Vitamins after weight loss surgery: what are the best vitamins to take after bariatric surgery?

Added by Klaudia Grabowska on 11.12.2020

Vitamins after weight loss surgery

Bariatric surgery is a life-changing moment in our lives. Once you decide to have it, you commit yourself to all the changes it entails. Of course, a special post-op diet and physical activity guarantee significant weight loss, but there are some other aspects of a post-op life that need to be mentioned. In this article, we will focus on Vitamins after weight loss surgery.

Generally, any bariatric surgery makes patients eat much less food, they need to follow a special diet for the first months (it is very restricted) and their stomach capacity is significantly reduced. Being able to eat so little, they still need to provide themselves enough nutrition. Proper nutrition consists of macroelements, microelements, and water. The post op diet is constructed in a way that patients drink enough water and eat enough macronutrients (proteins, fats, and carbs). Unfortunately, it is almost impossible to provide all the necessary micronutrients eating so little. 

Micronutrients, that is minerals and vitamins after bariatric surgery, are as important as water and macronutrients. Bariatric patients are advised to supplement them for the rest of their lives. Below, we will explain the importance of after bariatric surgery vitamins and minerals supplementation. 

Why is it important to take vitamins after weight loss surgery?

Smiling size plus lady in front of her computer

Patients after weight loss surgery must follow a new healthy diet, but it is also important to remember that they need to take vitamins, sometimes for the rest of their lives

Vitamins are present in food and eating healthy meals with many fruits and vegetables is the best way of getting vitamins and minerals. When we follow a healthy diet, there is usually no need to take additional supplements. The situation is different for bariatric patients. Why do we need to take vitamins after weight loss surgery? Well, the number of calories is greatly restricted and food absorption is changed, so there are products that must be avoided – the post-op diet is generally highly limited especially at the beginning, so it is impossible to get all the nutrients from food and vitamins levels after bariatric surgery are extremely low. 

The main role of vitamin and minerals is ensuring that the body functioning is proper, there are hundreds of vitamin roles – they eg. regulate metabolism and appetite, enable brain activity, protect thyroid function, give energy, maintain skin and hair condition.

Below, we present a full list of vitamins and minerals and their function in our bodies.



FOOD SOURCES (examples)

Vitamin A and Carotene

it is responsible for vision, lowers the risk of prostate and lung cancer, keeps skin and tissues healthy, plays a significant role in immune system and bone growth
eggs, shrimps, fish, beef liver, butter, cheese, carrots, pumpkins, mangoes, potatoes

Vitamin B1 (Thiamine)

converts food into energy, keeps skin and hair healthy, protects muscles and brain, very important for nerves functioningpork, ham, brown rice, soymilk, acorn squash, watermelons

Vitamin B2 (Riboflavin)

converts food into energy, responsible for skin and hair condition, protects brain, important for blood circulationeggs, milk, cheese, yogurt, green leafy vegetables, grains and cereals, meat

Vitamin B3 (Niacin)

converts food into energy, enables the functioning of nervous system, important for skin, hair and blood cells conditionfish, meat, poultry, mushrooms, whole grains, peanut butter, potatoes

Vitamin B5 (Pantothenic Acid)

converts food into energy, responsible for making fats, steroid hormones, hemoglobin and neurotransmitterschicken, yolk, eggs, broccoli, whole grains, avocados, tomatoes, mushrooms

Vitamin B6 (Pyridoxine)

lowers homocysteine level, reduces the risk of heart diseases, converts tryptophan to serotonin and niacin, responsible for a good sleep, mood, cognitive abilities and appetite, plays a significant role in immune systemfish, meat, poultry, tofu, soy products, legumes, bananas, potatoes

Vitamin B12 (Cobalamin)

lowers homocysteine level, lowers the risk of heart diseases, take part in making new cells, breaks down fatty acids and amino acids, enables the growth of nerve cells, take part in producing DNA and red blood cellspresent in animal products


converts food into energy, synthetizes glucose, makes and breaks down some fatty acids, responsible for skin, hair, bones and nails conditionorgan meats, fish, nuts, seeds

Vitamin C (Ascorbic Acid)

lowers the risk of stomach, breasts, esophagus and mouth cancers, prevents vision problems, e.g. cataracts, takes part in collagen production, is an antioxidant, protects immune systemcitrus fruits, fresh juices, potatoes, red pepper, broccoli, spinach, tomatoes, Brussels sprouts


important for nerve system - enables nerves and brain activity, takes part in transporting and metabolizing fatseggs, milk, salmon, peanuts

Vitamin D

forms healthy bones and teeth, maintains the level of calcium and phosphorus in blood, reduces non-spinal fractures, beneficial for immune systemfortified margarine or milk, fatty fish, but generally produced from sun exposure

Vitamin E

antioxidant, prevents Vitamin A and some lipids from damaging, prevents Alzheimer’s diseaseoils, margarines, wheat germ, whole grains, nuts, leafy green vegetables

Vitamin B9 (Folic Acid)

enables new cells creation, prevents such birth defects as spine and brain defects - thus recommended for pregnant women, regulates the homocysteine level, reduces the risk of heart diseases and colon cancerasparagus, spinach, broccoli, legumes, orange or tomato juices, okra

Vitamin K

prevents hip fractures, activates calcium and proteinseggs, milk, cabbage, liver, spinach, prouts, kale, collards



FOOD SOURCES (examples)


builds and protects teeth and bones, responsible for muscles relaxation and contraction, supports the transmission of nerve impulses, activates some enzymes, regulates blood pressurecheese, milk, tofu, yogurt, salmon, leafy green vegetables


responsible for balancing body fluids, an element of stomach acid - enables digestionsalt, soy sauce


regulates the level of blood glucose, enhances the insulin activity, enables releasing energy from glucosepoultry, meat, fish, eggs, nuts, cheese, potatoes


makes red blood cells, takes part in iron metabolism process, important for immune systemshellfish, liver, seeds, whole grains, cocoa, pepper, beans


prevents dental cavities, makes bones strongtoothpaste with fluoride, marine fish, tea


element of thyroid hormone, enables reproduction, functioning and growth of muscles and nervesiodized salt, seafood


helps in oxygen transportation, important for body chemical reactions, enables collagen and hormones productionred meat, grain products, poultry, eggs, green vegetables


important for body chemical reactions, regulates blood pressure, works with calcium in blood clotting and muscle contraction, responsible for strong bones and teethgreen vegetables, legumes, sunflower seeds, halibut, milk, whole-wheat bread


important for bones forming, metabolizes amino acids, carbohydrates and cholesterolnuts, fish, tea, whole grains


element of some enzymes, prevents neurological damages in infantsLegumes, milk, nuts


builds and protects bones and teeth, it is a part of RNA and DNA, converts food into energydairy products, fish, poultry, eggs, green peas, potatoes, broccoli, almonds


responsible for fluid balance, regulates heartbeat, enables sending nerve impulses, lowers blood pressure, enables muscle contractionmilk, meat, fruits and vegetables


antioxidant, regulates the activity of thyroid hormoneseafood, organ meats, grains, walnuts


responsible for fluid balance, enables sending nerve impulses, regulates blood pressuresalt, soy sauce


important for shaping protein structure, responsible for hair, nails and skin conditionfish, meat, poultry, legumes


enables forming some enzymes and proteins, responsible for cell creation, prevents storage of Vitamin A in the liver, responsible for immune system, wound healing, smell and tastered meat, poultry, seafood, nuts, beans


As we can see, vitamins and minerals are responsible for the most important body functions. But are there any extra vitamins needed after bariatric surgery or are vitamins required immediately after bariatric surgery? We will explain it in the following paragraphs.

Hands vitamins and flowers

After the surgery, a dietician with the help of the surgeon prepares an individual plan of supplementation for the patient that will meet nutritional needs. The plan depends on many factors and it is different for different patients

Vitamins to prevent hair loss after weight loss surgery

Hair loss after bariatric surgery is a very common side effect. It is usually temporary – appears about 2-3 months after the surgery and after a few months, it is resolved. However, patients are usually advised to take vitamins to prevent hair loss after weight loss surgery – these are usually: Biotin, Iron, Vitamin C, Vitamin D, and zinc. 

When can you start taking vitamins after bariatric surgery?

If you wonder when can you start taking vitamins after bariatric surgery, you should know that your bariatric surgeon together with a dietician should prepare an individual plan of supplementation that will meet your nutritional needs. Such a plan depends on the surgery that you had, your age, health condition, sex, and will be modified once you will be entering new diet steps – so you should not buy anything in advance without consulting the doctor. If you are taking supplements on a daily basis before the surgery, you should also ask the surgeon if you can take them (some substances may disturb the surgery). The role of your individual supplementation would be preventing nutritional deficiencies, so you would start it just after the surgery. There are some norms and generalized Vitamin and mineral supplementation for bariatric patients, the thing is that you do not know which of them your organism will need and what dosages you will have

What vitamins to take after weight loss surgery

What are the best vitamins to take after bariatric surgery? Well, it depends on some factors, so we cannot say what are the best vitamins after bariatric surgery, but we can say what are the most popular vitamins and minerals needed after bariatric surgery among bariatric surgery patients.

These are multivitamins, Vitamin B12, Iron, and calcium.

  • Multivitamin – regardless of the surgery type, bariatric patients end up eating much less than average people, so they tend to lack numerous vitamins. Multivitamin allows for supplementing the most important Vitamins in one dose. It is important that it contains Vitamin A, a group of Vitamins B, Vitamin C, calcium, biotin, iron, and folate. Individual patients may be recommended a specific brand of such multivitamin or specific composition of Vitamins. 
  • Vitamin B12 – the problem here is that Vitamin B12 is released from food and absorbed thanks to stomach acids. Some bariatric surgeries, e.g. gastric sleeve or bypass, disturb the food and vitamin absorption, so this vitamin must be supplied with an intranasal spray, injection, or tablets.
  • Calcium – there have been studies which prove that bariatric patients tend to have problems with hands, feet, hip, or spine fractures caused by calcium deficiency within 7 years after the surgery. Hence, calcium supplementation is extremely important. The dosages depend on the surgery type, but this mineral should never be omitted in post-op supplementation. 
  • Iron – iron deficiency causes anemia, gastric bypass patients are at the highest risk of iron deficiency. The reason for it is that duodenum – an area where iron absorption takes place – is bypassed. Iron is recommended to most bariatric patients, but after gastric bypass, patients need to be extremely careful about its supplementation. 

Of course, these are not the only recommended supplements, they are just the ones that all bariatric patients must take. Again, it is a surgeon or dietician that confirms which supplements to choose. Also, if you take any other tablets – for hair loss, skin, nails, allergies, any multivitamin, mention about them – the surgeon will surely take it into consideration and will choose such supplements that would cover all your needs

Vitamins after gastric sleeve

All patients need to take vitamins after gastric sleeve surgery. If you want to get the best vitamins after gastric sleeve, just ask your surgeon or dietician for recommendations. 

Clinic Hunter- Gastric Sleeve


What vitamins should I take after gastric sleeve surgery? Usually, they include:

  • complete multivitamin
  • iron
  • Vitamin C
  • Vitamin B12
  • Vitamin D
  • Calcium (about 1500mg).

Vitamins after gastric bypass

Vitamins after gastric bypass are poorly absorbed, so definitely you need to supplement them. Not taking vitamins after gastric bypass would deteriorate your health very fast. Thus patients must be particularly careful about taking vitamins needed after gastric bypass. The surgeon should recommend the best vitamins after gastric bypass that would prevent any deficiencies. What vitamins and minerals do I need after gastric bypass?

Clinic Hunter gastric bypass

Usually, they are:

  • Calcium (about 1800mg)
  • complete multivitamin
  • Vitamin C
  • Vitamin D
  • iron supplements
  • complex of Vitamins B.

Vitamins after gastric band

The gastric band does not affect food and Vitamin absorption, so it is easier for patients to get micronutrients from food. Yet, the supplementation might be needed when medical tests show some deficiencies.

Gastric Band ilustration

The usual gastric band vitamins include:

  • calcium (up to 1500mg)
  • Vitamin D
  • complete multivitamin.

Vitamins after duodenal switch

Duodenal switch is a combination of gastric sleeve and bypass, so naturally, it is a very complex surgery that affects nutrients absorption. The surgeon will tell you what vitamins to take after the duodenal switch, and you must follow this advice to avoid health problems. What vitamins do you take after the duodenal switch?

They are:

  • calcium (up to 2500mg)
  • good quality multivitamin with iron, selenium, and zinc
  • Vitamin A
  • Vitamin C
  • Vitamin D
  • Vitamin K
  • Vitamin B group.

Possible side effects from not taking vitamins after weight loss surgery

Woman in Gray Tank Top Lying on Bed

Not taking the vitamins after weight loss surgery may have a huge influence on the general health condition of the patient

Taking vitamins after weight loss surgery is something that patients commit to before having the operation. It is an indispensable part of post-op life. The possible side effects from not taking vitamins after weight loss surgery may be very dangerous – both for physical and mental health.

See what happens when you don’t take vitamins after weight loss surgery:

  • Calcium deficiency: memory loss, tingling, and numbness in hands, feet, and face, muscle cramps or spasms, depression, nails problems, increased risk of bones fracturing, hallucinations
  • Vitamin C deficiency: fever, nausea, vomiting, bleeding gums, poor wound healing, malaise
  • Vitamin D deficiency: pain in muscles, bones, overall weakness and fatigue, high blood pressure
  • Vitamin B12: tingling and numbness in fingers, hands and face, anemia
  • Vitamin B9 (folic acid): weakness and fatigue, diarrhea, headache, palpitations
  • Thiamin: chronic vomiting, neuropathy, burning feet, nausea, breath shortness, constipation.

If you experience any sign of malnutrition, you should visit a doctor and adjust supplementation because apart from the symptoms that you are experiencing, the vitamin and mineral deficiency affects the organs, functioning, and processes inside your body that you do not feel at the beginning. 


Bariatric surgery patients are particularly exposed to nutrition complications, but the individual plan, effort, motivation, and commitment may successfully prevent it. A weight loss surgery is a dramatic experience and considerable change for your body and mind, so you should remember not to burden yourself with vitamin and mineral deficiencies. What we suggest is that you make the supplementation a part of your daily routine and focus on living your new life to the full!


size plus lady on the colorfull background


“Post-Bariatric Surgery Vitamins and Supplements.” UPMC,

Publishing, Harvard Health. “Listing of Vitamins.” Harvard Health,

Staff, written by OC. “Vitamin Guidelines After Bariatric Surgery.” Obesity Coverage,

“Vitamins & Minerals After Bariatric Surgery.” The Dietologist,

“Vitamins and Minerals.”,

WeightWise, and Name *. “Your Guide to Bariatric Vitamins After Weight Loss Surgery: WeightWise.” WeightWise Bariatric Program, 21 Jan. 2020,

“Which Vitamins Do I Really Need?” Obesity Action Coalition,

Klaudia Grabowska

Klaudia started to work for Clinic Hunter many years ago, just after graduating from the John Paul II Catholic University of Lublin in Poland and since that time, this job has become her biggest passion and inspiration.

She has gained necessary expertise and experience by serving patients from all over the world (mainly the UK, Scandinavian countries, and the USA), taking an active part in numerous live and video trainings with clinics in Poland, Hungary and Turkey, participating in international medical tourism conferences and events, and completing internal Clinic Hunter courses. Now, Klaudia is an accomplished patient advisor specialising in such fields as dentistry, plastic and bariatric surgery and hair loss treatment. Her main idea is helping people nad making their lives better, that is why this job brings her so much satisfaction and joy.

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