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.