Table 1.

Causes of malnutrition in patients with IBD [7–9, 11–14].

Decrease in oral intake	(i) Restrictive diets (ii) Therapeutic fasting (iii) By the disease itself due to diarrhea, abdominal pain, nausea, and vomiting [9] (iv) Alteration in taste due to drugs, vitamin and mineral deficiencies, and proinflammatory mediators [7] (v) Anorexigenous effect of proinflammatory cytokines [7]
Gastrointestinal losses	(i) Diarrhea (ii) Rectorrhagia/hematochezia (iii) Loss of mucus and electrolytes (iv) Protein-losing enteropathy
Metabolic disorders	(i) Increase in resting energy expenditure due to inflammation, fever, and sepsis (ii) Enhanced fat oxidation
Increase in nutritional requirements	(i) Inflammatory states [7] (ii) Increased basal oxidative metabolism (iii) Infectious complications (iv) Postsurgery
Drug interaction	(i) Corticosteroids and calcium reabsorption (ii) Corticosteroids and protein catabolism (iii) Salazopyrin and folates [11] (iv) Methotrexate and folates [11] (v) Cholestyramine and liposoluble vitamins [11] (vi) Antimicrobials and vitamin K [12, 13] (vii) Antisecretors and iron [14]
Poor absorption of nutrients	(i) Reduction of the absorptive surface due to intestinal resection and enteric fistulas [8] (ii) Blind loops and bacterial overgrowth (iii) Poor absorption of bile salts in ileitis or resection [8] (iv) Mucosal inflammation