After weight loss surgery, patients often need extra vitamins and minerals because their bodies can’t absorb nutrients as well. This study looked at 313 people who had two types of weight loss surgery and tracked their vitamin levels for 3 years. Instead of giving everyone the same large pile of supplements, doctors tested their blood and only added extra vitamins when needed. This personalized approach worked just as well as the standard approach but meant people took fewer pills. The most common problem was hair loss, and bone health needed careful watching, especially after one type of surgery.
The Quick Take
- What they studied: Whether doctors can use blood test results to decide which vitamins patients really need after weight loss surgery, instead of giving everyone the same supplements
- Who participated: 313 people (mostly women, average age 44) who had one of two common types of weight loss surgery at a hospital in France. Researchers followed them for 3 years and checked their blood regularly
- Key finding: When doctors only added extra vitamins based on blood test results, patients took fewer pills but had the same number of vitamin deficiencies as people who took standard supplements. More people needed extra supplements after one type of surgery (59%) than the other (43%)
- What it means for you: If you have weight loss surgery, your doctor may be able to give you a personalized vitamin plan based on your blood work instead of a one-size-fits-all approach. This could mean taking fewer pills while staying healthy, though you’ll need regular blood tests to monitor your levels
The Research Details
Researchers followed 313 patients who had weight loss surgery at a French hospital. They checked everyone’s vitamin and mineral levels before surgery and then at 6 months, 1 year, and 3 years after surgery. Everyone started with a standard multivitamin, but doctors added extra supplements only when blood tests showed deficiencies. The study compared two popular types of weight loss surgery: Roux-en-Y gastric bypass (where the stomach is made smaller and part of the intestines are rerouted) and sleeve gastrectomy (where part of the stomach is removed). Researchers tracked how many people needed extra supplements, what symptoms they experienced, and how many vitamin deficiencies they developed.
Weight loss surgery changes how the body absorbs nutrients, so doctors need to know the best way to prevent deficiencies. Previous approaches gave everyone the same supplements, but this created two problems: people had to take many pills (which many didn’t do), and some people might have been taking unnecessary supplements. This study tested whether using blood tests to personalize supplement plans could work better.
This study followed patients for a full 3 years with regular blood tests, which is strong evidence. The hospital kept detailed records and used a standardized protocol for deciding when to add supplements. However, this was a single-center study (one hospital), so results might differ in other places. The study didn’t randomly assign people to different treatment groups, so we can’t be completely certain the personalized approach caused the good results.
What the Results Show
The personalized supplement strategy worked well. Even though fewer people took extra supplements after sleeve gastrectomy (43%) compared to gastric bypass (59%), both groups had similar numbers of vitamin deficiencies at 3 years (3.7 deficiencies for bypass patients vs 3.4 for sleeve patients). This suggests that the personalized approach—only adding supplements when blood tests showed problems—prevented deficiencies just as effectively as giving everyone extra supplements. The most common symptom patients experienced was hair loss, which happened in both groups. Interestingly, serious problems like nerve damage were rare and mild when they did occur. Anemia (low red blood cells) was uncommon in both groups.
One important difference between the two surgery types emerged: patients who had gastric bypass were much more likely to develop secondary hyperparathyroidism (a bone-related condition affecting 23% of bypass patients vs 9% of sleeve patients). This condition happens when the body can’t absorb calcium properly and the parathyroid glands work overtime to compensate. This finding suggests that bypass patients may need more careful monitoring of their bone health and calcium levels.
Previous research recommended that all weight loss surgery patients take the same standard supplements, but many patients didn’t follow this advice because taking so many pills was inconvenient. This study supports a newer idea: that personalizing supplements based on individual blood test results could work just as well while reducing the pill burden. The findings align with growing evidence that one-size-fits-all approaches don’t work well for nutrition after surgery.
This study was conducted at one hospital in France, so results might be different in other countries or healthcare settings. The study didn’t randomly assign people to different supplement strategies, so we can’t be completely certain the personalized approach caused the good outcomes. The study didn’t measure how well patients actually took their supplements (compliance), which could affect the results. Additionally, the study didn’t compare costs, so we don’t know if the personalized approach saves money overall.
The Bottom Line
If you’re having weight loss surgery, ask your doctor about a personalized supplement plan based on blood tests rather than taking a standard set of supplements. This approach appears to work well and may mean taking fewer pills. However, you’ll need regular blood tests (at least at 6 months, 1 year, and 3 years) to monitor your levels. Pay special attention to bone health and calcium intake, especially if you’re having gastric bypass surgery. Watch for hair loss and report any unusual symptoms to your doctor. Confidence level: Moderate—this approach works well in this study, but more research in different settings would strengthen the evidence.
This research is most relevant for people planning to have weight loss surgery or those who recently had it. It’s particularly important for people having gastric bypass surgery, who appear to need more careful monitoring. Your doctor should help determine if this personalized approach is right for you based on your specific surgery type and health situation. People who have had other types of surgery or those with certain medical conditions may need different approaches.
You should expect to see the benefits of a personalized supplement plan over months and years, not days or weeks. Blood tests at 6 months will show if your initial supplement plan is working. By 1 year, you’ll have a clearer picture of which supplements you truly need. The study followed people for 3 years, suggesting that long-term monitoring is important for maintaining good nutrition after weight loss surgery.
Want to Apply This Research?
- Track your supplement intake daily and log any symptoms like hair loss, fatigue, or unusual sensations. Record the dates of your blood tests and the results for key nutrients (B12, iron, calcium, vitamin D, and parathyroid hormone). This creates a personal record to share with your doctor.
- Set up a daily reminder to take only the supplements your doctor prescribed based on your latest blood work, rather than taking a large handful of pills. Use the app to note which supplements you’re taking and when, making it easier to discuss compliance with your healthcare provider at appointments.
- Schedule and track blood test appointments every 6 months for the first 2 years after surgery, then annually. Log results in the app and watch for patterns—for example, if your B12 levels drop consistently, you may need ongoing supplementation. Set alerts for symptoms to report at your next doctor visit, especially bone-related symptoms or neurological changes.
This research describes one approach to managing nutrition after weight loss surgery, but it should not replace personalized medical advice from your doctor or surgeon. Weight loss surgery affects everyone differently, and your specific nutritional needs depend on your surgery type, overall health, and individual circumstances. Always follow your healthcare provider’s recommendations for supplements and blood testing. If you experience symptoms like severe fatigue, numbness, or bone pain, contact your doctor immediately. This information is for educational purposes and should be discussed with your medical team before making any changes to your supplement routine.