Nutrition: Malnutrition & Obesity
(Gastroenterology 2002;123:879-81 & 882-32)
DEFINITIONS:
Nutritional status: reflects how well nutrient intake contributes to body composition and function in the face of existing metabolic needs
Four major components: water, protein, mineral, and fat; The first three compose the lean body mass (LBM)
Malnutrition: refers to states of overnutrition (obesity) or undernutrition relative to body requirements, resulting in dysfunction
Marasmus: protein-calorie undernutrition associated with physical wasting, but preservation of visceral and serum proteins
Hypoalbuminemic: malnutrition occurring with stressed metabolism and common in hospitalized patients
Body Mass Index (BMI) = wt (kg)/ht2 (m)
Normal: 18.5-24.9; Overweight: 25-29.9; Obesity: 30-39.9; Morbid Obesity: 40-49.9; Super obesity: >50
Obesity related comorbidities/diseases:
Cardiomyopathy, Coronary artery disease, Dyslipidemia, Hypertension, Diabetes, Infertility, Fatty Liver
GERD, Gallstones, Chronic fatigue, Urinary stress incontinence, Deep vein thrombosis/Pulmonary embolus/Venous stasis
Degenerative joint disease, Immobility, Depression, Malignancies, Dyspnea, Obstructive sleep apnea
Closer assessment if: poor intake for longer than 1-2 weeks; Weight loss of more than 10%; Weight less than 80% of desirable weight
Ideal body weight:
♂ = 106 lb for first 5′, plus 6 lb for each additional inch
♀ = 100 lb for first 5′, plus 5 lb for each additional inch
See also: Bowel- Short Bowel Syndrome (Chapter 2.23) and Eating disorders in Esophagus/Gastric-Potpourri (Chapter 1.24)
PATHOPHYSIOLOGY:
Intestinal epithelial cells are renewed and turned over every 48-72 hours
Absorption:
Iron and folate in Duodenum
Vitamin B12 and bile salts in Ileum
B12 from food is bound to R-protein in stomach; Pancreas enzyme cleave R-Protein in duodenum; B12 then binds to intrinsic factor
All others (carbohydrates, fats, proteins, calcium, magnesium, trace elements, vitamins, etc) throughout entire small bowel
Carbohydrates (Starch, Sucrose/Sugar, Lactose):
Starch requires amylase to convert to maltase; Maltase, Sucrase and Lactose are absorbed in the brush border of small bowel
Protein:
Require endo/exopeptidases from intestine and pancreas; Proteins are absorbed in the brush border of small bowel
Fat:
Requires pancreas (lipolysis), Liver (bile salts), Jejunal mucosa (absorption) and lymphatics for transport (Fats are not transported via portal system)Related posts:
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