Nutritional Management of Crohn’s Disease
By Stephanie Fawbush
Family history of GI problems Friends with Crohn’s Many questions about nutritional guidance from these friends and family
Why Crohn’s Disease?
Crohn’s:Discussion of Disease
Form of inflammatory bowel disease (IBD) Autoimmune, chronic inflammatory
condition of the GI tract Marked by an abnormal response by the
body’s immune system Diseased segments separated by normal
bowel segmentso “skip lesions”
What is Crohn’s Disease?
IBD: Crohn’s vs. Ulcerative Colitis
Affects an estimated 0.1-16/100,000 people
IBD has an overall health care cost of more than $1.7 billionoOne of the 5 most prevalent GI disease
burdens in the US 75% of Crohn’s patients will need
surgery in their lifetime
Facts About Crohn’s
Upper GIo Esophagus o Stomach oDuodenum
Lower GIo Small Intestine o Large Intestine o Colon
The GI Tract
The main functions of the GI system are:oDigestionoAbsorption
The GI Tract
Oral phaseo Mastication and mixing of food with salivary
fluid and enzymes. Gastric phaseo Pepsin and gastric acid start to form the bolus
into chyme.o Chyme delivered to the small intestine for
mixing with enzymes. Intestinal phaseo Disaccharides, peptidases, and cholecystokinin
Digestion
Secretes protease and hydrochloric acid
The food bolus is churned in the stomach through peristalsis.o 40 minutes to 4
hours Main function is
digestiono Small amounts of
absorption
Stomach
Passage of molecular nutrients into the bloodstream from the intestinal cells
Absorption
Site of chemical digestion and absorption
Three sections:o Duodenumo Jejunumo Ileum
Small Intestine
Three sections:o Caecumo Colono Rectum
Compacts and stores fecal matter before it is passed from the anus.
Large Intestine
ABSORPTION
Cause is not completely understood Involves the interaction of the GI immunologic
system and genetic and environmental factors Increased exposure, decreased defense
mechanisms, or decreased tolerance to some component of the GI microflora may occur
Major environmental factors include:o Resident and transient microorganisms in the GI
tracto Dietary components
Pathophysiology
Chronic inflammation from T-cell activation leading to tissue injury is implicated.
T-cells stimulate the inflammatory response. o Release nonspecific inflammatory
substances, which result in direct injury to the intestine.
Pathophysiology
Pathophysiology
Transmural inflammation results in thickening of the bowel wall and narrowing of the lumen.
As Crohn’s disease progresses, it is complicated by:o Obstruction or deep
ulceration leading to fistulization
o Microperforationo Abscess formationo Adhesionso Malabsorption
Cramps Loss of
appetite Tenesmus Diarrhea Weight loss Constipation Fistulas Ulcers Rectal bleeding Swollen gums Anemia
Mouth sores Nutritional
deficiencies Abscesses Anal fissures Hemorrhoids Fever Fatigue Eye
inflammation Joint pain
Signs & Symptoms
Multistep process Includes assessing:o Patient’s medical historyo Physical examo Lab valueso Medical tests
Diagnosis
Main risk factors include: o Genetics (Jewish population)o Smoking (doubles the risk)o Dieto Infectious agentso Immunological factors
Diagnosis
Signs include: Abdominal mass Skin rash Swollen joints Weight loss Mouth ulcers
Diarrhea Constipation Loss of appetite
Diagnosis:Physical Exam
Albumin C-reactive protein Erythrocyte
sedimentation rate Fecal fat Hgb Complete blood count
Diagnosis:Lab Tests
Colonoscopy Barium enema CT scan Endoscopy MRI Enteroscopy Stool culture
Diagnosis:Procedures
No cure for Crohn’s disease Treatments available to make Crohn’s
more manageable for patients Times between flare-ups can be
decreased through medical and nutritional management
Prognosis
Fistulas Malabsorption Obstruction Colon cancer
Complications of Crohn’s
Anti-diarrheal agents o Diphenoxylate, loperamide,
and codeine
Anti-inflammatory drugso 5-ASA agents (Asacol,
Canasa, Pentasa), Sulfasalazine (Azulfidine)
Constipation management o Laxatives, Metamucil,
Citrucel
Pain management
o Tylenol
Corticosteroidso Budesonide
Antibioticso Ampicillin, sulfonamide,
cephalosporin, tetracycline, metronidazole
Anti-TNF alpha therapyo Remicade
Biologic therapy o Humira, Cimzia, Tysabri
Medication Management
Bowel resection Total abdominal
colectomy Colostomy Ileostomy Total proctocolectomy
with ilesotomy
Surgical Management
Crohn’s:Medical Nutrition Therapy
Patients are considered to be at significant nutritional risk:o Est. 60-75% of patients will experience malnutrition
Nutrition therapy is used to:o Reduce the inflammatory response in the diseaseo Correct deficiencieso Ensure adequate maintenance of nutritional status
Multidisciplinary approach
MNT
Restore and maintain the patient’s nutritional status.
Replace fluid and electrolytes lost Monitor mineral and trace element levels
carefully Promote weight gain or prevent losses Reduce the inflammatory process Replenish nutrient reserves Promote healing
MNT: Objectives
First step in the Nutrition Care Process Includes:o Anthropometricso Biochemical datao Clinical datao Diet history
Assessment
Kcal/kg o Range from 15 kcal/kg-45 kcal/kg
Harris-Benedict equation: o Men: 66 + 13.7W + 5H - 6.8A=REE x stress
factor x activity factoro Women: 65.6 + 9.6W + 1.8H – 4.7A= REE x
stress factor x activity factor
Assessment:Calorie Needs
Protein is important to prevent muscle wasting and malnutrition.
Impact of protein-calorie malnutrition as a prognostic factor is demonstrated as greater mortality in IBD patients.
Calculated using gm protein/kgo Range from 1-2 gm/kg
Assessment:Protein Needs
‘PES statement’ o Problem/nutrition diagnosis, etiology, and
signs/symptoms. Diagnoses that could apply to a patient with
Crohn’s:o Inadequate oral intake (NI-2.1)o Inadequate fluid intake (NI-3.1)o Malnutrition (NI-5.2)o Inadequate mineral intake (NI-5.10.1)o Underweight (NC-3.1)o Unintended weight loss (NC-3.2)
Diagnosis
Improved nutritional status can reduce side effects of Crohn’s and improve quality of life.
Nutrition education is key Extent of nutrition intervention will depend
on:o Functional status of the GI tracto Extent of diarrheal outputo Obstructiono Surgical procedureso Bleeding
Interventions
When a patient is admitted with a severe Crohn’s flare, the following nutritional progression is recommended:o Nutrition support: enteral feedings or total
parenteral nutrition.o Progress to low-fat, low-fiber, high-protein,
high-kilocalorie, small, frequent meals with return to normal diet as tolerated.
Interventions
Maintain a low-fiber diet while experiencing a flair.
Once flairs have been resolved, return to a normal diet.
Gradually add small amounts of foods with fiber back into diet as tolerated. o Small amounts of whole grain foods and higher-fiber fruits and vegetables.
Interventions:Low Fiber Diet
Recommended foods during a Crohn’s flair:o Milk: Low fat milk products (skim milk, low fat cottage
cheese, low fat yogurt)o Grains: Grains with less than 2 grams of fiber per
serving (refined grains, white rice, white bread)o Vegetables: Well cooked vegetables without seeds,
potatoes without skin, and lettuceo Fruit: Fruit juice without pulp, canned fruit in
juice/light syrup, peeled fruitso Fat: Less than 8 tsp fats per dayo Meat: Well cooked meats, eggs, smooth nut butters,
and tofu
Interventions:Low Fiber Diet
Helpful if the patient has trouble digesting or absorbing fat.
Can help prevent uncomfortable side effects, such as diarrhea, bloating, and cramping.
However, some studies recommend that fat should only be avoided if the patient is experiencing steatorrhea.
Interventions:Low Fat Diet
Maximize calorie and protein intake. Encourage the patient to eat small meals or snacks
every 3-4 hours. Other recommendations could include:o Avoiding foods high in oxalateo Increasing antioxidant intakeo Supplementation with omega-3-fatty acids and
glutamine o Using probiotics and prebiotics
Interventions:Other Recommendations
TEN with a liquid formula TEN can be used in
combination with oral feeds.o Tube feeds with added
glutamine o Polymeric formulaso Low fiber formulas
Nocturnal tube feeds Times when the gut cannot be
used Perioperative PN may reverse
malnutrition
Interventions:Nutrition Support
Providing the patient with liquid formulas only and stopping oral feedings. o Carried out six-to-eight weeks
Demonstrated to lead to mucosal healing.o Result in fewer exacerbations and trips to the
hospital. Well-proven therapy for the management of
Crohn’s disease in the pediatric population.
Interventions:Exclusive Enteral Nutrition (EEN)
Vitamin D Vitamin E Zinc Calcium Magnesiu
m
Folate Thiamine Vitamin
B12 Ferritin Iron
Interventions:Supplementation
Four labs to pay special attention to:o Vitamin Do Ferritino Irono Zinc
Interventions:Supplementation
Nutrition care indicators will reflect a change as a result of nutrition care.
Things that can be monitored and evaluated include:o Food/nutrition-related history outcomeso Anthropometric measurement outcomeso Biochemical data, medical tests, and
procedure outcomeso Nutrition-focused physical finding outcomes
Monitoring & Evaluation
Crohn’s:Presentation of the
Patient
J.P. was a 43 year old white female
Admitted to PPMC on October 25, 2012
Dx: Crohn’s flairo She presented with several
weeks of loose stools containing mucous and blood along with abdominal pain.
PMH: Crohn’s disease & asthma
PSH: Tonsillectomy
The Patient: J.P.
Diagnosed with Crohn’s in 2006 Controlled on Pentasa ever since with only
intermittent symptoms Began to have increased symptoms of
abdominal pain, frequent blood/mucous bowel movements, and oral ulcers in August 2012.
At admission, having blood/mucous bowel movements every hour.
Decreased oral intake 2/2 abdominal pain
About J.P.
Crohn’s:Medical Hospital
Course
J.P. experienced interventions regarding the following medical problems while in the hospital:o Crohn’s flare o New enterovaginal fistula o Hemorrhoidso Anal fissureo Bilateral avascular necrosis w/o
collapse of subchondral plate
Medical Hospital Course
October 26, 2012 o C diff, crypto, and giardia negative. o HBV & HCV negative. o Colonoscopy
External skin tags Ulceration of the entire rectum from anus to 25cm Ulcerated mucosa sigmoid in the descending and transverse colon Areas of normal-appearing mucosa between the affected areas. Area of mucosal tag/polyps that numbered >10 in the transverse
colon. The terminal ileum appeared to be normal to 10cm. Cecum and rectosigmoid colon showed acute/chronic inflammation,
cryptitis, crypt abscess, and architectural disarray.o Mild gastritis in the antrum. o Lastly, an EGD was performed, which showed mildly
erythematous antral mucosa.
Medical Hospital Course
October 28, 2012o Stool culture, PPD read, & hepatitis B surface antibody negative
November 1, 2012o MRI of the pelvis
Fistula between the anterior aspect of the distal rectum to the left side of the posterior vagina with small collection.
Mildly active Crohn’s disease involving the region of the terminal ileum.
B/l femoral avascular/osteonecrosis without the collapse of the subchondral plate.
November 2, 2012o Blood cultures were negative to date; urinalysis benign
November 7, 2012o Discharged
Medical Hospital Course
10/25 10/27 10/28 10/29 10/30 10/31 11/2 11/4 11/6
Na 135 (L) 135 (L) 139 138 138 139 134 (L) 137 137
K 4.3 5 4 3.9 3.6 4.1 4.1 4 3.9
Cl 102 104 107 103 105 105 98 (L) 106 105
CO2 26 23 24 29 27 26 29 25 27
BUN 4 (L) 3 (L) 5 (L) 4 (L) 3 (L) 6 (L) 7(L) 4(L) 6(L)
Creatinine 0.61 0.73 0.86 1.15 (H) 0.7 0.76 0.79 0.68 0.82
Ca 8.7 (L) 8.9 8.6 (L) 8.4 (L) 8.4 (L) 8.6 (L) 8.2 (L) 8.3 (L) 8.7 (L)
Glucose 77 200 (H) 98 94 117 112 92 108 30
Mg 2.1
Phosphate 4
J.P.’s Labs
Crohn’s:Nutrition Hospital
Course
J.P. was picked up by clinical nutrition on day 7 of her admission.
Clinical nutrition was consulted for decreased PO intakeo Wanted a calorie count to be
initiated. J.P. was assessed three times
during her stay at PPMC.
Nutrition Hospital Course
Initial Assessment:11/1/12
Nutrition Assessment 11/1/2012 14:29 by SFHeight 68 inWeight 154 lb/69.9 kgUBW 155 lbWt change prior to admission None per ptBMI 23.4Significant Medications SSI, Methylprednisolone, Dilaudid, PentasaLabs 11/1-BUN 6 (Low), Ca 8.6 (Low)Complementary Therapies MultivitaminSkin Integrity IntactCurrent Diet Order GI soft/Low fiberNutrition RequirementsTotal daily calorie needs 2097 kcals (using 30 kcals/kg)Daily protein needs 69.9 g (1 kcal/kg)Daily fluid needs 2097 (using 1 kcal/ml)
Assessment/Diagnosis
Nutrition Summary Nutrition consult for calorie count. Pt reports ok appetite PTA.Appetite has been improving and PO intake of ~75% over the past day. Pt denied any recent wt loss. Denies N/V. Loose stools w/ blood/mucous. Calorie count starting at lunch. Pt agreed to some nutrition education so discussed Crohn’s nutrition education with patient. Discussed Low Fiber Nutrition Therapy and IBD Nutrition Therapy
Nutrition Diagnosis Altered GI function related to alterations in GI tract structure and function secondary to Crohn’s disease as evidenced by loose stools with blood/mucous.
Initial Assessment:11/1/12
Nutrition Interventions Nutrition Prescription: GI soft/low fiber dietInterventions:1) Diet w/ goal to meet >75% estimated energy needs by
reassessment
Clinical Nutrition Recommendations
-Continue with current diet regimen-Continue calorie count for 3 days-Recommend Omega 3 supplement-Recommend multivitamin-Encourage PO intake-If calorie count reveals pt is not meeting calorie needs, consider adding supplement
Complexity of Care Level 1 (follow up in 3 days)Monitoring and Evaluation
Indicators: total energy intakeCriteria: Pt to meet >75% estimated energy needs by reassessment
Initial Assessment:11/1/12
Medications: Methylprednisolone, Dilaudid, MVI, Fish oil supplement, Ca+Vit D supplement, Pentasa, Prednisone, Remicade
Labs: Na 134 (Low), BUN 7 (Low), Ca 8.2 (Low) Summary: 24 hour calorie count- 1233 kcals, 53.4 g
protein (meets 59% kcal needs, 76% protein needs) Recommendations: o Continue with current diet regimeno Continue calorie count through breakfast 11/4; will
determine need for supplemento Encourage PO intake
Follow Up:11/2/12
Medications: Dilaudid, MVI, Fish oil supplement, Ca+Vit D supplement, Pentasa, Prednisone, Remicade
Labs: BUN 4 (Low), Ca 8.3 (Low) Summary: 3 day calorie count met 54% kcal
needs, 74% protein needs. Discussed supplements with patient to help her meet her energy goals. Pt agreeable to try Ensure with meals.
Recommendations: o Continue with current diet regimeno Add Ensure TIDo Encourage PO intake
2ND Follow Up:11/4/12
Crohn’s:Critical Comments
Ask for a lab panel that includes vitamin D, zinc, iron, and ferritin.
Re-assess protein needs o I would estimate her protein needs to be about
1.3-1.5 g/kg instead of 1 g/kg in original assessment.
Implement an oral supplement earlier into her stay
Critical Comments
Crohn’s:Summary
Recommendations are constantly changing in the world of nutrition. o Vital to remain knowledgeable and up to date
on current research in order to provide the best patient care.
Dietitians are an integral part of the multidisciplinary team in treating patients with Crohn’s.o RD’s need to make sure that they stay
involved in the patient’s care and provide valuable insight to the team.
Summary
THANKS TO:-Elizabeth Stabler RD, LDN-Lauren Ginipro RD, LDN-Erin Gerlach RD, LDN-Arpana Bidnur RD, LDN-Theodora Wong RD, LDN
And all the dietitians at:-Nazareth Hospital-Children’s Hospital of Philadelphia-Hospital of the University of Pennsylvania
References Crohn’s disease and ulcerative colitis overview. Academy of Nutrition and Dietetics, Nutrition Care Manual. 2012.
Available at: http://www.nutritioncaremanual.org/ content.cfm?ncm_content_id=91936. Accessed December 27, 2012.
Crohn’s disease. U.S. National Library of Medicine. 2012. Available at: http://www. ncbi.nlm.nih.gov/pubmedhealth/PMH0001295/. Accessed December 27, 2012.
Mosby’s Dictionary of Medicine, Nursing, and Health Professions. 8th ed. St. Louis: Mosby Elsevier; 2009. Inflammatory bowel disease (IBD). Centers for Disease Control and Prevention. 2012. Available at:
http://www.cdc.gov/ibd. Accessed December 27, 2012. Mahan LK, Escott-Stump S. Krause’s Food & Nutrition Therapy. 12th ed. St. Louis: Saunders Elsevier; 2008. Images. Clinical Care Options. 2012. Available at: www.clinicaloptions.com. Accessed December 27, 2012. Digestive disorders health center. WebMD. 2009. Available at: http://www.webmd. com/digestive-disorders/picture-of-
the-stomach. Accessed January 4, 2013. Mandal A. What does the small intestine do? News-Medical. 2012. Available at:
http://www.news-medical.net/health/What-Does-the-Small-Intestine-Do.aspx. Accessed December 28, 2012. Large intestine. Medline Plus. 2012. Available at: http://www.nlm.nih.gov/ medlineplus/ency/imagepages/19220.htm.
Accessed January 4, 2013. Ghazi L. Crohn’s disease. Medscape. 2013. Available at: http://emedicine.medscape.com /article/172940-
overview#a0104. Accessed January 4, 2013. Waye JD, Palmon R. Colonoscopy in inflammatory bowel disease. Pract Gastroenterol. 2006; 25: 14-29. Barrett JC et al. Genome-wide association defines more than 30 district susceptibility loci for Crohn’s disease. Nat
Genet. 2008; 8: 955-962. Shanahan F. Crohn’s disease. The Lancet. 2002; 359: 62-69. Crohn’s disease. US News Health. 2009. Available at: http://health.usnews.com/health-conditions/digestive-
disorders/crohns-disease/tests. Accessed January 5, 2013. Crohn’s disease health center. WebMD. 2012. Available at: http://www.webmd.com/ ibd-crohns-disease/crohns-
disease/inflammatory-bowel-disease-and-colon-cancer. Accessed January 4, 2013. Escott-Stump S. Nutrition and Diagnosis-Related Care. 7th ed. Baltimore: Lippincott Williams & Williams; 2012. Total abdominal colectomy. Medline Plus. 2013. Available at: http://www.nlm.nih.gov/
medlineplus/ency/article/007379.htm. Accessed January 4, 2013. Total proctocolectomy with ileostomy. Medline Plus. 2013. Available at: http://www.
nlm.nih.gov/medlineplus/ency/article/007381.htm. Accessed January 4, 2013. Krok KL, Lichenstein GR. Nutrition in Crohn disease. Curr Opin Gastroenterol. 2003; 19: 148-153.
References
Crohn’s disease and ulcerative colitis overview. Academy of Nutrition and Dietetics, Nutrition Care Manual. 2012. Available at: http://www.nutritioncaremanual.org/ content.cfm?ncm_content_id=91936. Accessed December 27, 2012.
Crohn’s disease. U.S. National Library of Medicine. 2012. Available at: http://www. ncbi.nlm.nih.gov/pubmedhealth/PMH0001295/. Accessed December 27, 2012.
Mosby’s Dictionary of Medicine, Nursing, and Health Professions. 8th ed. St. Louis: Mosby Elsevier; 2009. Inflammatory bowel disease (IBD). Centers for Disease Control and Prevention. 2012. Available at: http://www.cdc.gov/ibd. Accessed December 27,
2012. Mahan LK, Escott-Stump S. Krause’s Food & Nutrition Therapy. 12th ed. St. Louis: Saunders Elsevier; 2008. Images. Clinical Care Options. 2012. Available at: www.clinicaloptions.com. Accessed December 27, 2012. Digestive disorders health center. WebMD. 2009. Available at: http://www.webmd. com/digestive-disorders/picture-of-the-stomach. Accessed January 4,
2013. Mandal A. What does the small intestine do? News-Medical. 2012. Available at: http://www.news-medical.net/health/What-Does-the-Small-Intestine-
Do.aspx. Accessed December 28, 2012. Large intestine. Medline Plus. 2012. Available at: http://www.nlm.nih.gov/ medlineplus/ency/imagepages/19220.htm. Accessed January 4, 2013. Ghazi L. Crohn’s disease. Medscape. 2013. Available at: http://emedicine.medscape.com /article/172940-overview#a0104. Accessed January 4, 2013. Waye JD, Palmon R. Colonoscopy in inflammatory bowel disease. Pract Gastroenterol. 2006; 25: 14-29. Barrett JC et al. Genome-wide association defines more than 30 district susceptibility loci for Crohn’s disease. Nat Genet. 2008; 8: 955-962. Shanahan F. Crohn’s disease. The Lancet. 2002; 359: 62-69. Crohn’s disease. US News Health. 2009. Available at: http://health.usnews.com/health-conditions/digestive-disorders/crohns-disease/tests. Accessed
January 5, 2013. Crohn’s disease health center. WebMD. 2012. Available at: http://www.webmd.com/ ibd-crohns-disease/crohns-disease/inflammatory-bowel-disease-
and-colon-cancer. Accessed January 4, 2013. Escott-Stump S. Nutrition and Diagnosis-Related Care. 7th ed. Baltimore: Lippincott Williams & Williams; 2012. Total abdominal colectomy. Medline Plus. 2013. Available at: http://www.nlm.nih.gov/ medlineplus/ency/article/007379.htm. Accessed January 4, 2013. Total proctocolectomy with ileostomy. Medline Plus. 2013. Available at: http://www. nlm.nih.gov/medlineplus/ency/article/007381.htm. Accessed
January 4, 2013. Krok KL, Lichenstein GR. Nutrition in Crohn disease. Curr Opin Gastroenterol. 2003; 19: 148-153.
Crohn’s disease and ulcerative colitis nutrition prescription. Academy of Nutrition and Dietetics, Nutrition Care Manual. 2012. Available at: http://www.nutritioncaremanual .org/content.cfm?ncm_content_id=92004. Accessed February 1, 2013. Naik AS, Venu N. Nutritional care in adult inflammatory bowel disease. Pract Gastroenterol. 2012; 106: 18-28. Academy of Nutrition and Dietetics. International Dietetics & Nutrition Terminology Reference Manual. 3rd ed. Chicago: American Dietetic Association; 2011. Eiden K. Nutritional considerations in inflammatory bowel disease. Pract Gastroenterol. 2003; 33-50. Crohn’s disease and ulcerative colitis nutrition prescription. Academy of Nutrition and Dietetics, Nutrition Care Manual. 2012. Available at: http://www.nutritioncaremanual. org/content.cfm?ncm_content_id=92005. Accessed February 1, 2013.Nutrition therapy for inflammatory bowel diseae. Academy of Nutrition and Dietetics, Nutrition Care Manual. 2012. Available at: http://www.nutritioncaremanual.org /vault/editor/Docs/Crohns_IBDNutritionTherapy1.pdf. Access February 1, 2013. Fat-restricted nutrition therapy. Academy of Nutrition and Dietetics, Nutrition Care Manual. 2012. Available at: http://www.nutritioncaremanual.org/vault/editor/Docs/Fat-RestrictedNutritionTherapy2.pdf. Access February 1, 2013. Johnson T, et al. Treatment of active Crohn’s disease in children using partial enteral nutrition with liquid formula: a randomized control trial. Gut. 2006; 55: 356. Newby EA, et al. Interventions for growth failure in childhood Crohn’s disease. Cochrane Database Syst Rev. 2005; 3:CD003873.Day AS, Otley AR. Exclusive enteral nutrition: a nutritional approach to Crohn’s disease. Pract Gastroenterol. 2009; 51: 34-40. Crohn’s disease and ulcerative colitis biochemical and nutrient issue. Academy of Nutrition and Dietetics, Nutrition Care Manual. 2012. Available at: http://www. nutritioncaremanual.org/content.cfm?ncm_content_id=91939. Access February 1, 2013. Sylvester FA, et al. Natural history of bone metabolism and bone mineral density in children with inflammatory bowel disease. Inflamm Bowel Dis. 2007; 13: 42. Dietary supplement fact sheet: iron. Office of Dietary Supplements-National Institutes of Health. 2012. Available at: http://ods.od.nih.gov/factsheets/Iron-HealthProfessional/. Accessed February 15, 2013. Link between low zinc and Crohn’s disease symptoms studied. Baylor College of Medicine. 2004. Available at: http://www.bcm.edu/cnrc/consumer/archives/zinc-chrons.htm. Accessed February 1, 2013.