Bariatric surgery is performed when obesity cannot be treated by diet control or exercise. In bariatric surgery, they remove or alter a part of the gut to reduce the quantity of food you can eat or the way your body absorbs food, resulting in weight loss.  

Importance of nutrition and vitamin supplements after surgery 

After the surgery, you can’t eat anything for a month or two. Your digestive system is altered in the surgery, which affects your body and the way it absorbs its nutrients. All you can consume is a carefully selected liquid/pureed diet, which cannot fulfill all requirements in terms of nutrition and vitamins. Long-term health risks associated with weight-loss surgery include:  

  • Anemia caused by iron/ vitamin B12 deficiency 
  • Neurological issues like Memory loss or irritability caused by a lack of B12  
  • Bone and kidney disease (due to changes in the way your body absorbs calcium and vitamin D).  

The doctor will recommend supplements to ensure proper nutrition, such as: 

  • Multivitamins 
  • Vitamin B12 
  • Calcium 
  • Iron  
  • Vitamin D 

These help you to achieve the nutrition requirements when you’re eating less. They are recommended to be taken in chewable or liquid form in the beginning, but after some time you can take them in pill form.   

Complete Multivitamins  

  • Vitamins need to be consumed in chewable or liquid form (usually with iron supplements) in the first month after the surgery. 
  • If you choose an over-the-counter multivitamin, take one serving in the morning and another at bedtime.  
  • Take only the dietitian/bariatrician-recommended multivitamins to fulfill your nutritional requirements.  

Vitamin B12 

  • Vitamin B12 helps to protect against memory loss, improves the immune system, and bolsters energy levels.  
  • You can consume it by putting it under the tongue (sublingual) or by injecting it. Ask your health care provider which method is best for you. 
  • If taken orally, the recommended dose is 500 micrograms of Vitamin B12. If you’re getting an injection of vitamin B12 once every month, you will need to visit the hospital as written in your prescription from your bariatrics team.   


  • Calcium is necessary for healthy bones, muscles, and nerve functioning.  
  • The daily calcium needs vary from 1200-1500 milligrams per day after having a gastrectomy or Roux-en-Y gastric bypass. After a duodenal switch, you need 1800-2400 milligrams per day of calcium.  
  • The calcium intake depends on how much calcium you are consuming in your routine diet. Your body can absorb 500-600 milligrams at one time.  
  • Calcium citrate is the form that’s recommended by most doctors. They should be taken after meals.  


  • Iron is very important for the body because it helps to make hemoglobin and hormones and carries oxygen to all parts of the body.  
  • If you have an iron deficiency you can feel dizziness, fatigue, light-heartedness, fast heart rate, or have brittle nails, etc.  
  • Its deficiency is commonly found in the US, even more, those who receive bariatric surgery.  
  • So, it is recommended that you consume 45-60 milligrams of iron in the form of sulfate, fumarate, or gluconate) per day. 
  • Do not take iron and calcium at the same time (separate the doses with at least 2 hours difference).  

Vitamin D 

  • Vitamin D helps control the amount of calcium and phosphate in our body and keeps our bones, teeth, and muscles healthy.  
  • You need 75 micrograms or 3000 international units of Vitamin D daily. 
  •  The best way to get Vitamin D is by taking sunlight.  
  • Add Vitamin D with calcium and multivitamin supplements to meet your daily requirements.  

After bariatric surgery, it becomes more essential to watch nutrition and diet because your body cannot digest vitamins and minerals with food like before. But if you’re taking supplements, you don’t need to worry about nutritional and vitamin deficiencies in the long run.  

Want more detailed information on weight loss and bariatrics? 

 Call us at 347-868-1060. 

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