Home / Diseases & Conditions / Vitamin and Micronutrient Deficiencies after Weight Loss Surgery
Vitamin and Micronutrient Deficiencies after Weight Loss Surgery
Weight loss (bariatric) surgery can be highly effective for weight loss and improving health, but it also changes how food is absorbed in the stomach and intestines. This can lead to deficiencies in important vitamins and minerals.
Why are vitamins and micronutrients important after weight loss surgery?
Without careful management, deficiencies can cause fatigue, anaemia, bone weakness, hair loss, and nerve or memory problems.
Lifelong attention to nutrition is therefore essential after bariatric surgery.
The most frequent deficiencies after weight loss surgery include:
Iron – low levels can cause anaemia, leading to tiredness, weakness, and shortness of breath.
Vitamin B12 – important for red blood cells and nerve function.
Folate – helps with red blood cell production and DNA repair.
Vitamin D and Calcium – essential for healthy bones and teeth.
Other micronutrients such as thiamine, zinc, selenium, and fat-soluble vitamins (A, E, K) may also be affected.
Your doctor and dietitian will monitor these with regular blood tests.
How are deficiencies managed?
Daily supplements - Most people will need to take lifelong multivitamin and mineral supplements after weight loss surgery. These usually include iron, B12, folate, vitamin D, calcium, and trace elements. Your doctor or dietitian will guide you on the correct type and dose.
Iron therapy - Some people cannot absorb enough iron from tablets after bariatric surgery. In this case, iron infusions (given directly into a vein) may be recommended to restore healthy iron levels.
Vitamin B12 - Because absorption of B12 is often reduced after surgery, regular B12 injections (every 1–3 months) or high-dose oral supplements are usually required.
Other infusions - Occasionally, vitamin infusions (such as vitamin D) may be needed if levels are very low and do not respond to tablets.
Regular blood tests are essential after bariatric surgery to detect deficiencies early. Your care team will adjust treatment based on your blood test results.
Care at Intus
With the right supplements, monitoring, and care, most vitamin and micronutrient deficiencies can be prevented or corrected. Lifelong follow-up is essential to stay healthy after bariatric surgery.
Your Intus team will support you with regular monitoring, timely treatment (such as iron infusions or vitamin injections), and personalised dietary advice.
You are not alone in this - together we will help you maintain your health and wellbeing long-term.
Our specialist team
Managing nutrition after weight loss surgery is a team effort. At Intus, your care team includes:
Specialist doctors – monitoring long-term health and prescribing treatment such as infusions or injections
Nurses – administering iron or vitamin infusions and providing ongoing support
Dietitians – guiding your nutrition, supplements, and food choices to minimise deficiency risk
This integrated approach helps protect your health and ensures you get the most benefit from bariatric surgery.
Find A Specialist
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Dr Nigel S. Rajaretnam
General, Oesophago-gastric & Endocrine Surgeon
