When people have weight loss surgery, their bodies can’t absorb nutrients as well as before. Researchers in India studied 32 patients after surgery to see if they were taking their vitamin supplements and whether it helped. Most patients took their iron supplements, but many skipped their protein and B12 supplements. The good news? The recommended supplements worked well at keeping nutrient levels healthy—but only if patients actually took them, especially for B12. This research shows that following your doctor’s supplement plan after weight loss surgery is important for staying healthy.

The Quick Take

  • What they studied: Whether patients who had weight loss surgery were taking their prescribed vitamins and minerals, and whether taking them actually prevented nutrient deficiencies.
  • Who participated: 32 patients in India who had weight loss surgery between August 2022 and July 2023. About two-thirds had one type of surgery (sleeve gastrectomy) and one-third had another type (gastric bypass).
  • Key finding: Patients who took their B12 supplements as prescribed had zero deficiencies, while those who didn’t take them had a 50% deficiency rate. For other nutrients like iron and calcium, deficiencies improved even if patients weren’t perfectly compliant with supplements.
  • What it means for you: If you’ve had weight loss surgery, taking your B12 supplements consistently is crucial—it makes a real difference in preventing serious deficiencies. Other supplements help too, but B12 seems to be the most important one to not skip.

The Research Details

Researchers followed 32 patients in India who had weight loss surgery over a 6-month period. They checked patients’ blood work before surgery and again after 6 months to measure levels of important nutrients like iron, B12, calcium, and vitamin D. All patients received the same supplement plan recommended by major surgery organizations. The researchers tracked whether patients actually took their supplements—they counted someone as “compliant” if they took at least 80% of their prescribed doses. This is called a prospective observational study, which means researchers watched what happened to patients over time without randomly assigning them to different groups.

This type of study is important because it shows what really happens in everyday medical practice in India, where weight loss surgery is becoming more common but there’s limited research on how well patients follow supplement recommendations. By tracking actual patient behavior and blood work results, researchers can identify which supplements matter most and which ones patients struggle to take consistently.

This study has some strengths: it measured actual blood nutrient levels rather than just asking patients what they took, and it followed patients for a meaningful 6-month period. However, it’s a relatively small study with only 32 patients at one hospital, so the results may not apply to everyone. The study was observational rather than experimental, meaning researchers couldn’t prove that supplements caused the improvements—only that they were associated with better outcomes.

What the Results Show

Over 6 months, patients’ weight significantly decreased, with their BMI dropping from 47 to 36.1 on average. However, patients’ compliance with taking supplements varied widely. Nearly all patients (96.9%) took their iron supplements regularly, but only 28.1% consistently took their protein supplements and 43.7% took their B12 supplements. The most striking finding involved B12: patients who didn’t take their B12 supplements had a 50% deficiency rate, while those who took them had zero deficiencies—a statistically significant difference. For other nutrients like iron, calcium, and vitamin D, deficiency rates improved after surgery regardless of whether patients perfectly followed their supplement plan, suggesting the body’s natural recovery and the supplements together helped maintain adequate levels.

Protein supplementation had the lowest compliance rate at only 28.1%, which is concerning since protein is essential for healing after surgery. Despite this low compliance, the study didn’t report specific protein deficiency rates, suggesting this may need further investigation. The study also found that the recommended supplement regimen from major surgery guidelines appeared adequate for most nutrients, indicating that the prescribed doses were appropriate for this patient population.

Previous research has shown that nutrient deficiencies are common after weight loss surgery, particularly for B12, iron, and calcium. This study confirms those findings but adds important new information: it shows that in India specifically, compliance with supplements is variable, and that B12 supplementation compliance directly impacts whether patients develop deficiencies. The finding that other nutrients improved despite lower compliance rates suggests that either the surgery itself promotes some nutrient recovery, or that even partial compliance helps prevent deficiencies.

The study included only 32 patients at a single hospital in India, so results may not apply to other countries or populations. The researchers didn’t randomly assign patients to take supplements or not—they just observed what happened—so they can’t prove supplements caused the improvements. The study didn’t deeply investigate why patients skipped certain supplements like protein and B12, which would help doctors improve compliance. Additionally, 6 months is a relatively short follow-up period; longer-term studies would show if these patterns continue.

The Bottom Line

If you’ve had weight loss surgery, take your B12 supplements consistently as prescribed—this is high confidence based on this research. Take your other prescribed supplements (iron, calcium, vitamin D, protein) as directed, though the research suggests some flexibility may be possible for nutrients other than B12. Have your blood work checked regularly as your doctor recommends to catch any deficiencies early. Moderate confidence: work with a nutritionist familiar with post-surgery care to understand why you might be skipping supplements and find solutions (like different forms or timing).

This research is most relevant for people who have had or are planning to have weight loss surgery, their family members, and their healthcare providers. It’s particularly important for people in India and similar healthcare settings. People considering weight loss surgery should understand that consistent supplement use is part of the commitment. This doesn’t apply to people who haven’t had weight loss surgery, as their nutrient absorption is different.

B12 deficiency can develop within months if you don’t take supplements, as shown by the 50% deficiency rate in non-compliant patients at 6 months. Other nutrient deficiencies may develop more slowly. You should expect to take supplements for life after weight loss surgery, not just for a few months. Blood work improvements may be visible within 3-6 months if you’re compliant with supplements.

Want to Apply This Research?

  • Set daily reminders for B12 supplement intake and track completion daily. Use a simple yes/no checklist in the app to mark each day you took your B12 supplement. Aim for at least 80% compliance (6 out of 7 days per week). Review your compliance percentage weekly.
  • Use the app to set up a daily alarm at the same time each day for your B12 supplement. Link it to an existing habit (like breakfast or brushing teeth) to make it automatic. If you’re struggling with compliance, use the app to log barriers (taste, side effects, forgetting) and share these with your doctor to find alternative formulations.
  • Track supplement compliance monthly and correlate it with your scheduled blood work results. Use the app to record your lab values for B12, iron, calcium, and vitamin D when you get them. Over time, you’ll see the connection between your compliance and your nutrient levels, which can motivate you to stay consistent.

This research describes findings from a small study of 32 patients in India and should not replace personalized medical advice from your healthcare provider. Weight loss surgery affects each person differently, and your specific nutritional needs depend on your surgery type, overall health, and individual factors. Always follow your surgeon’s and nutritionist’s recommendations for supplements and blood work monitoring. If you experience symptoms of nutrient deficiency (fatigue, weakness, numbness, or hair loss), contact your doctor immediately rather than relying on this information. This article is for educational purposes and does not constitute medical advice.