Additional information to support GPs is available from the BOMSS GP Hub.

All bariatric surgical procedures compromise nutrition to varying extent and have the potential to cause clinically significant deficiencies. Following bariatric surgery, patients require annual nutritional monitoring and routine nutritional supplements.

Micronutrient monitoring during the immediate post-operative period and for 2 years post-surgery falls under the remit of specialist follow-up. All patients should have been given a long-term management plan by the specialist centre, including guidance on vitamin, mineral and trace element supplementation. Patients will be required to stay on life-long nutritional supplements in addition to having a balanced diet and have life-long monitoring of their nutritional status.

The British Obesity and Metabolic Surgery Society (BOMSS) has issued post-bariatric surgery nutritional guidance for GPs which includes recommendations for annual blood monitoring and lifelong nutritional supplementation (see here). GPs requiring advice or support should contact the centre where the procedure was undertaken if possible; local specialist teams may also be able to provide advice.

See here for relevant formulary products:

• Forceval (A-Z multivitamin and mineral); see 9.6.7 Multivitamin preparations
  • See section below for appropriate formulation for patients who are planning pregnancy or who are pregnant
• Calcium and colecalciferol (vitamin D3); see 9.6.4 Vitamin D
• Iron; see 9.1.1 Iron deficiency anaemias
• Hydroxocobalamin (IM vitamin B12 injections); see 9.1.2 Drugs used in megaloblastic anaemias

It is accepted that patients post bariatric surgery may require non-formulary products and/or off-label doses. Specialists should be consulted for further advice.

If patients are intending to purchase their own products, they should follow guidance provided by their specialist centre.

Preconception and pregnancy

Seek specialist advice on nutritional supplementation for women who have undergone bariatric surgery and are planning to become pregnant or who are pregnant. Ongoing supplementation is required; however, requirements differ i.e. folic acid at a dose of 5mg per day, avoiding retinol (see below).

Women who become pregnant post-bariatric surgery need urgent referral for consultant-led care.

Women, as part of preconception care, are advised to avoid vitamin and mineral preparations which contain vitamin A in the retinol form in the first 12 weeks of pregnancy. Supplements containing retinol may increase the teratogenic risk especially in the first trimester. Prescribers should check that any supplements contain vitamin A in the beta carotene and not retinol form:

• Forceval capsules contain vitamin A in the beta carotene form and may be taken preconception and during pregnancy
• Forceval soluble tablets contain vitamin A in the retinol form and should not be taken preconception and during pregnancy.