- WLS multivitamin designed for your type of operation.
- Calcium with vitamin D: at least 1,500 mg a day after a bypass.
- Multivitamin and calcium at least two hours apart.
- Not reimbursed: about €10-€15 a month.
- Diet: six small meals, half an hour between eating and drinking.
Which vitamins do you need after a gastric bypass?
Because of the rerouting you absorb fewer nutrients. Vitalys mainly mentions deficiencies of iron, vitamin B12 and folic acid, and to a lesser extent zinc, manganese, selenium and vitamins A, E and K. WLS supplements are developed specifically for people after weight loss surgery: the ratio of vitamins and minerals is adjusted and the tablet dissolves at the right place in the gut.
You also need calcium with vitamin D, because you no longer absorb enough of it from food. After a bypass that means at least 1,500 mg a day, spread over the day, for example three tablets. Too little calcium can lead to bone loss over time.
Can I buy gastric bypass vitamins at the drugstore?
Many people look for vitamins at the drugstore. A standard multivitamin is not sufficient after weight loss surgery, according to Vitalys; you need a WLS multivitamin suited to your operation. These are usually ordered online, for example from FitForMe or Vitamine op recept, the suppliers Vitalys mentions. Calcium with vitamin D can be bought at a pharmacy or drugstore, provided the dose is right. Order your WLS vitamins before the operation; hospitals advise trying a sample pack first.
Diet advice after a gastric bypass
Straight after the operation you start with clear fluids such as water and tea without sugar. Ziekenhuis Rivierenland starts the next day with small portions of liquid food, such as a 30 millilitre medicine cup of yoghurt, custard or apple sauce, and then builds up to puréed and solid food.
In the long term you eat six small meals a day and keep at least half an hour between eating and drinking, so food is not flushed through. Fasting is discouraged in the first year. Limit sugar and fat to prevent dumping, choose sour rather than sweet dairy, and chew well: food that is chewed too coarsely can get stuck.
What works and what goes wrong with vitamins
Advantages
| Advantage | Explanation |
|---|---|
| WLS multivitamin | dose adjusted to your operation |
| Taking it at night | advice from Vitalys |
| Sample pack | try what suits you first |
| Opening a capsule | with water or fruit purée if swallowing is hard |
Points of attention
| Point of attention | Explanation |
|---|---|
| Standard multivitamin | contains too little after surgery |
| Calcium and multivitamin together | keep at least two hours apart |
| Stopping when you feel well | deficiencies develop slowly |
| Pregnancy vitamins | too little for someone with a bypass |
Cost and insurance (2026)
Vitamins are not part of the covered pathway. They are a lifelong cost.
| Item | Amount or arrangement |
|---|---|
| WLS multivitamin plus calcium | about €10-€15 a month |
| Per year | about €120-€180 |
| Reimbursement | not from the basic package |
Vitamins after a gastric bypass: key figures
| Feature | Value |
|---|---|
| Calcium after bypass | at least 1,500 mg a day |
| Calcium after sleeve | at least 1,000 mg a day |
| Between multivitamin and calcium | at least 2 hours |
| Meals per day | 6 |
| Between eating and drinking | at least 30 minutes |
Supplements per operation
| Operation | Calcium with vitamin D | Multivitamin |
|---|---|---|
| Gastric bypass | at least 1,500 mg | WLS, for bypass |
| Mini gastric bypass | at least 1,500 mg | WLS, extra attention to A, D, E, K |
| Gastric sleeve | at least 1,000 mg | WLS, for sleeve |
| SADI | as prescribed by the centre | special SADI formula |
Step by step
- Before surgery. Order WLS vitamins, possibly a sample pack.
- Day 1. Clear fluids: water, tea without sugar.
- First weeks. Liquid, then puréed, then solid.
- Every day. Multivitamin and calcium, two hours apart.
- Every year. Blood tests for iron, B12, folic acid and vitamin D.
Read next
- Gastric bypass explained — the operation
- Gastric bypass disadvantages — honest overview
- Aftercare and blood tests — five years
- Recovery and food build-up — week by week
Vitamins when you live abroad or travel
Dutch WLS brands can usually be ordered online and shipped within Europe, but check delivery times before a long trip and take enough with you. If you move abroad, ask your centre which composition you use, so a local doctor can prescribe an equivalent product.
Keep taking calcium and the multivitamin two hours apart while travelling as well, and continue yearly blood tests with your new GP.
Frequently asked questions about vitamins and diet after a bypass
A WLS multivitamin designed for the bypass, plus at least 1,500 mg of calcium with vitamin D a day. You take them for life.
A standard multivitamin is not enough after weight loss surgery. You need a WLS multivitamin, usually ordered online. Calcium with vitamin D can be bought at a pharmacy or drugstore if the dose is right.
Vitalys mentions FitForMe and Vitamine op recept; you order online. Many suppliers offer a sample pack, so you can choose tablets, capsules or chewables.
No. Lifelong supplements are not reimbursed by Dutch health insurers. Expect about 10 to 15 euros a month.
Because they hinder each other's absorption. Keep at least two hours between them. Vitalys advises taking the multivitamin at night.
Deficiencies develop slowly, sometimes over months or years: anaemia from iron or B12 deficiency, hair loss and, in the long term, bone loss from too little calcium. Yearly blood tests detect this.
Six small meals a day, at least half an hour between eating and drinking, chewing well, and little sugar and fat to prevent dumping. No fasting in the first year.
On the day of surgery only clear fluids such as water and tea without sugar. From the next day small portions of liquid food, for example a 30 millilitre cup of yoghurt or apple sauce, as Ziekenhuis Rivierenland describes.
Sour dairy such as buttermilk, quark and yoghurt instead of sweet versions, two to three portions a day. Milk sugar is a fast sugar that can trigger dumping.
Keep using your WLS multivitamin and add 400 micrograms of folic acid from four weeks before conception until week ten, plus calcium. Do not switch to regular pregnancy vitamins; they contain too little.
Call +31 6 38048347 (Mon–Fri 09:00–17:00) or email info@maagverkleining-info.nl. This page is also available in Dutch.
Sources
- Vitalys (Rijnstate): FAQ, WLS supplements, calcium and pregnancy
- Ziekenhuis Rivierenland: patient information gastric bypass and sleeve
- St. Antonius and Amsterdam UMC: dairy after weight loss surgery
- WeightWorks: gastric bypass
Search terms leading here: vitamins after gastric bypass, WLS vitamins Netherlands, calcium after gastric bypass, gastric bypass diet advice.
Author: Gijs Bodenstaff. Last reviewed: September 2026.