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Chapter 03
The Human Body: A
Nutrition Perspective
Wardlaw’s Contemporary
Nutrition: A Functional
Approach
Seventh Edition
Anne M. Smith, Angela L. Collene,
Colleen K. Spees
© McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.
Section 3.1 Concepts: Cells, Tissues, and Organs
1. Choose three organelles and explain their relevance to
human nutrition.
2. List the four types of tissues and give an example of
where you could find each in the body.
3. Examine Figure 3-3. Provide three examples of ways the
organs of one system support the functions of another
system.
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Cells
• Cells are basic structural and functional components of
life.
• Your body has trillions of them!
• They are specialized to perform particular functions.
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Figure 3-1: Animal Cell
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Cell (Plasma) Membrane
• Each cell is separated by cell membrane.
• Also called plasma membrane.
• Holds cellular contents together.
• Regulates flow of substances in and out of cell.
• Cholesterol is a component of each cell membrane.
• Protein structures act as transport vehicles and function as
enzymes that facilitate chemical processes.
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Figure 3-2: Cell Membrane
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Cell: Cytoplasm
• A combination of fluid material and organelles within the
cell, not including the nucleus.
• Energy for use by the cell can be produced by chemical
processes that occur in the cytoplasm.
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Cell: Mitochondria and Cell Nucleus
Mitochondria
• Where energy-yielding nutrients (carbohydrate, protein,
and fat) from food are converted into energy that cells can
use.
Cell Nucleus
• Contains genetic material responsible for controlling
actions that occur in cell.
• Chromosomes
• Genes made up of deoxyribonucleic acid (DNA)
• “Messenger” molecule called ribonucleic acid (RNA)
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Cell: Endoplasmic Reticulum (ER) and Golgi Complex
Endoplasmic Reticulum (ER)
• Organelle composed of a network of canals running
through the cytoplasm.
• Part of the endoplasmic reticulum contains ribosomes.
• Involved in lipid synthesis, detoxification of toxic
substances, and calcium storage release in the cell
Golgi Complex
• Cell organelle near the nucleus that processes newly
synthesized protein for secretion or distribution to other
organelles.
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Cell: Lysosomes and Peroxisomes
Lysosomes
• Contain digestive enzymes for use inside the cell for
turnover of cell parts
• Digest worn-out or damaged cell components
Peroxisomes
• Destroy toxic products within cell
• Contain enzymes that detoxify harmful chemicals
• Contain a protective enzyme called catalase
• Prevent excessive accumulation of hydrogen peroxide in
cell
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Tissues
Epithelial tissue: composed of cells that cover surfaces
both inside and outside the body.
• Epithelial cells make up the lining of the respiratory tract.
• Secrete important substances, absorb nutrients, and
excrete waste
Connective tissue: supports and protects the body, stores
fat, and produces blood cells.
Muscle tissue: designed for movement.
Nervous tissue: found in brain and spinal cord; designed for
communication.
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Organs
• Organ: combination of one or more types of tissue to form
more complex structures.
• Organ system: several organs that work together, such
as the digestive system.
• All organs contribute to nutritional health, and a person’s
overall nutritional state determines how well each organ
functions.
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Figure 3-3: Organ Systems of the Body:
Cardiovascular System
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Figure 3-3: Organ Systems of the Body:
Lymphatic and Immune Systems
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Figure 3-3: Organ Systems of the Body:
Urinary System
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Figure 3-3: Organ Systems of the Body:
Nervous System
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Figure 3-3: Organ Systems of the Body:
Endocrine System
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Figure 3-3: Organ Systems of the Body:
Digestive System
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Figure 3-3: Organ Systems of the Body:
Integumentary System
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Figure 3-3: Organ Systems of the Body:
Skeletal System
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Figure 3-3: Organ Systems of the Body:
Muscular System
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Figure 3-3: Organ Systems of the Body:
Respiratory System
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Figure 3-3: Organ Systems of the Body:
Reproductive System
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Section 3.2 Concepts: Metabolism Is the Chemistry of
Life
1. What are the differences between anabolic and catabolic
reactions?
2. What is the purpose of ATP?
3. Describe three ways essential nutrients support cell
functions.
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Cell Metabolism
Metabolism: entire collection of chemical processes involved in
maintaining life.
• Biochemical reactions take place in the cell cytoplasm and
organelles.
• Anabolic metabolism requires energy.
• Catabolic metabolism takes molecules apart and releases
energy.
• Catabolism of carbohydrates, proteins, and fats yields energy.
• Energy production begins in cytoplasm.
• Remaining aerobic steps take place in mitochondria.
• Energy is harnessed in the high-energy compound adenosine
triphosphate (ATP).
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Section 3.3 Concepts: Cardiovascular System and
Lymphatic System
1. Describe how nutrients, oxygen, and wastes are
exchanged between the body’s internal and external
environments.
2. What is hepatic portal circulation?
3. Which nutrients are absorbed into the lymph?
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Cardiovascular System 1
Heart: muscular pump
• Contracts and relaxes 50 to 90 times per minute when
body is at rest.
Blood:
• Composed of plasma, red blood cells, white blood cells,
platelets, and other substances.
Blood Flow: two routes
• Blood circulates from right side of heart, through lungs,
picks up oxygen, and releases carbon dioxide.
• Oxygenated blood returns to left side of the heart.
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Figure 3-4: Cardiovascular System
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Cardiovascular System 2
• Arteries: Blood leaves the heart via arteries.
• Capillaries: Arteries branch into capillaries, a network of
tiny blood vessels that are just one cell layer thick.
Exchange of nutrients, oxygen, and waste products
between the blood and cells occurs through the tiny, web
like pores of the capillaries.
• Veins: Blood returns to the heart via the veins.
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Cardiovascular System 3
• Facilitates exchange of oxygen, nutrients, and wastes
between the body’s internal and external environments;
• Delivers hormones to their target cells;
• Maintains constant body temperature; and
• Distributes white blood cells throughout body to protect
against pathogens as part of immune system.
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Lymphatic System
Network of vessels and fluid (lymph)
• Accepts fluid surrounding cells and large particles such as
products of fat absorption.
• Lymph is a
• clear fluid that eventually passes into bloodstream from the
lymphatic system.
• also contains white blood cells, which support immune function.
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Figure 3-5: Capillary and Lymph Vessels
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Circulation in the Gastrointestinal Tract
Portal circulation
• Most water-soluble nutrients from recently eaten foods are
transferred into the hepatic portal circulation.
• Nutrients pass from intestinal capillaries into veins that merge
into large hepatic portal vein that leads directly to liver.
• Enables liver to process absorbed nutrients before they enter
the general circulation.
Lymphatic circulation
• Most dietary fats are too large to enter capillaries.
• Most dietary fats enter lacteals and travel through the
lymphatic system until lymph is emptied into the bloodstream by
a duct near the heart.
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Section 3.4 Concepts: Urinary System
1. List three functions of the kidneys.
2. Trace the path of waste products out of the body.
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Urinary System 1
• Kidneys: two, on each side of spinal column.
• Ureter: kidney connected to bladder by ureter.
• Urethra: bladder emptied by way of urethra.
• Urine: composed of water, dissolved waste products of
metabolism (for example, urea), and excess or unneeded
water-soluble vitamins and various minerals.
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Figure 3-6: Organs of the Urinary System
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Urinary System 2
Main Function: remove waste from body by constantly filtering
blood to control its composition.
• Tied to strength of cardiovascular system’s ability to maintain
adequate blood pressure and consumption of sufficient fluid.
• Some phytochemicals in cranberries may protect health of
urinary system.
Other Functions:
• Maintain acid–base balance (pH) of blood.
• Contribute to bone health by converting vitamin D into its active
hormone form.
• Produce a hormone that stimulates red blood cell synthesis.
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Section 3.5 Concepts: Nervous System
1. Why are sodium and potassium important for the work of
the nervous system?
2. How are signals transmitted between one neuron and the
next? Why are amino acids important in this process?
3. Which nutrient is the brain’s preferred source of energy?
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Nervous System
Brain, spinal cord, nerves, sensory receptors
Neuron: basic structural and functional unit
• Elongated, highly branched cells
• 100 billion neurons in body
• Respond to electrical and chemical signals
• Conduct electrical impulses
• Release chemical regulators
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Nerve Transmission
Transmission of signal in neuron occurs through change in
concentration of two nutrients: sodium and potassium.
As message is sent, there is an influx of sodium into neurons
and loss of potassium.
Concentrations of minerals
• Restored to normal amounts in neuron after signal passes.
• Ready to conduct another message.
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Figure 3-7: Neuron: Nerve Impulses
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Nutrient Needs of Brain
Neurotransmitters:
• When signal must bridge a gap (synapse), electrical
message is converted into a chemical signal—
neurotransmitter.
• Made from amino acids
• Tryptophan used to make serotonin, involved in regulation of
mood, sleep, and other body functions.
• Tyrosine used to make norepinephrine and epinephrine (also
called adrenaline), involved in response to stress.
Glucose is the preferred fuel for the brain.
Lipids, protein, and vitamin B-12 support myelin sheath
covering nerve fibers.
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Section 3.6 Concepts: Endocrine System
1. What are the endocrine roles of the pancreas? What are
the exocrine roles of the pancreas?
2. What effect does insulin have on the storage of nutrients?
3. List at least three hormones that tend to increase blood
sugar.
4. If a person has hypothyroidism, the thyroid gland
produces low levels of thyroid hormone. Explain why a
person with hypothyroidism will tend to either lose weight
or gain weight.
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Endocrine System
Major role in regulation of metabolism, reproduction, water
balance, and many other functions.
• Endocrine glands: produce hormones
• Hormones:
• Chemical messengers
• Taken up by cells with correct receptor protein
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Figure 3-8: Action of Hormones
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Hormones
Insulin
• Produced by the pancreas.
• Insulin increases synthesis of glycogen in liver and
movement of glucose from bloodstream into body cells.
Thyroid hormones
• Produced by the thyroid gland to control metabolic rate.
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Figure 3-9: Pancreas
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Section 3.7 Concepts: Immune System
1. Contrast nonspecific (innate) and specific (adaptive)
immunity.
2. What are the roles of antigens and antibodies in the
immune response?
3. List three nutrients that support the immune system.
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Immune System
Skin and intestinal cells: work in concert with cells and
tissues of immune system to defend body against infection.
Nonspecific (innate) immunity: defenses that stop invasion
of pathogens, requires no previous encounter with pathogen.
• Engulfing microorganisms by phagocytosis
Specific (adaptive) immunity: function of white blood cells
directed at specific antigens.
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Role of Antibodies and Antigens
Antibody
• Blood protein binds foreign proteins found in body.
• Also called immunoglobulin
Antigen
• A substance that induces state of sensitivity and/or
resistance to microorganisms and toxic substances after a
lag period.
• Foreign substance that stimulates a specific aspect of the
immune system.
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Section 3.8 Concepts: Digestive System
1. Choose three secretions of the digestive system. Where is
each secreted? What is the role of each in the process of
digestion?
2. What are enzymes? Is bile an enzyme?
3. How do mucus and surface area affect absorption?
4. Which absorptive processes use energy? How does
concentration gradient factor into this?
5. What did you have for lunch today? Trace the path of your
meal through the digestive system. Where is each
macronutrient broken down as it passes through the GI
tract? Where is each absorbed?
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Digestive System 1
• Consists of gastrointestinal tract, accessory structures liver,
gallbladder, and pancreas.
• Performs mechanical and chemical processes of digestion,
absorption of nutrients, and elimination of wastes.
• Most processes of digestion and absorption are under
autonomic control.
• Digestion and absorption are controlled by signals from
nervous system and hormones from endocrine system.
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Digestive System 2
• Digestion: Large ingested molecules are mechanically and
chemically broken down, to produce basic nutrients that can
be absorbed across the wall of the GI tract.
• Absorption: Substances are taken up from GI tract and
enter bloodstream or lymph.
• Gastrointestinal (GI) tract: sites in the body for digestion
and absorption of nutrients; consists of mouth, esophagus,
stomach, small intestine, large intestine, rectum, and anus.
• Lumen: hollow opening inside a tube, such as GI tract
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Figure 3-10: Physiology of the GI Tract
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Figure 3-11: Enzyme Action
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Table 3-1: Secretions of the Digestive Tract 1
Secretion
Site of Production
Purpose
Saliva
Mouth
Contains enzymes that make a minor
contribution to starch and fat digestion
Blank
Blank
Lubrication of food for swallowing
Mucus
Mouth, esophagus, stomach, Protects GI tract cells
small intestine, large intestine
Blank
Blank
Lubricates food as it travels through
the GI tract
Enzymes
Mouth, stomach, small
intestine, pancreas
Promote digestion of carbohydrates,
fats, and proteins into forms small
enough for absorption (for example,
amylases, lipases, proteases)
Acid
Stomach
Promotes digestion of protein
Blank
Blank
Destroys pathogens
Blank
Blank
Solubilizes some minerals
Blank
Blank
Activates some enzymes
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Table 3-1: Secretions of the Digestive Tract 2
Secretion
Site of Production
Purpose
Bile
Liver (stored in
gallbladder)
Aids fat digestion in the small intestine
by suspending fat in water using bile
acids, cholesterol, and phospholipids
Bicarbonate
Pancreas, small
intestine
Neutralizes stomach acid when it
reaches the small intestine
Hormones
Stomach, small
intestine, pancreas
Stimulate production and/or release of
acid, enzymes, bile, and bicarbonate
Blank
Blank
Regulate movement of food matter
through the GI tract
Intrinsic factor
Stomach
Facilitates absorption of vitamin B-12
in the small intestine
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Mouth
Chews food to reduce it to smaller particles.
Taste buds on the tongue sense taste of foods.
• Sweet, sour, salty, bitter, umami, and oleogustus.
• Umami: brothy, meaty, savory flavor in some foods
• Oleogustus: flavor of fat
Sense of smell greatly contributes to ability to sense taste.
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Constituents of Saliva
Saliva: watery fluid produced by salivary glands in mouth.
• Contains lubricants, enzymes, and other substances.
Amylase: starch-digesting enzyme produced by salivary
glands and pancreas.
Lipase: fat-digesting enzyme produced by salivary glands,
stomach, and pancreas.
Mucus: thick fluid secreted by many cells throughout the body.
• Acts as lubricant and means of protection for cells.
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Components of Upper GI Tract 1
• Esophagus: tube in GI tract that connects pharynx with
stomach
• Pharynx: organ of digestive tract and respiratory tract at
back of oral and nasal cavities
• Trachea: airway from throat to lungs
• Epiglottis: flap that folds down over trachea during
swallowing
• Bolus: mixed with saliva, food mass swallowed from oral
cavity into pharynx
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Figure 3-12: Process of Swallowing
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Figure 3-13: Peristalsis
• Peristalsis:
coordinated muscular
contractions to propel
food down
gastrointestinal tract.
• The moving food
mass triggers a ring
of contraction in the
next region, which
pushes the food mass
even farther along.
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Components of Upper GI Tract 2
Lower esophageal sphincter: Circular muscle constricts
opening of esophagus to stomach
• Also called the gastroesophageal sphincter or the cardiac
sphincter
Chyme: mixture of stomach secretions and partially digested
food
Pyloric sphincter: ring of smooth muscle between stomach
and small intestine
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Figure 3-14: Physiology of the Stomach
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Stomach, Upper GI
• Large sac that can hold up to 4 cups for several hours.
• Size varies individually and can be altered by surgery.
• Concentration of stomach acid (hydrochloric acid) increases
as food enters.
• Chyme leaves stomach 1 teaspoon at a time and enters
small intestine through the pyloric sphincter.
• Very little absorption of nutrients occurs in stomach.
• Intrinsic factor is a protein-like compound produced by
stomach, enhances vitamin B-12 absorption.
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Gastric Secretions
Gastric juice: water, hydrochloric acid (HCl), enzymes
• Acid:
• Destroys activity of protein
• Activates digestive enzymes
• Partially digests dietary protein
• Makes dietary minerals (for example, calcium) soluble to improve
absorption.
• Mucus: Thick layer protects stomach from acid.
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Small Intestine 1
Duodenum: First segment
• Approximately 10 in. in length
• Receives chyme from stomach and digestive juices from
pancreas and gallbladder
• Site of most chemical digestion of nutrients
Jejunum: Middle segment
• Approximately 4 ft in length
Ileum: Last segment
• Approximately 5 ft in length
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Small Intestine 2
Villi: fingerlike protrusions that participate in digestion and
absorption of food.
Absorptive cells: also known as enterocytes; intestinal cells
that line villi and participate in nutrient absorption.
Microvilli: extensive folds on the mucosal surface of the
absorptive cells.
Combined folds, villi, and microvilli increase its surface area
600 times.
New intestinal absorptive cells are constantly produced in
crypts of small intestine.
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Figure 3-15: Organization of Small Intestine
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Nutrient Absorption
• Passive diffusion: diffusion of nutrients across absorptive
cell membranes from higher concentration to lower
concentration.
• Facilitated diffusion: uses a carrier protein to move
nutrients from higher concentration to lower concentration.
• Active absorption: involves a carrier protein as well as
energy to move nutrients (against a concentration gradient)
into absorptive cells.
• Phagocytosis and pinocytosis: Absorptive cell membrane
forms an indentation that engulfs a nutrient to bring it into
cell.
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Figure 3-16: Nutrient Absorption
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Figure 3-17: Parts of the Large Intestine
Five segments:
• Cecum
• Ascending colon
• Transverse colon
• Descending colon
• Sigmoid colon
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Large Intestine (Colon)
• No villi or enzymes
• Mucus-producing cells
• Absorption of water, some minerals, and vitamins
• Feces: consists of water, fiber, tough connective tissues,
bacteria, dead intestinal cells
• Microbiota: community of microorganisms coexisting on
and within human body. Over 500 different types of bacteria
in large intestine
• Probiotics: Microorganisms reside in large intestine that
can provide health benefits
• Prebiotics: Substances increase growth of probiotics
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Rectum
Last portion of large intestine
Muscular movements push feces into the anus.
Anal sphincters:
• Internal
• External (under voluntary control)
Relaxation allows elimination
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Accessory Organs
Gallbladder: attached to underside of liver for bile storage,
concentration, and secretion.
• Bile: released through common bile duct into first segment of
small intestine; essential for digestion and absorption of fat.
Liver: produces bile and releases unwanted substances that
travel with bile to gallbladder.
• Waste ends up in the small intestine, eventually in the large
intestine for excretion.
Pancreas: has both endocrine and digestive functions.
• Manufactures hormones such as insulin and glucagon.
• Produces “pancreatic juice,” a mixture of water, bicarbonate, and
variety of digestive enzymes.
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Table 3-2: Summary of Absorption Along the GI Tract
Organ
Primary Nutrients Absorbed
Stomach
Blank
Alcohol (20% of total)
Water (minor amount)
Small Intestine
Blank
Blank
Blank
Blank
Blank
Blank
Blank
Calcium, magnesium, iron, and other minerals
Glucose
Amino acids
Fats
Vitamins
Water (70% to 90% of total)
Alcohol (80% of total)
Bile acids
Large Intestine
Blank
Blank
Blank
Blank
Sodium
Potassium
Some fatty acids
Gases
Water (10% to 30% of total)
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Figure 3-18: Accessory Organs and Bile Transport
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Section 3.9 Concepts: The Human Microbiota
1. In simple terms, explain the differences among probiotics,
prebiotics, and postbiotics.
2. Other than yogurt, list two food sources of probiotic
microorganisms.
3. Describe two ways the gut microbiota may work to support
human health.
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Figure 3-19: Bacteria in the Gastrointestinal Tract
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Probiotics, Prebiotics, Synbiotics, and Postbiotics
• Probiotics: live microorganisms that have positive effects
on human health if they are consumed in sufficient
quantities.
• Prebiotics: Selectively fermented ingredient that results in
specific changes in the composition and/or activity of the
gastrointestinal microbiota, thus conferring benefits upon the
host.
• Synbiotics: Combination of pro- and prebiotics taken to
confer health benefits on the host.
• Postbiotics: Metabolic by-products of the microorganisms
that colonize the human body.
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The Human Microbiota: Immune Function
Healthy gut microbiota:
• crucial for proper immune system development and
maintenance
Gut-associated lymphoid tissues (GALT):
• much is in large intestine
• exposure to microorganisms promotes the maturation of the
immune cells
Beneficial strains of microorganisms:
•
directly compete with and reduce the activity of diseasecausing organisms in the GI tract
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Figure 3-20: Components of the Gut Microbiota
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Section 3.10 Concepts: Nutrient Storage Capabilities
1. What is the body’s most efficient form of energy storage?
2. Why is it important to consume nutrients daily?
3. When it comes to vitamins and minerals, is consuming
more than the RDA or AI a good way to ensure optimal
nutrition status? Why or why not?
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Nutrient Storage Capabilities
Human body must maintain reserves of nutrients.
• Storage capacity varies for each different nutrient.
Fat: stored mainly in adipose tissue.
Glucose and glycogen:
• Short-term storage in muscle and liver
• Blood maintains small reserve of glucose and amino acids.
Vitamin and minerals: storage varies
Balanced diet is safest means to acquire nutrients needed for
optimal health.
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Section 3.11 Concepts: Nutrition and Your Health—
Common Problems With Digestion
1. What is the leading cause of peptic ulcers?
2. Describe the relationship between spicy foods and ulcers:
Do spicy foods cause ulcers? Should a person with an
ulcer eat spicy foods?
3. What are the two best dietary strategies to prevent or treat
constipation?
4. What is the most important nutritional concern for a person
experiencing diarrhea?
5. Based on what you have learned about digestion and
absorption of nutrients, is taking laxatives an effective way
to prevent fat gain from excess calorie intake? Why or why
not?
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Heartburn
• 60 millions Americans experience heartburn.
• Also known as acid reflux.
• Results from stomach acid backing up into esophagus.
• Acid erodes the lining of the esophagus.
• Symptoms: pain, nausea, gagging, cough, hoarseness.
• Gastroesophageal reflux disease (GERD): recurrent,
serious form
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Figure 3-21: Heartburn
Heartburn is a
sign of reflux of
stomach acid into
the esophagus.
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Symptoms of GERD or Persistent Heartburn
• Difficulty swallowing or pain when swallowing
• Heartburn that has persisted for more than 10 years
• Initial onset of heartburn after age 50
• Heartburn that resists treatment with medications
• Sudden, unexplained weight loss
• Chest pain
• Blood loss or anemia
• Blood in stool or vomit
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Ulcers
Erosion of the lining in the esophagus, stomach, or upper
small intestine; also known as peptic ulcers.
Common causes:
• Acid secreted by stomach
• H. pylori infection
• Overuse of nonsteroidal anti-inflammatory drugs (NSAIDs)
Treatments:
• Antibiotics to eradicate H. pylori
• Acid-blocking medications (for example, proton pump
inhibitors)
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Table 3-3: Nutrition and Lifestyle Recommendations for
Care of Heartburn and Peptic Ulcers 1
Blank
Heartburn
Peptic Ulcers
Avoid smoking
X
X
Avoid large doses of aspirin, ibuprofen, and
other NSAID compounds unless a physician
advises otherwise
X
X
Achieve and maintain a healthy body weight
X
X
Eat small, low-fat meals
X
X
Limit alcohol consumption
X
X
Limit consumption of caffeine (for example,
coffee, some soft drinks)
X
X
Consume a nutritionally complete diet with
adequate fiber
X
X
Avoid tight-fitting clothing
X
Blank
Elevate the head of the bed 6 to 8 in.
X
Blank
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Table 3-3: Nutrition and Lifestyle Recommendations for
Care of Heartburn and Peptic Ulcers 2
Blank
Avoid foods that worsen symptoms:
Heartburn Peptic Ulcers
Blank
Blank
• Acidic foods (for example, orange juice, tomato
products)
X
X
• Highly spiced foods (for example, chili, cayenne,
and black pepper)
X
X
• Carbonated beverages
X
X
• Foods that relax the lower esophageal sphincter
(for example, peppermint, spearmint, chocolate)
X
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• Onions and garlic
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Avoid eating at least 3 to 4 hr before lying down
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Wash hands often and follow food safety guidelines
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91
Figure 3-22: Ulcer
J. James/Science Source
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92
Medicine Cabinet
Proton pump inhibitors
(PPIs): inhibit the ability of
gastric cells to secrete
hydrogen ions and thus
reduce acid production.
H2 blockers: impede
stimulating effect of
histamine on acidproducing cells in the
stomach.
Examples:
•
Omeprazole (Prilosec®)
• Lansoprazole (Prevacid®)
• Rabeprazole (Aciphex®)
• Esomeprazole (Nexium®)
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Examples:
• Cimetidine (Tagamet®)
• Nizatidine (Axid®)
• Famotidine (Pepcid®)
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Constipation
Difficult or infrequent evacuation of
the bowels.
Treatment:
• Increase fiber consumption.
• Drink adequate fluids, especially
water.
• Establish a regular bowel routine.
• Relaxation.
• Regular exercise.
Laxatives, with supervision of
primary care provider can lessen
constipation.
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C Squared Studios/Photodisc/Getty Images
Dried fruits, a natural
source of fiber, along with
adequate fluid can help
prevent constipation.
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Hemorrhoids
Swollen veins of rectum and anus; also called piles.
Caused by intense pressure during bowel movements.
• Stress to vessels from pregnancy, obesity, prolonged sitting,
violent coughing or sneezing, or straining during bowel
movements, particularly with constipation.
Results in itching and bleeding from anus.
Treatment includes warm bath and treating constipation.
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Figure 3-23: Diverticular Disease
• Diverticula: Pouches
that protrude through
the exterior wall of the
large intestine.
• Diverticulosis: The
condition of having
many diverticula in the
large intestine.
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96
Irritable Bowel Syndrome (IBS)
Affects 12% of adults.
Symptoms:
• Bloating, abdominal pain
• Diarrhea, constipation, or alternating episodes of both
• Visible abdomen distention
Treatment:
• Eliminate trigger foods (poorly digested carbohydrates)
• Follow low-FODMAP dietary pattern
• Moderate caffeine
• Small, frequent, low-fat meals
• Reduce stress, treat depression
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97
Magnificent Microbiome
Irritable Bowel Syndrome
• An imbalance between beneficial and pathogenic microbes in the
gut may play a role in the development of irritable bowel
syndrome.
• Microorganisms influence intestinal function in many ways:
• Stimulates the production of a protective layer of mucus.
• Affects the permeability of the intestinal lining.
• Upregulates or downregulates the inflammatory response.
• Affects nerve signals from the gut to the brain.
• Researchers are interested in the potential for foods or
supplements with probiotics or prebiotics to promote healthier gut
function in individuals with IBS.
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Low-FODMAP Dietary Pattern for IBS
FODMAPs:
• Fermentable
carbohydrates:
oligosaccharides,
disaccharides,
monosaccharides, and
polyols.
• May be poorly digested
and lead to GI symptoms
such as bloating, gas, and
diarrhea.
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Low-FODMAP Dietary
Pattern:
• Eliminate foods containing
FODMAPs: wheat, onions,
legumes, and dairy
products for several
weeks
• Gradually add back foods
• Determine which can be
tolerated, which should be
avoided long term.
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Diarrhea
Increased fluidity, frequency, or amount of bowel movements.
Causes:
• Infections by microorganisms.
• Malabsorption of dietary components (for example, sugar
alcohols or excess fiber).
Treatment:
• Prevent dehydration, plenty of fluid, electrolyte replacement.
• Seek medical attention if prolonged.
Serious danger for infants and elderly.
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Figure 3-24: Gallbladder and Gallstones
Affects 10% to 20% of
U.S. adults.
Symptoms:
• Upper right abdominal
pain
• Gas, bloating
• Nausea and vomiting
Treatment:
• Removal of gallbladder
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The Sydney Morning Herald/Fairfax Media/Getty Images
Gallbladder and gallstones
seen after surgical removal
from the body.
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Celiac Disease
Chronic, immune-mediated disease
• Precipitated by exposure to dietary protein gluten in
genetically predisposed people.
• Gluten: protein found in certain grains, wheat, rye, barley.
Affects approximately 1% of U.S. population.
Flattens villi.
Limits absorption of nutrients.
Treatment:
• Elimination of wheat, rye, and barley.
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Figure 3-25: Small Intestine and Celiac Disease
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103
Nonceliac Gluten Sensitivity
Also called gluten intolerance.
Experience symptoms after ingestion of gluten but no intestinal
damage.
• GI distress
• Fatigue, weakness
• Headache, muscle pain, joint pain
• Sleep disorders
Treatment:
• Elimination of wheat, rye, and barley.
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