The document discusses the gastrointestinal tract and common intestinal problems. It covers the structure and function of the lower GI tract. Common issues like constipation, intestinal gas, and diarrhea are explained in detail, including causes and treatment approaches. Specific conditions that can affect the small intestine, like celiac disease and inflammatory bowel disease, are outlined. Nutrition management for these diseases is also addressed.

1. GASTROINTESTINAL TRACT AND
NUTRITION
REFERENCES: ROLFES, S., WHITNEY, E. AND PINNA, K., 2015. UNDERSTANDING NORMAL & CLINICAL
NUTRITION. 11TH ED.
Marah Shakhshir
Nihal Natour
Marah Shakhshir MSc, Dietitian 1

2. Outcomes
1. Nutrition management of common conditions of the lower GI tract
2. Common Intestinal problems Constipation, Intestinal Gas, Diarrhea.
3. Examples of conditions affecting the small intestine include: celiac disease, Irritable
bowel disease, short bowel syndrome.
4. Celiac disease, identification, complications and dietary management
5. Irritable bowel disease, identification, complications and dietary management
6. Examples of conditions affecting the large intestine include: Irritable bowel
syndrome, Colostomies and Ileostomies, Diverticular Disease of the Colon.
Marah Shakhshir MSc, Dietitian 2

3. Lower GI tract
Marah Shakhshir MSc, Dietitian 3

4. Lower GI tract
 The lower gastrointestinal (GI) tract, which consists of the small intestine (duodenum,
jejunum, and ileum) and the large intestine (colon, rectum, and anal canal).
 The digestion and absorption of nutrients occur primarily in the small intestine.
 The pancreas and gallbladder support digestion by delivering digestive secretions to
the duodenum, the segment of small intestine closest to the stomach.
 The large intestine reabsorbs water and facilitates the elimination of waste material.
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5. Common Intestinal Problems
 Nearly all people experience occasional intestinal problems, which usually clear up without
medical treatment.
 Intestinal discomfort can sometimes drive a person to seek medical attention, however, and the
symptoms may be evidence of a serious intestinal disorder or other illness. The most common
intestinal problems are :
 Constipation
 Intestinal Gas
 Diarrhea
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6. Constipation
 A diagnosis of constipation is based, in part, on a defecation frequency of fewer than three bowel
movements per week.
 Other symptoms may include excessive straining during defecation, the passage of hard stools,
and incomplete evacuation.
 In some cases, a person’s perception of constipation may be due to a mistaken notion of what
constitutes “normal” bowel habits, so the person’s expectations about bowel function may need
to be addressed.
 The prevalence of constipation is higher in women than in men and is especially high in older
adults (65 years and older). Older adults tend to report problems with excessive straining and
hard stools rather than infrequent defecation.
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7. Causes of Constipation
 The risk of constipation is increased in individuals with a low-fiber diet, low food intake, inadequate fluid
intake, or low level of physical activity
 All of these factors can extend transit time, leading to increased water reabsorption within the colon and
dry, hard stools that are difficult to pass. Medical conditions often associated with constipation include
diabetes mellitus and hypothyroidism.
 Neurological conditions such as Parkinson’s disease and multiple sclerosis may cause motor problems
that lead to constipation.
 During pregnancy, women often experience constipation due to hormonal changes and the pressure of
the enlarged uterus on the intestines. Constipation is also a common side effect of several classes of
medications and some dietary supplements, including anticholinergics, calcium channel blockers,
diuretics, opiate-containing analgesics, and calcium and iron supplements.
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8. Treatment of Constipation
 In individuals with a low fiber intake, the primary treatment for constipation is a gradual increase in
fiber intake to at least 20 to 25 grams per day
 High-fiber diets increase stool weight and fecal water content and promote a more rapid transit of
materials through the colon. Foods that in- crease stool weight the most include wheat bran, fruits,
and vegetables
 Bran intake can be increased by adding bran cereals and whole-wheat bread to the diet or by mixing
bran powder with beverages or foods
 The transition to a high-fiber diet may be difficult for some people because it can increase intestinal
gas, so high-fiber foods should be added gradually, as tolerated
 Fiber supplements such as methylcellulose (Citrucel), psyllium (Metamucil, Fiberall), and
polycarbophil (Fiber-Lax) are also effective.**
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9. Treatment of Constipation
 Several other dietary or lifestyle measures may help to relieve constipation.
 Consuming adequate fluid (1.5 to 2 liters daily) enhances the effect of an increased fiber intake on
stool frequency, and an appropriate fluid intake prevents excessive reabsorption of water from the
colon, resulting in wetter stools
 Consuming prunes or prune juice is often recommended because prunes contain compounds that
have a mild laxative effect
 Skipping breakfast is discouraged, as colonic motility is highest after
a morning meal.
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10. Laxatives
 Laxatives may improve a constipation problem by increasing stool weight, increasing
the water content of the stool, or stimulating peristaltic contractions.
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11. Medical Interventions
 For patients with severe constipation who do not respond to dietary or laxative
treatments, physicians may prescribe medications
 Surgical interventions are a last resort and include colonic resections and colostomy
operations
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12. Intestinal Gas
 increased intestinal gas (flatulence) may be an unpleasant side effect of consuming a high-fiber
diet.
 A common Cause : A.dietary fibers are not digested, they pass into the colon and are fermented by
bacteria, which produce gas as a by-product (soluble fibers are more readily fermented than the
insoluble fibers).
 B. Other incompletely digested or poorly absorbed carbohydrates have similar effects; these
include the indigestible carbohydrates in beans (raffinose and stachyose), lactose (in lactose-
intolerant individuals), fructose, some sugar alcohols (such as sorbitol, xylitol, and mannitol), and
some forms of resistant starch, found in grain products and potatoes. For purposes of nutrition
therapy, fermentable dietary carbohydrates are often referred to as FODMAPs*.
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13. Intestinal Gas
 Both corn and wheat are sources of resistant starch; wheat also contains
oligosaccharides that resist digestion. Carbonated beverages contain dissolved
carbon dioxide gas, which contributes to intestinal gas.
 Most people who self-diagnose a flatulence problem have no more intestinal
gas than others. Some individuals who experience recurrent bloating and
abdominal pain are later diagnosed with irritable bowel syndrome (IBS)
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14. Diarrhea
 Diarrhea is characterized by the passage of frequent, watery stools. In most cases, it lasts for
only a day or two and subsides without complication.
 Severe or persistent diarrhea, however, can cause dehydration and electrolyte im- balances.
 If chronic, it may lead to weight loss and malnutrition.
 Diarrhea may be accompanied by other symptoms, such as fever, abdominal cramps,
dyspepsia, or bleeding, which help in diagnosing the cause.
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15. Causes of Diarrhea
 Diarrhea is a complication of multiple GI disorders and may also be caused by
infections, medications, and dietary substances
 A. inadequate fluid reabsorption in the intestines,
 B. sometimes in conjunction with an increase in intestinal secretions.
 Could be diagnosed as Osmotic or Secretory diarrhea
 Could be Acute or chronic.
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16. Osmotic/Secrotary Diarrhea
 In osmotic diarrhea, unabsorbed nutrients or other substances attract water to the colon and increase
fecal water content.
Causes : 1.Include high intakes of poorly absorbed sugars (such as sorbitol, mannitol, or fructose)
2. Lactase deficiency (which causes lactose malabsorption)
3. Ingestion of laxatives that contain magnesium or phosphates
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17. Osmotic/Secretory Diarrhea
 In secretory diarrhea, the fluid secreted by the intestines exceeds the amount that can be
reabsorbed by intestinal cells.
Causes:
1. Secretory diarrhea is often due to foodborne illness
2. Can also be caused by intestinal inflammation and various chemical substances such as
medications.
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18. Acute/Chronic Diarrhea
 Acute cases of diarrhea suddenly start and may persist for several weeks.
 Most often caused by viral, bacterial, parasitic, or protozoan infections but may also occur as
a side effect of medications
 Chronic diarrhea persists for about 4 weeks or longer.
 Can result from chronic infections, malabsorptive disorders (ex: Lactose Intolerance),
inflammatory diseases, motility disorders, radiation treatment, and many other conditions.
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19. Diarrhea Treatment
 Correcting the underlying medical problem is the first step in treating diarrhea:
A. If medications are causing the problems, then others should be prescribed.
B. If Certain type of food, alternatives should be introduced.
C. Some Bulking agents can be used (can help to reduce the liquidity of the stool)
D. If chronic diarrhea does not respond to treatment, antidiarrheal drugs may be prescribed to
slow GI motility or reduce intestinal secretions.
E. Probiotics* may be beneficial for treating certain types of diarrhea—especially infectious
diarrhea
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20. Nutrition Therapy for Diarrhea
 Nutrition care depends on the cause of diarrhea and its severity and duration.
 The dietary treatment initially recommended is often a low-fiber, low-fat, lactose-free diet
which limits foods that contribute to stool volume, such as those with significant amounts of
fiber, resistant starch, fructose, sugar alcohols, and lactose (in lactose-intolerant
individuals)
 Foods to avoid: Fructose and sugar alcohols, milk products may worsen osmotic diarrhea in
persons who are lactose intolerant, fatty foods, Gas-producing foods(can cause additional
Discomfort)
 Fluid intakes must usually be increased to replace fluid losses, patients should avoid
caffeinated coffee and tea because caffeine stimulates GI motility and can thereby reduce
water reabsorption
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21. Conditions Affecting the Small Intestine
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Celiac Disease
Inflammatory Bowel Disease
Short Bowel Syndrome

22. Conditions Affecting the Small
Intestine
 Celiac disease and the inflammatory bowel diseases, are intestinal illnesses that can
damage the intestinal mucosa.
 Short bowel syndrome, the malabsorption disorder that results when a substantial
portion of the small intestine is surgically removed
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23. Celiac Disease
Celiac disease is an immune disorder characterized by an abnormal immune response to a protein
fraction in wheat gluten and to related proteins in barley and rye
 The reaction to gluten causes severe damage to the intestinal mucosa and subsequent
malabsorption
 The damage may be restricted to the duodenum or may involve the full length of the small
intestine.
 It can develop at any age, although symptoms are most likely to develop:
 During early childhood – between 8 and 12 months old, although it may take several
years before a correct diagnosis is made
 In later adulthood – between 40 and 60 years of age
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24. Celiac Disease
 Symptoms
1. GI disturbances such as diarrhea, steatorrhea, and flatulence
2. Because lactase deficiency can result from the mucosal damage, milk products
may exacerbate GI symptoms
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25. Consequences of Celiac Disease
1. Nutrient Malabsorption: the villi may be shortened or absent, resulting in a significant
reduction in mucosal surface area (and, therefore, in the number of cells that digest and absorb
nutrients)
2. Deficiencies of fat-soluble vitamins (A, D, E, and K), iron, folic acid, and calcium are common
in people afflicted with celiac disease.
3. Children with celiac disease often exhibit poor growth, low body weight, muscle wasting, and
anemia.
4. Adults may develop anemia, bone disorders, neurological symptoms, and fertility problems.
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26. Celiac Disease
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27. Nutrition Therapy for Celiac Disease
 Lifelong adherence to a gluten-free diet (Even small amounts of gluten may cause
symptoms in some people)
 Lactose Containing Foods
 Dietary supplements
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28. Gluten-free diet
■ This diet eliminates foods that contain wheat, barley, and rye
■ patients need to check ingredient lists on food labels carefully
■ Could be in coffee substitutes, communion wafers, imitation meats, malt syrup, medications,
salad dressings, and soy sauce
■ Gluten-free products can be purchased to replace common food items such as bread, pasta, and
cereals
■ Allowed cereal and grain products include: oats, quinoa, rice, potato, corn.
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29. Inflammatory Bowel Diseases (IBD)
 Inflammatory bowel diseases are chronic inflammatory disorders characterized by
abnormal immune responses to microbes that inhabit the GI tract.
 Genetic and environmental factors contribute to the development of these diseases.
 Diagnosed in two forms: Crohn’s disease and ulcerative colitis.
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30. IBD
 Crohn’s disease usually involves the small intestine and may lead to nutrient
malabsorption
 Ulcerative colitis (UC): affects the large intestine, where little nutrient
absorption occurs
 Both diseases are characterized by periods of active disease interspersed with
periods of remission. Nutrient losses can result from tissue damage, bleeding,
and diarrhea.
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31. Crohn’s Disease
 An inflammatory bowel disease usually occurs in the lower portion of the small intestine
and the colon.
 Crohn’s disease may occur in any region of the GI tract
 Nearly half of patients require surgery within 10 years of diagnosis.
 Patients with Crohn’s disease are also at increased risk of developing intestinal cancers.
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32. Crohn’s disease and Nutrition
1. Malnutrition may result from poor food intake
2. Malabsorption
3. Diarrhea
4. Bleeding
5. Nutrient losses (especially of protein) from inflamed tissues
6. Increased needs due to inflammation, and surgical resections that shorten the small intestine.
7. Malabsorption of fat, fat-soluble vitamins, calcium, magnesium, and zinc (the minerals bind to
the unabsorbed fatty acids) – In some cases because bile acids may become depleted.
8. Vitamin B12 absorption, deficiency
9. Anemia may result from bleeding, inadequate absorption
10. Anorexia often develops because of abdominal discomfort and the effects of cytokines produced
during the inflammatory process.
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33. Ulcerative Colitis
 An inflammatory bowel disease that includes the rectum and the colon
 During active episodes, patients may have frequent, urgent bowel movements that are
small in volume and contain blood and mucus
 Symptoms
1. May include diarrhea, constipation, rectal bleeding, and abdominal pain.
 Although mild disease may cause few complications, weight loss, fever, and weak- ness
are common when most of the colon is involved
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34. Nutrition Therapy for Crohn’s Disease
 Because it can lead to protein-energy malnutrition, a well planned diet is recommended
to avoid nutrient deficiencies and growth failures.
1. High-kcalorie, high-protein diets may be prescribed to prevent or treat malnu- trition or
promote healing
2. Vitamin and mineral supplements
Nutrients at risk include iron, zinc, magnesium, calcium, vitamin D, folate, and vitamin B12
3.. tube feedings are used to supplement the diet
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35. Nutrition Therapy for Crohn’s Disease
 During disease flare-ups:
1. Low-fiber, low-fat diet
2. Small frequent meals
3. In case of diarrhea, flatulence : avoidance of milk
4. Patients with diarrhea should make sure they obtain adequate fluids to prevent
dehydration
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36. Nutrition Therapy for Ulcerative Colitis
 Few adjustments
 Dietary adjustments are based on the extent of bleeding
 Adequate protein, energy, fluid, and electrolytes need to be provided.
 A low-fiber diet may reduce irritation by minimizing fecal volume
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37. Conditions Affecting the Large Intestine
Irritable Bowel Syndrome
Diverticular Disease of the Colon
Colostomies and Ileostomies
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