Table 1 Common micronutrient deficiencies, their symptoms, and guidance for supplementation after biliopancreatic diversion

 Vitamin A

Night blindness

No corneal changes: 10,000–25,000 IU per day orally^c; corneal changes: 50,000–100,000 IU administered intramuscularly (3 days) followed by 50,000 IU intramuscularly (two weeks).

 Vitamin D

Osteoporosis, fractures

3000–6000 IU per day orally

 Vitamin E

Ataxia, loss of vibration or position sense, muscle weakness

Optimal therapeutic dose undefined

 Vitamin K

Coagulation disorder (bleeding or bruising)

1–2 mg per day orally in case of acute malabsorption or 1–2 mg per week intravenously in case of chronic malabsorption

 Vitamin B1 (thiamine)

Gastro-enterologic: nausea, vomiting; Wet beriberi: cardiovascular symptoms; Dry beriberi: neurological symptoms (Wernicke-Korsakov syndrome)

Orally: 100 mg (2–3x per day); Intravenously: 200 mg (3x per day) or 500 mg (1-2x per day) until symptoms resolve and consider oral therapy afterwards (100 mg); Intramuscularly: 250 mg (1x per day during 3–5 days) or 100–250 mg (1x per month).

 Vitamin B9 (folic acid)

Fatigue, anaemia, cognitive impairment, depression

1000 μg per day orally^d

 Vitamin B12 (cobalamin)

Neuropathy, muscle weakness, fatigue, anaemia, mood disorders

1000 μg orally or intramuscularly

 Iron

Fatigue, microcytic anaemia, hair loss, brittle nails, angular cheilosis

150–200 mg of elemental iron orally^e, in non-responders intravenous iron infusion should be considered

 Zinc

Diarrhoea, anaemia, hair loss, glossitis, hypogeusia, delayed wound healing, skin lesions and mental abnormalities

Optimal therapeutic dose undefined

 Copper

Painful neuropathy, anaemia, neutropenia, optic neuropathy, fatigue, iron deficiency

Mild to moderate deficiency: 3–8 mg per day orally; Severe: 2–4 mg per day intravenously