What happens in the body?

Weight loss surgery means changes inside-out. The external changes are often easier to notice than what happens on the inside. For example, the body’s capacity to absorb vitamins and minerals decreases after the operation. This is important to know so that you can help give the body what it needs!

Why do you vitamin and mineral needs change after WLS?

  • You are eating less than before.
  • The food is passing through the gastrointestinal tract faster.
  • Limited amount of hydrochloric acid, which is needed to absorb certain nutrients
  • The pH-level in the stomach increases creating a less acidic environment. An acidic environment is needed for absorption.
  • If parts of the intestine are bypassed, there is less area for absorption.

Baricol Complete sample pack

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In our sample package, you get a daily dose of all varieties powder, chewable, effervescent, and tablet as well as informational material. 

How is vitamin and mineral absorption affected after WLS?

Gastric Sleeve

When undergoing a VSG, the outer curve of the stomach is removed (approximately 85%), making the space for food much smaller. The feelings of hunger then sharply decrease because the hunger hormone (ghrelin) is largely housed in the part of the stomach that is removed.  The main reason why you need to take supplements of vitamins and minerals after your operation is that in addition to eating less, you now have a very limited amount of hydrochloric acid in your stomach which is needed for the activation and absorption of various vitamins and minerals.

Gastric Bypass

During a gastric bypass, the majority of your stomach is disconnected from the part of your stomach near the oesophagus, leaving you with a new pouch of about 15-20ml. The intestine is then connected to this pouch – bypassing the stomach.  Due to less space and changes to hunger and satiety hormones within the gastrointestinal tract, feelings of hunger are reduced.  After a gastric bypass, there is also very little hydrochloric acid produced in the stomach which is needed to activate and absorb certain nutrients. In addition, absorption is reduced due to bypassing the first part of the intestine.

Important Vitamins after Your Weight Loss Surgery

Vitamin B12

VITAMIN B12 needs two things from the stomach to be absorbed: hydrochloric acid (HC) and a protein known as Intrinsic Factor (IF). After bariatric surgery, you have less HCl and IF and, therefore, reduced B12 absorption. By taking large amounts of B12 from supplements, you can absorb it in a typical way with the help of stomach acid and IF as well as through passive diffusion in the intestines.

Vitamin D

VITAMIN D is absorbed in the part of the intestine that is bypassed during a gastric bypass, plus it needs hydrochloric acid to be absorbed best.  It also gets harder to get enough vitamin D from the sun the further you live from the equator. Foods that contain vitamin D are fatty fish and enriched products like certain dairy foods. Vitamin D plays an important role in bone health and in the ability to absorb calcium and phosphate from food.  This vitamin is not just an important resource for bone-building but also prevents your body from using the minerals in your bones to maintain normal calcium and phosphate levels in the blood.


THIAMINE, or vitamin B1, is used in carbohydrate metabolism and is also involved in nerve and muscle function. You can find it in a variety of foods including beef, pork, legumes and peas, nuts and seeds, citrus fruit, and whole and enriched grains. Thiamine deficiency is one of the more common concerns related to vitamins in the first few weeks to 3 months after bariatric surgery. Risk factors include rapid weight loss, prolonged nausea and vomiting, and not taking vitamins after surgery

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Folic Acid

FOLIC ACID from supplements and folate from foods are different forms of the same B vitamin (B9). It is needed for the production of proteins, cell reproduction, and red blood cell formation.  You will find folate in leafy greens, citrus fruits, legumes, eggs, and whole and enriched grains. Deficiency of folic acid can result in anaemia with characteristics of lethargy, weakness, irritability, dizziness, and headache.  With a severe deficiency, shortness of breath and even chest pain (angina) can occur.

Important Minerals after Weight Loss Surgery


Zinc is a vital mineral that is important for the immune system and metabolism.  Zinc is also good for the growth of healthy hair, skin, and nails. It is absorbed in the upper part of the intestine which is bypassed during a gastric bypass. In addition, hydrochloric acid, which is decreased after both the sleeve and bypass, is needed to release zinc from food and to help with absorption. 


CALCIUM is required to keep a constant level of calcium in the blood. If there is too little calcium coming from outside sources (foods and supplements), then the body will acquire it from your bones. Calcium is mainly absorbed in the part of the intestine that is bypassed by the gastric bypass. After surgery, you need to supplement both calcium and vitamin D to maintain good levels of calcium so that your body doesn’t need to go to your skeleton to get it.


IRON deficiency is very common after WLS. Absorption is decreased with both the bypass and sleeve due to decreased levels of hydrochloric acid in the new stomach, and it’s also absorbed in the part of the intestine that is bypassed during the gastric bypass. Food also empties from your stomach faster after WLS which gives the body less time to change the iron into a form that your body can use (Fe3+ -> Fe2+). Absorption is better from supplements that contain a citrate form of iron since this helps get around the reduced levels of stomach acid. 

Everything your Body Needs – Every Day

Compare the Nordic Guidlines to Baricol Complete

Nordic Guidelines

  • Iron 45-60 mg
  • Vitamin B12 >350 µg
  • Vitamin D 800 IU
  • Folic acid 400 µg
  • Thiamine 1,1-1,4 mg
  • Zinc 9 mg
  • Calcium >500 mg

Baricol® Complete

  • Iron 50 mg
  • Vitamin B12 700 µg
  • Vitamin D 1800 IU
  • Folic acid 400 µg
  • Thiamine 2,0 mg
  • Zinc 21 mg
  • Calcium Citrate 1000 mg

All Ingredients