FitForMe is trusted by 200,000+ customers and 8000+ healthcare professionals
FitForMe is trusted by 200,000+ customers and 8000+ healthcare professionals
Trustpilot score: 4.4 out of 5
If you compare the composition of a WLS multivitamin with a regular multivitamin, one thing stands out immediately. There is a big difference in the amount of vitamin B12. The dose of B12 in the WLS multivitamin is significantly higher.
So what exactly is vitamin B12, and why do you need so much of it after weight loss surgery? Read all about it in this blog.
What does vitamin B12 do?
Vitamin B12 plays an important role in the production of red blood cells. These blood cells transport oxygen in your blood. The oxygen you breathe in through your lungs reaches every part of your body this way.
Your body needs oxygen to produce energy - for example, by burning food. The carbon dioxide your body produces through this process is transported back to your lungs so you can breathe it out.
B12 is therefore extremely important for your energy metabolism, so your body can function properly. Too little B12 can be related to symptoms such as tiredness and fatigue.
Which foods contain vitamin B12?
Vitamin B12 is found only in animal products, such as meat, milk, eggs, yoghurt, and cheese. This is because B12 is produced by certain bacteria that live in the stomachs and intestines of animals.
Vitamin B12 is also often added to plant-based products, such as a vegetarian burger or oat milk. It will be listed separately on the product's packaging.
Why do you need so much B12 after weight loss surgery?
To explain that, it's important to understand how vitamin B12 is absorbed in your body. Weight loss surgery has a significant impact on this process, meaning much less vitamin B12 can be absorbed from food.
How vitamin B12 is absorbed by the body:
The absorption of vitamin B12 is a complex process with many steps.
Step 1: The stomach extracts B12 from food
In food, vitamin B12 is bound to a protein. Your body needs to extract the B12 from that food and separate it from the protein. This requires stomach acid and the enzyme pepsin. The B12 is then separated from the protein and temporarily bound to another protein. After that, the B12 moves on to your small intestine.
Step 2: The first part of the small intestine couples B12
In the first part of your small intestine, the B12 is recognised. The protein is then replaced by an Intrinsic Factor. This was already produced by your stomach lining, but can only be coupled in the small intestine. The B12 then travels with the Intrinsic Factor to another part of your small intestine.
Step 3: The last part of the small intestine absorbs B12
In the last part of your small intestine, vitamin B12 is actually absorbed into the blood. But really only when it is coupled to the Intrinsic Factor. Only about 1% of the vitamin B12 in your small intestine can be absorbed without the Intrinsic Factor.
So your stomach plays an important role in the absorption of vitamin B12 in your small intestine, through the production of that Intrinsic Factor.
The absorption of vitamin B12 after weight loss surgery
After weight loss surgery, you produce far less stomach acid. This makes it difficult for your stomach to extract vitamin B12 from food. You therefore need extra vitamin B12 from a supplement.
But weight loss surgery also means your stomach no longer produces the Intrinsic Factor. As a result, the vitamin B12 that reaches your small intestine is barely absorbed. Around 1% still enters your bloodstream - but this is much less than before surgery.
Because you only absorb around 1%, FitForMe WLS multivitamins contain far more vitamin B12 than regular multivitamins. This means you take in so much B12 that the amount absorbed into your blood is sufficient.
And the excess? Your body simply passes it out.
