Vitamin and mineral supplements are a lifelong requirement after bariatric surgery. Non-compliance with supplementation can result in severe and sometimes irreversible complications. When patients see a healthcare professional, they should support them to continue taking their supplements.

Nutrients at most risk of malabsorption and associated problems:

  • Iron
  • Vitamin B12
  • Folate
  • Calcium
  • Vitamin D
  • Magnesium
  • Albumin

Recommended daily vitamin and mineral supplements:

Post gastric band:

  1. Over the counter multivitamin and mineral preparation e.g. Sanatogen A-Z, Centrum vitamin and mineral once a day. Forceval may be required following NHS prescription in established vitamin and mineral deficiencies as per clinical need.

Post sleeve gastrectomy

  1. Over the counter multivitamin and mineral preparations e.g. Sanatogen A-Z, Centrum advance twice a day, to be modified based on blood levels of vitamins and minerals. Forceval may be required following NHS prescription in established vitamin and mineral deficiencies as per clinical need.
  2. Maintenance oral dose of vitamin D 3000 IU per day OR 20,000 IU once per week in presence of normal vitamin D level.
  3. Recommend vitamin B12 injections 3 monthly. The frequency of vitamin B12 injections might need to be increased in established severe deficiency. Important note: In patients with both vitamin B12 and folate deficiency, folate supplements should not be given alone, as it can precipitate severe neurological complications (sub-acute combined degeneration of spinal cord).

Post gastric bypass:

  1. Over the counter multivitamin and mineral preparations e.g. Forceval, Centrum advance twice a day, to be modified based on blood levels of vitamins and minerals. Forceval may be required following NHS prescription in established vitamin and mineral deficiencies as per clinical need.
  2. Maintenance oral dose of vitamin D 3000 IU per day OR 20,000 IU once per week in presence of normal vitamin D level.
  3. Recommend vitamin B12 injections 3 monthly. The frequency of vitamin B12 injections might need to be increased in established severe deficiency. Important note: In patients with both vitamin B12 and folate deficiency, folate supplements should not be given alone, as it can precipitate severe neurological complications (sub-acute combined degeneration of spinal cord).

Vitamin D, calcium and magnesium

Severe vitamin D deficiency (<30nmol/L) - intramuscular vitamin D injection 300,000 IU followed by oral 20,000 IU colecalciferol two times a week until serum levels returned to normal. Then continue with a usual maintenance regimen of oral 20,000 IU colecalciferol once a week OR 3,000 IU colecalciferol daily. Before starting high doses of vitamin D, hypercalcaemia due to any other cause should be excluded.

Cautions with vitamin D
The total dose of vitamin D should be considered and adjusted accordingly with other medicinal products containing vitamin D. The calcium status and dietary intake of individual patients should also be considered at the same time as starting vitamin D3 replacement or treatment.

Impairment of renal function

  • monitor the effect on calcium and phosphate levels.
  • In severe renal insufficiency, vitamin D in the form of colecalciferol is not metabolised normally and other forms of vitamin D should be used.
  • Consider risk of soft tissue calcification.

Sarcoidosis or other granulomatous disease

  • Increased risk of metabolism of vitamin D to its active form.
  • Monitor calcium in serum and urine.

Primary hyperparathyroidism

  • Treatment with vitamin D may unmask this.
  • Monitor serum calcium in susceptible patients.
  • If calcium levels are raised then it is possible that vitamin D treatment has unmasked primary hyperparathyroidism and a referral should be made to a specialist e.g. endocrinologist if required.

Calcium supplements
Calcium citrate 1000mg per day is a preferred form of oral calcium supplement for patients with past history of calcium-containing kidney stones/other bariatric surgeries. It can be bought from online sources/local health shops as it is not currently available in NHS pharmacies.

Reducing the risk of kidney stones with high-risk patients on calcium supplements

  • Always take with food
  • Drink 2-2.5L water per day
  • Diet high in calcium, low in oxalate and low in salt

During long-term treatment, serum calcium levels and renal function (serum creatinine) should be monitored. Monitoring is especially important in elderly patients on concomitant treatment with cardiac glycosides or diuretics and in patients with an increased tendency to calculus formation. In the case of hypercalciuria (exceeding 300 mg (7.5 mmol)/24 hours) or signs of impaired renal function, the calcium dose should be reduced or the treatment discontinued.

Magnesium
Some patients might need magnesium supplements if they have symptomatic hypocalcaemia. Patients on high doses of vitamin D can have a depletion of tissue magnesium stores and therefore magnesium supplementation is recommended if patient clinically symptomatic or serum magnesium levels are low.

Iron

In cases of depleted iron stores or established iron deficiency anaemia (IDA), oral iron supplements may be required in addition to a patient's usual supplement plan. Some patients might require a higher than the regular therapeutic dose of iron for a short period to treat IDA and replenish iron stores, due to surgery-associated malabsorption, and should be monitored to prevent any iron toxicity. Consider referral to your local hospital for an iron infusion if clinically indicated and oral iron supplements are not sufficient to treat the condition.

Hints with iron supplements

  • Take with a small amount of orange juice (unless this causes dumping syndrome in the patient). (Vitamin C is known to increase iron absorption but should be used with caution as high doses of vitamin C are known to be associated with increased risk of oxalate-containing kidney stones).
  • Tea/coffee should be spaced 90minutes away from food and iron supplements.
  • Patients suffering from severe constipation or bloating on oral iron supplements should be tried on other formulations including liquid formulations (e.g. Feroglobin, Spatone). Sometimes a combination of liquid and tablet formulation might be better tolerated than high daily doses of iron tablets, to reach the appropriate dosage of iron.