Vitamin Deficiency in gastric bypass/duodenalswitch-BPD

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Gastric bypass surgery bypasses the section of small bowel in which most vitamins are digested and absorbed.  Also, as seen below in the excerpts taken from various medical sources, that stapling the stomach into a smaller size or removing or bypassing part of the stomach can have repercussions as far as vitamin digestion. (for example - the gastric sleeve)

"All of the operations, old and new, are based on an incorrect assumption: that the stomach is no more than a passive sac for receiving food. In fact, it is a critical digestive organ and cannot be cut away or bypassed without compromising the digestive process." Paul Ernsberger, PhD, Department of Nutrition,
Case Western Reserve School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106-4906

Vitamin A

Secondary vitamin A deficiency may be due to inadequate conversion of carotene to vitamin A or to interference with absorption, storage, or transport of vitamin A. Interference with absorption or storage is likely in celiac disease, sprue, cystic fibrosis, pancreatic disease, duodenal bypass, (gastric bypass bypasses the duodenum and duodenal switch mostly bypasses the duodenum or first section of small bowel) congenital partial obstruction of the jejunum, obstruction of the bile ducts, giardiasis, and cirrhosis. Vitamin A deficiency is common in protein-energy malnutrition (marasmus or kwashiorkor), principally because the diet is deficient but also because vitamin A storage and transport are defective.

Inadequate intake or utilization of vitamin A can cause impaired dark adaptation and night blindness; xerosis of the conjunctiva and cornea; xerophthalmia and keratomalacia; keratinization of lung, GI tract, and urinary tract epithelia; increased susceptibility to infections; and sometimes death. Follicular hyperkeratosis of the skin is common.

The main function of vitamin D hormone is to increase calcium absorption from the intestine and promote normal bone formation and mineralization.


Calcium in the body must be tightly controlled because it is necessary to cell function for such things as blood clotting, muscle contraction, enzyme reactions, cellular communication and skin differentiation. It also gives bones and teeth their strength. In fact, the hardest substance in the human body, tooth enamel, is 95% calcium.  The calcium deficiencies in gastric bypass patients, is caused by the bypassing of the first part of the small bowel, called the duodenum.

In adults, demineralization (osteomalacia) occurs, particularly in the spine, pelvis, and lower extremities; the fibrous lamellae become visible on x-rays, and incomplete ribbonlike areas of demineralization (pseudofractures, Looser's lines, Milkman's syndrome) appear in the cortex. As the bones soften, weight may cause bowing of the long bones, vertical shortening of the vertebrae, and flattening of the pelvic bones, which narrows the pelvic outlet.

Abetalipoproteinemia (Bassen-Kornzweig syndrome), due to the genetic absence of apolipoprotein B, causes serious fat malabsorption and steatorrhea, with progressive neuropathy and retinopathy in the first two decades of life (see Abetalipoproteinemia in Medline). Plasma vitamin E levels are usually undetectable.

Symptoms and signs are caused by hypoprothrombinemia and related depression of other vitamin K-dependent coagulation factors. Bleeding is the major manifestation whether the cause is inadequate dietary intake or antagonism of vitamin K by drugs. Easy bruisability and mucosal bleeding (especially epistaxis, GI hemorrhage, menorrhagia, and hematuria) occur in vitamin K deficiency. Oozing of blood from puncture sites or incisions may occur after trauma, and life-threatening intracranial hemorrhage can occur in infants. In obstructive jaundice, hemorrhage--if it occurs--usually begins after the 4th to 5th day. It may begin as a slow ooze from a surgical wound, the gums, the nose, or GI mucosa, or it may be massive into the GI tract.

Calcium Deficiency from the Merck Manual

Vitamin B12 (gastric bypass patients should take shots at least once a week or better yet, daily)

  • Mechanisms of B12 deficiency
    • Reduced intrinsic factor production 2 parietal cell loss
    • Antibodies to B12 binding site on intrinsic factor: Prevent formation of complex that is normally carried to terminal ileum & absorbed
  • Associated immune disorders: Thyroiditis; Diabetes; Addison's; Ovarian failure; 1 hypoparathyroidism; Graves; Vitiligo; Myasthenia gravis; Lambert-Eaton syndrome; Common variable immunodeficiency with low Ig or IgA (younger patients)

Vitamin E deficiency

  • Vitamin E
    • Mixture of tocopherols
    • a-tocopherol most potent
    • Antioxidant
      • Prevents peroxidation of polyunsaturated membrane fatty acids
      • ? Relationship with vitamin E
    • Recommended daily allowance: Males 10 mg; Females 8 mg
    • Absorbed & incorporated into chylomicrons in small intestine
  • Causes of deficiency
    • Transfer protein disorders
      • A-b-lipoproteinemia
      • Vitamin E transporter deficiency
    • Malabsorption
      • Chronic cholestasis
      • Cystic fibrosis
      • Chronic bowel disease: Celiac; Whipple's; Inflammatory; Tropical sprue; Chronic pancreatitis
      • Surgical: Post gastrectomy; Short bowel syndromes (i.e. gastric bypass)
      • Chylomicron retention disease 
    • Reduced intake
      • Malnutrition
      • Total parenteral nutrition: May be associated with selenium deficiency
  • Clinical
    • Polyneuropathy
      • Sensory loss
        • Large fiber modalities
        • Sensory ataxia
      • Tendon reflexes: Absent
      • Electrodiagnostic
        • Sensory potentials: Usually small; May be normal
        • Abnormal somatosensory evoked potentials
    • Myopathy: 1 patient
      • Related to high dose cholestyramine treatment
      • Weakness: Generalized
      • Serum CK: High
      • Muscle pathology: Small ovoid inclusions (H&E purple; GT pink; Acid phos +)
    • CNS
      • Ophthalmoplegia
      • Spinal
        • Posterior column sensory loss
        • Extensor plantar responses
    • Systemic: A-b-lipoproteinemia
      • Retinitis pigmentosa
      • Acanthocytosis
  • Pathology
    • Dorsal root neurons: Early loss of distal region of central projection
    • Spinal cord: Loss of fibers in posterior & Clarke column
    • Axonal dystrophy (swellings) in cuneate & gracile nuclei
  • Diagnosis
    • Vitamin E levels: Undetectable or very low levels in serum
    • Other: Fat malabsorption Fatty stools; Low serum carotene
  • Treatment: Vitamin E supplementation
    • A-b-lipoproteinemia: 100 to 200 mg/kg/day in childhood ? + vitamins A & K
    • Malabsorption: 1 to 4 g/day

Vitamin D deficiency

  • Function
    • Steroid hormone
    • Active form: 1,25-dihydroxy vitamin D3 (Calcitriol)
    • Action via intracellular receptor
    • Regulates Ca++ & Phosphorus homeostasis
  • Clinical: Similar to hypoparathyroidism
    • Epidemiology: Dietary deficiency more common in
      • Northern Europe & US
      • Elderly patients
      • Immigrant populations
      • Infants: Vitamin D deficiency rickets
    • Myopathy (50%)
      • Weakness: Proximal; Symmetric
      • Muscle wasting
      • Myalgia
      • Muscle physiology
        • Reduced Force generation
        • Delayed relaxation
      • Tendon reflexes: Normal
    • Osteomalacia: See Osteomalacia in Medline
    • Treatment
      • Ergocalciferol: Oral (50,000 U 1x/week x6) or IM
      • Improvement in strength & reduced pain over weeks
  • Laboratory
    • 25-Hydroxyvitamin D reduced
    • Parathyroid hormone increased
    • Alkaline phosphatase: Often increased
    • Serum CK: Often normal
    • Muscle biopsy: Normal or Non-specific changes
  • Vitamin D malabsorption: Causes
    • Dietary deficiency
    • Reduced Sun exposure
    • Malabsorption: Post-surgical; Small Bowel disease (for example: gastric bypass)
    • Renal: Tubular acidosis; Chronic failure
    • Anticonvulsants

Postgastroplasty syndrome: Polyneuropathy +

  • Epidemiology
    • Surgery: For morbid obesity
    • Frequency of neuropathy: 5% of Gastric bypass surgeries
  • Associated with
    • Surgical procedures
      • Gastrojejunectomy  (BPD)
      • Gastric stapling (gastric bypass)
      • Gastroplasty
      • Gastrectomy
    • Vomiting
      • Severe protracted
      • May be chronic after gastrectomy (68%)
    • Weight loss
      • Degree: Mean 28%; Range 11% to 48%
      • Rapid
  • Polyneuropathy
    • Onset
      • Acute or Subacute
      • Numbness & paresthesias: Distal then proximal in legs
    • Sensory loss
      • Distal Proximal
      • Modalities
        • Large fiber: Joint position & Vibration
        • Small fiber
      • May simulate myelopathic pattern
    • Pain: Less prominent than in nutritional (Cuban) neuropathy
    • Weakness
      • Distal or Proximal
      • Legs > Arms
    • Hyporeflexia (66%)
    • Autonomic: Uncommon
      • Hyoptension: Syncope
    • Progression: May develop quadriparesis
  • CNS
    • Wernicke-Korsakoff like disorder
      • Confusion
      • Memory loss
      • Eye movement disorders
    • Affective disorders
    • D-lactate disorder: Bacterial overgrowth
  • Electrophysiology
    • EMG: Denervation
    • Nerve conduction studies
      • Axonal loss
      • Sensory + Motor involvement
  • Muscle biopsy
    • Type 2 muscle fiber atrophy
    • Denervation: Angular muscle fibers
  • Treatment
    • Parenteral nutrition
    • Vitamins: Thiamine +
  • Prognosis
    • Death 8%
    • Good resolution of signs 35%

Selenium Deficiency  (it is suspected - Mason et al - that gastric bypass patients can not digest and absorb the micronutrients like selenium, chromium etc)

In the U.S., most cases of selenium depletion or deficiency are associated with severe gastrointestinal problems, such as Crohn's disease, or with surgical removal of part of the stomach. (NIH faq sheet on Selenium Deficiency)

  • Selenium
    • Trace essential element
    • Sources: Meat; Fish; Cereals
    • Component of selenoproteins: Glutathione peroxidases; Iodothyronine 5'-deiodinases
    • Deficiency produces
      • Glutathione peroxidase activity: Reduced
      • Oxidative damage
  • Deficiency syndromes
    • Myopathy: Long term parenteral nutrition; Chronic bowel disease or removal of part of the stomach; Other dietary deficiency
    • Epidemic cardiomyopathy
      • 2 Reduced dietary selenium in pregnant women & children in Keshan, China
    • Animal disorders
      • "White muscle" or "Yellow fat" disease in horses & cattle
      • Probably related to concurrent selenium & vitamin E deficiency
  • Myopathy
    • Clinical
      • Muscle pain: Proximal
      • Weakness: Proximal, Symmetric
      • Treatment: Normal oral diet
    • Laboratory
      • Serum CK: High
      • Serum selenium: Low
      • Vitamin E levels: Commonly low
      • Muscle biopsy
        • Muscle fiber atrophy
        • Vacuoles
        • Thinned myofibrils
        • Mitochondria: Enlargement; Reduced Number
  • Cardiac disease: Arrhythmia; Cardiac failure

Thiamin (vitamin B1 deficiency)

Early deficiency produces fatigue, irritation, poor memory, sleep disturbances, precordial pain, anorexia, abdominal discomfort, and constipation.

The syndrome of peripheral neurologic changes due to thiamine deficiency is called dry beriberi. These changes are bilateral and symmetric, involving predominantly the lower extremities, and begin with paresthesias of the toes, burning of the feet (particularly severe at night), muscle cramps in the calves, and pains in the legs. Calf muscle tenderness, difficulty in rising from a squatting position, a decrease in the vibratory sensation in the toes, and plantar dysesthesia are early signs. A diagnosis of mild peripheral neuropathy can be made when ankle jerks are absent. Continued deficiency causes loss of knee jerk, loss of vibratory and position sensation in the toes, atrophy of the calf and thigh muscles, and finally footdrop and toedrop. The arms may be affected after leg signs are well established.

Cerebral beriberi (Wernicke-Korsakoff syndrome) results from severe acute deficiency superimposed on chronic deficiency (see Amnesias in Ch. 169). Mental confusion, aphonia, and confabulation constitute the early stage, called Wernicke's encephalopathy. Cerebral blood flow is markedly reduced and vascular resistance increased. Korsakoff's psychosis (Korsakoff's amnestic syndrome) consists of nystagmus, total ophthalmoplegia, coma, and, if untreated, death.

Cardiovascular (wet) beriberi (Shoshin beriberi) occurs in thiamine deficiency when myocardial disease is prominent. This causes a high cardiac output with vasodilation and warm extremities. Before heart failure occurs, tachycardia, a wide pulse pressure, sweating, warm skin, and lactic acidosis develop. With heart failure, orthopnea and pulmonary and peripheral edema occur; vasodilation continues, sometimes resulting in shock.

Merck Manual - Wernicke's encephalopathy/Korsakoff's psychosis


Structural and functional changes due to the total lack of intake of energy and essential nutrients.

Starvation is the most severe form of malnutrition. It may result from fasting, famine, anorexia nervosa, catastrophic disease of the GI tract, stroke, or coma. The basic metabolic response to starvation is conservation of energy and body tissues. However, the body will mobilize its own tissues as a source of energy, which results in the destruction of visceral organs and muscle and in extreme shrinkage of adipose tissue. Total starvation is fatal in 8 to 12 wk.

Symptoms and Signs

In adult volunteers who fasted for 30 to 40 days, weight loss was marked (25% of initial weight), metabolic rate decreased, and the rate and amount of tissue protein breakdown decreased by about 30%. In more prolonged starvation, weight loss may reach 50% in adults and possibly more in children. Loss of organ weight is greatest in the liver and intestine, moderate in the heart and kidneys, and least in the nervous system. Emaciation is most obvious in areas where prominent fat depots normally exist. Muscle mass shrinks and bones protrude. The skin becomes thin, dry, inelastic, pale, and cold. The hair is dry and sparse and falls out easily.

Most body systems are affected. Achlorhydria and diarrhea are common. Heart size and cardiac output are reduced; the pulse slows and blood pressure falls. Respiratory rate and vital capacity decrease. The main endocrine disturbance is gonadal atrophy with loss of libido in men and women and amenorrhea in women. Intellect remains clear, but apathy and irritability are common. The patient feels weak. Work capacity is diminished because of muscle destruction and, eventually, is worsened by cardiorespiratory failure. The anemia is usually mild, normochromic, and normocytic. Reduction in body temperature frequently contributes to death. In famine edema, serum proteins are usually normal, but loss of fat and muscle results in increased extracellular water, low tissue tension, and inelastic skin. Cell-mediated immunity is compromised, and wound healing is impaired (see Malnutrition-related Immunodeficiency ).

Heat and cold receptors are located in the skin. When the body temperature rises, the hypothalamus sends a nerve signal to the sweat-producing skin glands, causing them to release about 1-2 liters of water per hour, cooling the body. The hypothalamus also causes dilation of the blood vessels of the skin, allowing more blood to flow into those areas, causing heat to be convected away from the skin surface. When body temperature falls, the sweat glands constrict and sweat production decreases. If the body temperature continues to fall, the body will engage in thermiogenesis, or heat generation, by raising the body's metabolic rate and by shivering.

Iron deficiency generally occurs during the growth period or when intake fails to replace iron loss that is associated with blood loss. When iron stores are depleted and there is inadequate production of heme (the portion of hemoglobin associated with the iron), the red blood cells become small (microcytic) and have decreased capacity to carry oxygen. There is also a drop in iron-containing enzymes that are important in cellular metabolism. This results in decreased work capacity, fatigue and altered behavior such as irritability.


Iron is important in the transportation of oxygen from the lungs by way of the blood stream to the tissues. It is present in the red blood cell protein, hemoglobin. A similar protein in muscle, myoglobin, also contains iron and stores oxygen for use during muscle contraction. Iron is found in the portion of the cell involved in energy production and as a cofactor for several enzymes. Iron is stored in organs like the liver so the body depletes those areas first.  Anemia in long term gastric bypass patients is common - especially those with long limb intestinal bypass (like DS/BPD and distal gastric bypass).  It is remedied by regular iron infusions, an outpatient procedure.

Iron deficiency generally occurs during the growth period or when intake fails to replace iron loss that is associated with blood loss. When iron stores are depleted and there is inadequate production of heme (the portion of hemoglobin associated with the iron), the red blood cells become small (microcytic) and have decreased capacity to carry oxygen. There is also a drop in iron-containing enzymes that are important in cellular metabolism. This results in decreased work capacity, fatigue and altered behavior such as irritability.