Nutritional status and nutritional therapy in inflammatory bowel diseases

Table 1 Pathophysiology of malnutrition

Main mechanism	Effect
Decreased food intake	Anorexia
	Abdominal pain, nausea, vomiting
	Restricted diets
	Drugs
Nutrients malabsorption	Reduced absorptive surface due to inflammation, resection, bypass and fistulae
Increased intestinal loss	Exudative enteropathy (protein loss)
	Occult/overt blood loss (iron deficiency)
	Diarrhea (increased loss of Zn2+, K+, Mg2+)
	Steatorrhea (fat and fat soluble vitamin malabsorption, and divalent cations’ loss: Zn2+, Mg2+, Ca2+, Cu2+)
Hypermetabolic state	Alterations of resting energy expenditure
Drugs' interaction	Anorexia, nausea, test alteration, proteolysis, interaction with nutrients absorption/utilization

Table 2 Nutritional assessment in patients with IBD

Assessment	Parameters	Percentage of CD patients with deficient intake or parameters
Dietary history	Energy intake, low	40%[515]
	Protein intake, high	150% RDA[5]
	Carbohydrates, excess	39.2%[17]
	Fat, and saturated fat, excess	27%, and 59.5%[17]
	Iron intake, low	50%, 13%[18]
	Calcium and phosphor intake, low	23%[18]
	Folate intake, low	19%[18]
	Vitamin A intake, low	13%-21%, 26%[1819]
	Vitamin B intake, low	18%-37%[19]
	Vitamin C intake, low	21%-34%, 11%[1819]
	Vitamin D	36%[18]
	Vitamin E	63%[18]
Anthropometry	IBW < 90%	40%[5]
	BMI > 25 kg/m2	32%[15]
Body composition	Fat body mass, SFT < 15%	30%[5]
	Fat free mass, MAC < 15%	59%[5]
	DXA (dual-energy X-ray absorptiometry)	30% osteopenic, 60% sarcopenic[20]
	Nitrogen balance, negative	[21]

RDA: Recommended daily allowance; IBW: Ideal body weight; BMI: Body mass index; SFT: Skinfold thickness triceps; MAC: Mid arm circumference.

Table 3 Nutritional deficiencies in patients with IBD

Macro- and micro-nutrient deficiencies	Nutrients	Percentage of CD patients with deficiencies
Hypoproteinemia and hypoalbuminemia		17.6[18]
Anemia	Iron deficiency	39.2[18]
	B12 deficiency	18.4[18]
	Folic acid deficiency	19[18]
Electrolytes and trace elements	Zinc	15.2, 65[1819]
	Copper	84[19]
	Selenium	82[19]
Vitamins' deficiency (low serum levels)	B12 deficiency	18.4[18]
	Vitamin A	23.4[18]
	Vitamin B	29[18]
	Vitamin C	84[19]
	Vitamin D	17.6[18]
	Vitamin E	16[15]

Table 4 Pathophysiology of growth failure in children with IBD

Ethiopathogenesis	Mechanism
Energy and nutrient deficiencies[30]	Deficits of energy, macronutrients and micronutrients
Inflammation/proinflammatory cytokines[31]	Anorexigenic effect
	GH-IGF1 axis effects
	Bone metabolism disturbance
	Hypermetabolic/catabolic effects
Disease severity and disease location[3233]	Severe disease
	Jejunal localization
Abnormal bone metabolism[34]	Effect of pro-inflammatory cytokines
	GH-IGF1 axis dysfunction
	Calcium and vitamin D deficiency
	Delayed sexual maturation
	Corticosteroids
Delayed onset of sexual maturation[35]	Hypogonadism
Abnormal IGF1 axis[36]	Low IGF1 and IGF1-BP
	Proinflammatory cytokines
Drugs[28]	Corticosteroids

Table 5 The mechanism of action of enteral nutrition in CD

Proposed mechanism of action	Ref.
Improvement of nutritional status	[59]
Down regulation of pro-inflammatory cytokines	[6465]
Anti-inflammatory effects	[6162]
Promote epithelial healing	[6265]
Decrease gut permeability	[66]
Decrease antigenic load to the gut, bowel rest	[59]
Modification of gut flora	[67]