small intestine
Most nutrients absorbed here, including carbohydrates, protein, fats and vitamins and minerals
small intestine
Where in the GI tract does the majority of nutrient digestion and absorption take place?
small intestine
micronutrient over-consumed by americans of all ages
sodium
circular bands of muscle fibers that surround the entrance or exit of a hollow body structure and act as a valve to control the flow of material
sphincters
What is an epidemiological study?
study of patterns, causes and effects of health and disease in populations.
dietary supplements must have
supplement facts panel on the label
how do you know a product is a dietary supplement?
taken by mouth in tablet, capsule, gel, powder or other NONFOOD form
two most important factors that influence food
taste and texture
Purpose of Dietary Guidelines for Americans
tool to help individuals consume healthy, nutritionally adequate diet.
· Describe the typical American diet.
typical american diet contains too much sodium, solid fat, saturated fat, and sugar and not enough fruits, vegetables, low-fat dairy, and whole-grain foods o American cuisine is truly a melting pot of cultural contributions to foods and tastes. Although Americans receive and believe many messages about the role of diet in good health, these beliefs do not always translate into better food choices
Digestive muscular actions-
under autonomic nervous system control
define undernutrition and overnutrition
undernutrition: poor health resulting from depletion of nutrients caused by inadequate nutrient intake over time. overnutrition: long-term consumption of an excess of nutrients.
• Water-soluble nutrients and small fat molecules are absorbed in
vascular system from small intestine and routed to the liver before being transported to the cells.
Fat-soluble nutrients, absorbed into lymph vessels (lymphatic system), initially bypass the liver to enter the
vascular system, and eventually are transported to liver for further metabolism
organic compounds necessary for reproduction, growth, and maintenance of the body
vitamins
what nutrient is the most important one?
water
simple chemical structures
water and minerals
list the six classes of nutrients
water, lipids(fats&oils), carbohydrates, protein, vitamins, and minerals
Dietary Supplements: Who
who: Over one-half of American adults use at least one form of dietary supplement
So, just what is CAM about?
• A broad range of healing philosophies, approaches and therapies that include treatments and health care practices not widely taught or practiced in mainstream medical care, not generally reimbursed by insurance carriers
Nutrition Assessment Methods how do you convert lbs to kilograms? convert inches to cm?
• Anthropometric Measurements • Biochemical Tests • Clinical Observations • Dietary Intake divide number of pounds by 2.2 inches x 2.54 cm = cm
Scientific Information can evolve into misinformation.
• As scientific information is made accessible to more and more people, less detail is provided and more opinion and sensationalism are introduced. • Sources include professional journals, scientific magazines, generalist magazines and newspapers, nightly news bites, and unattributed Internet sites.
"ABCDMV"- a closer look: —consuming the right proportion of foods. - Among food groups, energy sources, other nutrients - Energy eaten with energy used in daily activities and exercise
• Balance
"ABCDMV"- a closer look: —balancing the amount of foods and energy to sustain physical activities and metabolic needs. - To maintain, allow for growth or gain, or to lose weight - Focus on getting the most nutrients for your calories
• Calorie (energy) control
• Practices typically used in addition to conventional medicine
• Complementary
- Loose, watery, frequent stools - Symptom of diseases/infections - Can cause dehydration
• Diarrhea
Nutrition Assessment: Dietary Intake Analysis Methods
• Diet History • Food Record • Food Frequency Questionnaire • 24-Hour Recall • Methods of Evaluating Dietary Intake Data - Comparison to Dietary Standards - Comparison to DGA and DRIs
Overview of Absorption in the Small Intestine Foods have to be digested before they can be absorbed.
• Digestion breaks down food into nutrients, to allow absorption, which is the uptake of those nutrients from the GI tract (primarily small intestine), for transport into blood or lymph for utilization throughout the body.
- Pouches along colon - High-fiber diet reduces formation
• Diverticulosis
- 3 Sections of small intestine
• Duodenum, jejunum, ileum
Amount that meets the nutrient requirements of 50% of people in a life stage/gender group - Based on functional indicator of optimal health
• Estimated Average Requirement (EAR)
Dietary Supplements in the Marketplace • Regulations- Supplements differently regulated than drugs, freedom of speech & press prevail
• FTC: regulates advertising -Priority on health & safety at serious risk, and vulnerable-sick consumers • Dietary Supplement Health and Education Act • FDA: labeling, content - No premarket approval required - Supplemental facts panel - claims
The anatomy of the small intestine allows efficient absorption; what is it
• Folds, villi, microvilli expand absorptive surface • Fat-soluble nutrients go into lymph • Other nutrients go directly into blood
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 and moderation. • A combination of whole grains, vegetables, legumes, fruits, meats or meat alternates and milk products is essential to a healthy diet.
• Other Nutrition Experts
• Health and medical professionals with additional nutrition education
Supplement labels - Claims allowed
• Health claims (approved by FDA), structure/function claims, nutrient content claims - Examples » Calcium and osteoporosis » Folate and neural tube defects • Structure/function claims - Must have "disclaimer" statement on label • Nutrient content claims - Consistent with definitions approved for foods
- Backward flow of stomach contents into the esophagus. - Antacids and acid controllers may help indigestion. - Reduced by smaller meals, less fat, not lying down right after meals - Improved with weight loss
• Heartburn and Gastroesophageal Reflux
Herbal Supplements
• Herbal therapy (phytotherapy) is the therapeutic use of herbs and other plants to promote health and treat disease. • Most cultures have long traditions of herbal therapy • In many parts of world, people depend primarily on herbal therapy; modern medicines not available. • Herbs sold in mass markets are very different from uses in traditional practices • Little scientific evidence of efficacy, safety
benefits of phytochemicals
• High consumption of fruits/vegetables associated with decreased risk of chronic diseases • Benefits are as varied as the phytochemicals themselves. Many neutralize or reduce free radicals concentrations, which is protective against cancer and heart disease. • Selected examples and benefits from Table SF.4: • Phytoestrogens: some evidence suggests protective effects from moderate soy intake throughout life may lower risk of breast cancer • Carotenoids Lutein and xanthins pigments in plants are associated with lower incidence of age-related macular degeneration, • Flavonoids and Phenolic Acids- Antioxidant action • Plant Stanols/Sterols- may reduce CHD risk
Harmful herbs • Examples of herbs with known dangerous side effects
• Kava Chamomile • Ephedra Echinacea • Licorice Senna • St. Johns Wort Valerian • Gingko biloba
National Center for Complementary and Integrative Health (NCCIH) is part of the National Institutes of Health (NIH)
• Mission: "define through rigorous scientific investigation, the usefulness and safety of complementary and integrative health approaches and their roles in improving health and health care"
Digestion involves _______food with digestive juices, _______ it through the digestive tract, and ______________large molecules of food into smaller molecules. Digestion begins in the mouth, when you chew and swallow, and is completed in the colon.
• Mixing • Moving • Breaking down
is the state of having all nutrients available in amounts needed by the body for overall health.
• Nutritional health
The Gastrointestinal Tract
• Organization -Mouth -> anus Esophagus, stomach, small intestine, large intestine -Accessory organs Salivary glands, liver, pancreas, gallbladder • Functions - Ingestion - Transport - Secretion - Digestion - Absorption - Elimination Although digestion begins in the mouth, most digestion occurs in the stomach and small intestine. Absorption primarily takes place in the small intestine
Portion Distortion
• Perception that large portion sizes are appropriate • Contributes to positive energy balance, leading to weight gain over time and ultimately may result in obesity
Two Main Categories of Influences on our Food Choices
• Personal Preferences • Environmental Factors
Sorting facts and fallacies in the media
• Popular media may distort facts through omission of details. • In-depth research article becomes 30-second sound bite
Influences on Digestion and Absorption
• Psychological Influences • Chemical Influences • Bacterial Influences
Dietary Supplements: Natural Health Products: Herbs
• Relatively recent scientific trials showed some herbs may be helpful, but many have not been proven to have anticipated effects (Table SF.1) • Suggested benefits of many herbs based on long history of informal observation • More research needed about effects, safety and potential interactions with medicines and other natural products • Important Rule of Thumb: • Any herb strong enough to help you can be strong enough to hurt you • Can interfere with standard medicines • May have toxic side effects and be harmful in certain conditions • Before taking any supplements, it's a good idea to consult your health care practitioner
Publishing experimental results
• Scientists publish results of experiments in scientific journals to communicate new information • Peer review process reduces chance that low quality research is published
- Gastrin- secreted by stomach- does what
• Stimulates HCl, pepsinogen release, ↑ motility
BEGAN CHAPTER 3 What is Digestion?
• The process of breaking down foods into nutrients to prepare for absorption so the body can use them to build and nourish cells and to provide energy. • It turns food into fuel
Enterohepatic Circulation
• This is recycling process for bile- first produced by the liver and stored-released by the gallbladder into small intestine. • In the small intestine, bile assists with digestion. • Bile salts from bile are reabsorbed and sent back to the liver for reuse. • Fiber binds with bile and prevents some of its reabsorption and reuse. Non-absorbed bile is eliminated in feces.
Anatomy of Absorptive System in the Small Intestine
• Villi are the fingerlike projections within the folds of the small intestine that move in a wave-like pattern to trap nutrients. • Microvilli are the microscopic hairlike projections on each villi. • Crypts are the tubular glands that lie between the intestinal villi and secrete digestive enzymes. • Goblet cells are located between the villi and secrete a protective thick mucus.
START Spotlight on Dietary Supplements and Functional Foods: Dietary Supplements: What
• What: a product ingested orally in a non-food form (tablet, capsule, powder, liquid) that has one or more of: vitamins, minerals, amino acids, herbs, enzymes, metabolites or concentrates. • Wide variety of products claiming to improve almost anything you can think of... - From immune function, to memory, mood, strength, etc
- Secretin- secreted by the duodenum
• stimulates pancreatic juices release, opposite effects of gastrin • Pancreatic secretions change based on the content of the diet. • The pancreas is protected against enzymes by creating enzyme precursors called proenzymes or zymogen.
the beginning of the digestive system.
Mouth
Phytochemicals make foods
"functional" Complex chemicals that vary from plant to plant May promote good health in humans, but not essential like vitamins
the maximum levels of daily nutrient intakes that are unlikely to pose health risk to almost all of the individuals in the group for whom they are designed
(UL) Tolerable Upper Intake Levels
publishing research
- A peer review process is used to evaluate the procedures used and the conclusions drawn from a study. - When a study has validity it means that the conclusions were supported by the findings. - Replication is used to confirm or disprove findings.
CHAPTER TWO START Linking Nutrients, Foods, and Health; Planning How You Will Eat
- Adequacy - Balance - Calorie Control - Nutrient Density - Moderation - Variety = ABCDMV
Ingredients List and Basic Information
- All ingredients listed - Descending order of predominance by weight - Statement of identity - Net contents of the package - Name and address of manufacturer, packer, distributor
Dietary Reference Intakes (DRIs) • Framework of dietary standards to provide not only adequate intakes, but also provide optimal nutrition
- Apply to healthy people - Recommendations are not minimum requirements and can be adjusted for individuals by registered dietitians. - Achieved by consuming a variety of foods - Apply to average daily intakes - Each DRI category serves a unique purpose: Estimated Average Requirement (EAR) Recommended Dietary Allowance (RDA) Adequate Intake (AI) Tolerable Upper Intake Level (UL)
Nutrition in the News
- Can be misleading and contradictory - May report scientific findings prematurely
vegetables? what are legumes? Lentils?
- Choose fresh vegetables often. - Dark green leafy and yellow-orange vegetables are important. - Good sources of vitamins, minerals, and fiber - Be careful about added fat and salt. - Legumes • Economical • Nutrient-dense • Low-fat, good sources of protein and fiber LEGUMES: Any of thousands of plant species that have seed pods that split along both sides when ripe. More commonly consumed legumes: BEANS, LENTILS, PEANUTS, PEAS and SOYBEANS. Others, such as clover and alfalfa, may be used as animal fodder. When the seeds of a legume are dried, they're referred to as PULSES. The high-protein legumes are a staple throughout the world. They also contain some vitamin B, carbohydrates, fats and minerals LENTILS: Lens-shaped pulses that grow on an annual, bushlike plant. They have a short cooking time and a distinctive earthy flavor. A variety of lentils exist with colors that range from yellow to red-orange to green, brown or even black. There are both large and small-seeded varieties. Lentils are generally sold as dry seeds (pulses)
• Identifying Nutrition Experts
- Consumers listen to many unqualified advisors/ "experts"about nutrition - Evaluate credentials. - Legitimate nutrition experts • The Registered Dietitian (RD) • Graduates of accredited programs, maintain up-to-date registration • May use the title nutritionist, look for RD credential • Many states require license to practice- licensed dietitians (LD). • Certified nutritionists, certified nutritional consultants, and certified nutritional therapists don't have the same credentials as an RD. • Government-funded agencies utilize public-health RDs
Conducting Research
- Controls • Subjects are divided into two groups. The experimental group receives the treatment being studied and the control group does not receive the treatment. • Randomization is used to randomly assign subjects to the experimental or control group. - Sample sizes must be large to accurately detect differences. - Placebos are used to control the placebo effect with subjects in experiments. Subjects in blind experiments do not know if they are in the experimental or control group. - In double-blind experiments, the researchers and the subjects do not know their groups to prevent researcher bias.
Analyzing Research Findings
- Correlations and causes in experiments involve studying variables and correlations, or relationships, between variables. • A positive correlation is when the same thing happens to two variables: as one increases the other increases. • A negative correlation if when the opposite things happen to two variables: as one increases the other decreases. - Cautious conclusions must be drawn when examining or generalizing the results of any single study.
Milk and diary
- Dairy foods are often fortified with vitamins A and D. - Imitation foods that resemble other foods are usually nutritionally inferior. - Food substitutes are designed to replace other foods. - Many lower fat dairy products are available including fat-free, low-fat, non-fat, skim, no-fat, reduced-fat products.
• Large intestine
- Digestion • Nutrient digestion already complete • Some digestion of fiber by bacteria - Absorption • Water • Sodium, potassium, chloride, vitamin b12• Vitamin K (produced by bacteria) - Elimination • Of undigested residue, including some fibers as stool
MyPlate is designed to convey 7 high-priority key messages:
- Enjoy food, but eat less. - Avoid oversized portions. - Make half your plate fruits and vegetables. - Drink water instead of sugary drinks. - Switch to fat-free or low-fat (1%) milk and dairy products. - Compare sodium in foods. - Make at least half your grains whole grains.
Chemical Breakdown
- Enzymes - Other secretions
• Scientific process Types of studies
- Epidemiological - Animal - Cell culture - Human = • Case control • Clinical trial
• The Continuum of Nutritional Status
- Extremes of undernutrition and overnutrition - Region of good health between these
vitamins fat-soluble ones? (4) water-soluble ones? (2)
- Fat-soluble: A, D, E, K - Water-soluble: B vitamins, vitamin C - Functions • Regulation - Food sources • All food group
Secretions of Digestion • Include digestive enzymes that act as catalysts in hydrolysis reactions
- Saliva from salivary glands moistens foods, initiates carbohydrate digestion. - Gastric juice from gastric glands includes hydrochloric acid. The goblet cells in stomach wall secrete mucus to protect the walls of stomach from high acidity levels that are measured by pH units. - Pancreatic juice contains 3 enzymes (amylase, lipase, protease) and bicarbonate. - Bile is produced by liver, stored in gall bladder and acts as emulsifier to suspend fat to allow action by digestive enzymes. - Intestinal secretions: also contain 3 types of enzymes for carbohydrate, protein and fat digestion.
• Pancreas
- Secretes bicarbonate - Secretes digestive enzymes
• Liver
- Secretes bile - Detoxificaton & metabolic transformations, storage center
• Gallbladder
- Stores and releases bile
Carbohydrates
- Sugars and starches - Functions • Energy source - Food sources • Grains • Vegetables • Fruits • Dairy products
lipids
- Triglycerides (fats and oils), cholesterol, and phospholipids - Functions • Energy source, structure, regulation - Food sources • Fats and oils • Meats • Dairy products
What does it mean to be healthy?
- WHO defines health as "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity."
benefits of phytochemicals
-Anticancer Activity -Prevent Chronic Disease -Neutralize free radicals
phytochemicals
-In plants, they are beneficial and protective - Phytochemical composition of fruits and vegetables important part of why Dietary Guidelines recommend daily
protein
-Made of amino acids - Functions • Energy source, structure, regulation - Food sources • Meats • Dairy products • Legumes, vegetables, grains
General functions of nutrients
-Supply energy • Carbohydrates, lipids, and proteins - Contribute to cell and body structure - Regulate body processes
• Intestinal cells have specialized structure to absorb different nutrients into different systems for transport throughout the body. • Two Transport Systems =
-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.
describe types of claims that might be found on food labels
-nutrition content claims: regulated by NLEA and FDA lets them put terms like low in fat, high in fiber -health claims: statement that associates food or substance in food with a disease or health-related condition -structure/function claim describe potential effects on body structures or functions example: calcium helps build strong bones
five mandatory components found on all food labels
-statement of identity/name of food -net weight of food inside package;not including weight of package -name and address of manufacturer, packer, or distributor -list of ingredients in descending order by weight -nutrition information
Sight, smell, taste, sound, and thought of food...
...give a kick start to the digestive processes through cephalic phase responses.
Dietary Guidelines for Americans (DGA): Five overarching concepts:
1. Follow a healthy eating pattern across the lifespan. 2. Focus on variety, nutrient density, and amount. 3. Limit calories from added sugars and saturated fats and reduce sodium intake 4. Shift to healthier food and beverage choices. 5. Support healthy eating patterns for all.
Energy for protein
4 kcal/g
How many kcals per gram of alcohol?
7kcal/g
• More than __% of ingested nutrients are absorbed in small intestine due to its specialized structure and function.
90%
Describe the path food follows as it travels through the digestive system.
Mouth, esophagus, stomach, small intestine, large intestine, and rectum
What are some of the possible complications involved in using herbal medicines?
Because herbal supplements do not have to be approved prior to sale, their safety and efficacy has not been scrutinized by the FDA. Herbal medicines have the potential to interact with drugs and with nutrients. Such interactions could affect the strength of medications and the use of nutrients in the body. In addition, because herbal medicines are not regulated as drugs, there are no standards for purity. This leaves open the possibility that contaminants in the product could cause harmful effects.
How many kCals are in 1 gram of carbohydrates, protein and of fat?
Carb- 4kcal/g Protein-4kcal/g Fats-9kcal/g
Digestion of Pizza
Carbohydrate in Crust and tomato sauce: Enzymes in mouth begin starch breakdown, temporarily stopped in stomach. In small intestine, enzymes break down starch, and sugar end products are absorbed into the blood. Fat in Cheese and Pepperoni: Stomach absorbs a few short-chain F.A., but most of fat is broken down and absorbed in the small intestine , where it is absorbed into lymphatic system. Protein in Cheese, Pepperoni and Crust: Stomach acid unfolds proteins and enzymes begin breakdown. Small intestine completes the process, with end product of amino acids, absorbed by vascular system for transport to liver and rest of the body.
Hard, dry, infrequent stools - Improved by high fiber/ fluid intake, exercise
Constipation -
• Define Dietary Standards. -Who develops them?
Definition: Sets of recommended intake values for individual nutrients U.S.A.: Food and Nutrition Board of National Academy of Sciences
Foundation of federal nutrition policy; developed by the US Dept Agriculture (USDA) and Dept Health and Human Services (DHHS)
Dietary Guidelines for Americans (DGA)
Provide a road map with simple and clear statements about food choices to help Americans make informed food and activity decisions.
Dietary Guidelines for Americans (DGA)
Science-based guidelines intended to improved overall health, first released in 1980, revised every 5 years
Dietary Guidelines for Americans (DGA)
• Provide evidence-based recommendations about the components of a healthy and nutritionally adequate diet • Focus on disease prevention rather than disease treatment • Inform Federal food, nutrition, and health policies and programs
Dietary Guidelines for Americans (DGA)
small intestine
Digestive Secretions • Bicarbonate (from pancreas) neutralizes stomach acid • Pancreatic & intestinal enzymes digest: - Carbohydrates - Fat - Protein
list and define 4 main dietary reference intake categories (DRIs)
EAR - Estimated average requirement; nutrient intake level estimated to meet the needs of 50% of individuals in a life RDA - recommended dietary allowance; nutrient intake level that is sufficient to meed the needs of 97-98% of individuals AI - adequate intake; nutrient intake that appears to sustain a defined nutritional state UL - Tolerable Upper Intake level; maximum level of daily nutrient intake that poses little risk of adverse health effects
the intake value that meets the estimated nutrient needs of 50% of individuals in a specific life-stage and gender group
EAR- estimated average requirement
dietary energy intake that is predicted to maintain energy balance in a healthy adult of a defined age, gender, weight, height, and level of physical activity consistent with good health
EER- estimated energy requirement
represents the average daily energy intake to maintain energy balance and good health for population groups
Estimated Energy Requirement (EER)
Natural Health Products and Herbal Therapies in Complementary and Alternative Medicine (CAM)
Herbal therapies are considered a type of "Natural Products" used in Complementary and Alternative Medicine (CAM) • Some consumers will: • Seek alternative medicine to replace conventional therapies because it is more in line with their beliefs about health and life. • Use alternative therapies in addition to conventional therapies.
GI tract has several layers, including:
Mucosa Submucosa Circular muscle Longitudinal muscle Serosa
Fluid that travels through the lymphatic system, made up of large fat particles and fluid drained from the areas between cells, is called _____.
lymph
• The incomplete digestion of lactose in milk due to low levels of the intestinal enzyme lactase. It results in symptoms (from mild to severe) of bloating, gas, abdominal pain and diarrhea.
Lactose Intolerance • Almost all infants are born with adequate lactase to have normal digestion of breast milk or formula. In affected racial/ethnic groups, lactase activity is greatly decreased after weaning. • Of all the world's populations, Native Americans have the highest level of lactose intolerance, with 100 percent intolerance. • Ninety-eight percent of Southeast Asians are intolerant, while only 2 percent of the Swedish population are intolerant.
What determines whether a mineral is a macro mineral or a micro-(trace) mineral?
Macro= the body needs large quantities of and so they are major minerals required in the diet Micro= because our body needs small amounts of. Required in small amounts of diet
food over-consumed by americans on average
Meat, eggs, nuts, grains, added sugars, and solid fats
Dietary Supplements: How Much?
Megadoses in Conventional medicine • Drug interactions • Malabsorption syndromes • Treatment of deficiencies • Pharmacologic (drug-like) effects • Orthomolecular nutrition (??) • Proposed for disease prevention • Megadose Risks: Can act as a drug, create deficits of other nutrients, interfere with absorption of others
"ABCDMV"- a closer look: providing enough but not too much of a food or nutrient - Low nutrient dense and empty calorie foods don't have to be eliminated, the key is occasional or less-frequent inclusion - Can too much of a good thing apply to vitamins, minerals, as well as any food??
Moderation (dietary)
"ABCDMV"- a closer look: —measuring nutrient content of a food relative to its energy content. - Nutrient-dense foods have substantial amounts of vitamins and minerals and relatively few calories per serving - Empty-kcalorie foods contribute energy but lack significant amounts of any nutrients.
Nutrient Density
How do our health beliefs affect our food choices?
Our perception that a specific food can prevent or delay an onset of disease can have a powerful influence on our diet and food choices.
what is the purpose of the % daily value listed next to most nutrients on food labels?
Percent Daily Value (DV) on the Nutrition Facts label is a guide to the nutrients in one serving of food. For example, if the label lists 15% for calcium, it means that one serving provides 15% of the calcium you need each day. DVs are based on a 2,000-calorie diet for healthy adults. Even if your diet is higher or lower in calories, you can still use the DV as a guide. For example, it tells you whether a food is high or low in a specific nutrient, defined as follows: Low: 5% or less of a nutrient High: 20% or more of a nutrient
physical breakdown. wavelike, rhythmic muscular contractions of the GI tract that propel the contents down the tract = _________ periodic muscle contractions at intervals along the GI tract that alternate forward and backward movements of contents, thereby breaking apart chunks of the food mass and mixing in digestive juices = _________.
Peristalsis Segmentation
What is a placebo?
Placebo is the inactive substance that is compared to the active substance in a study/experiment.
the nutrient intake levels that meet the nutrient needs of almost all (97-98%) individuals in a life-stage and gender group
RDA-recommended dietary allowance
Amount that meets the needs of most people in a life stage/gender group
Recommended Dietary Allowance (RDA)
8 Red Flags of Nutritional Quackery and Junk Science - One or more of these is a warning sign of nutrition misinformation: o 10 red flags of junk science
Satisfaction guaranteed • Quick and easy fixes • Natural • One product does all • Time tested • Paranoid accusations • Personal testimonials • Meaningless medical jargon § Recommendations that promise a quick fix § Dire warnings of danger from a single product or regimen § Claims that sound too good to be true § Simplistic conclusions drawn from a complex study § Recommendations based on a single study § Statements refuted by reputable scientific organizations § list of "good" and "bad" foods § recommendations made to help sell a product § recommendations based on studies that were not peer reviewed § recommendations from studies that ignore differences among individuals or groups
= muscular valves which control passage of food where one organ connects with anothe
Sphincters
Mouth: the beginning of the digestive system. Digestion processes here:
Stimulation of taste buds - Mastication (chewing) Swallowing- the epiglottis closes to prevent food from entering the pharynx. After swallowing, the food mass is called a bolus . Secretions: Enzymes: Salivary amylase acts on starch, Lingual lipase acts on fat Saliva: Moistens food for swallowing
What are Phytochemicals? Example?
Substances in plants that may possess health protective effects, even if they are not essential for life. Example: Antioxidant: reduce the risk for heart disease and cancer.Example: Fiber:
Name 3 sensory aspects of food that influence our food choice.
Taste, Texture & Smell
What organs make up the digestive system?
Teeth/tongue, salivary glands, pharynx, esophagus, stomach, small intestine, large intestine (colon), rectum, liver, gall bladder, pancreas
Just under the serosal layer of the GI tract, are layers of _______________ and _____________that help with physical breakdown of food and move it along the tract.
longitudinal muscle circular muscle
Name three "assisting" organs that are not part of the GI tract but that are needed for proper digestion. What are their roles in digestion?
The salivary glands produce saliva that moistens food, lubricating it for easy swallowing. Saliva contains enzymes that begin the process of chemical digestion. The liver produces and secretes bile, which emulsifies fats in the small intestine, thus aiding fat digestion. The gallbladder stores and releases bile from the liver. The pancreas secretes digestive enzymes that help digest nutrients. also secretes bicarbonates
gastrointestinal tract
The stomach and intestine as a functional unit.
Dietary Supplements: Who Needs Them?
Those with increased nutrient needs and/or inadequate intake Infants: iron and fluoride Women of childbearing age:folate Pregnant and breastfeeding women: folate, iron Elderly: Vit B12,Vit D, Calcium People with severe food restrictions Low energy intake, allergies Strict vegetarian/vegan (no animal foods or dairy): Vit B12 Vit D, Ca, Zn, Fe
cavity or hollow channel in any organ or structure of the body
lumen
maximum level of daily nutrient intake that poses little risk of adverse health effects to almost all individuals Intake above the UL can be harmful
Tolerable Upper Intake Level (UL)
government agency that monitors production of eggs, poultry, and meat
U.S. department of Ag
"ABCDMV"- a closer look: eating a wide selection of foods within and among the major food groups - Ensures meeting nutrient needs
Variety (dietary)
food under-consumed by americans on average
Vegetables, dairy, fruit, whole grains
one of a family of plant chemicals, the carotenoids. Other in this big family include alpha-carotene and beta-carotene
lycopene
Dietary Supplements: Why
Why: Most common reasons- to improve or maintain health, but <25% taken due to health care provider recommendation • Health care practitioners often recommend moderate levels of nutrient supplements for persons- - having elevated nutrient needs - who may not eat a well-balanced diet
collective experience that describes taste and smell
flavor
Taste and Smell: The Beginnings of Our Food Experience The Chemosenses - Olfactory cells - Gustatory cells - Common chemical sense - All contribute to our perception of _______. - Also contribute to __________________
flavor cephalic phase responses = are innate and learned physiological responses to sensory signals that prepare the gastrointestinal tract for the optimal processing of ingested foods
A mixture of chemicals
food
preferred mode of getting nutrition is through
food
refers to the addition of vitamins or minerals that were not originally present in a food
fortify
A food that may provide a health benefit beyond basic nutrition is known as a
functional food
A food or food component that provides health benefits beyond basic or expected nutrition value =
functional foods A few examples of functional food components from Table SF.4: Probiotics Prebiotics Omega-3 Fatty Acids Soy Protein Phytochemicals Dietary Fiber Foods can also be enhanced with functional ingredients like orange juice fortified with calcium and yogurt fortified with live active bacteria cultures. The added components are considered food additives.
an enzyme in the stomach that hydrolyzes certain triglycerides into fatty acids and glycerol
gastric lipase
a polypeptide hormone released from the walls of the stomach mucosa and duodenum that stimulates gastric secretions and motility
gastrin
Energy for Carbohydrates
grams given x 4 kcal/grams
Energy for fats
grams given x 9kcal/g
• The principle of _________ is important in the functioning of the digestive and absorptive systems. The body's hormonal and nervous control systems keep conditions normal.
homeostasis
the sphincter at the junction of the small intestine and large intestine
ileocecal valve
a comprehensive, often interdisciplinary approach to treatment, prevention, and health promotion that bring together complementary and conventional therapies
integrative health care
a glycoprotein released from parietal cells in the stomach wall that binds and aids in absorption of vitamin B12
intrinsic factor
Micro minerals
iron, iodine, manganese, copper, cobalt, zinc, molybdenum, selenium, chromium
plant chemicals that include genistein and daidzein and may have positive effects against cancer and heart disease
isoflavones
Besides ingested water, the entire GI tract produces a large volume of fluids, about 4-5 liters daily, and 85% of total water is absorbed in the
jejunum.
energy in foods is measured in
kilocalories
a small lymphatic vessel in the interior of each intestinal villus that picks up chylomicrons and fat-soluble vitamins from intestinal cells
lacteal
- Ileocecal valve controls chyme flow - Absorption and Elimination =
large intestine
electrolytes and water are absorbed from the
large intestine
a family of plants with edible seed pods, such as peas, beans, lentils, and soybeans
legumes
a fat-splitting enzyme secreted by cells at the base of the tongue
lingual lipase
complex chemical structures
lipids, carbohydrates, vitamins, proteins
muscle fibers aligned lengthwise
longitudinal muscle
