Bariatric Surgery FAQ

Vitamin B12 After Gastric Bypass

Vitamin B12 After Gastric Bypass - Bariatric Fusion

Gastric bypass surgery can work wonders to suppress your appetite for weight loss when traditional methods have failed. But there’s a major point that people often overlook: nutritional deficiency.

The mechanism of gastric bypass surgery is to cause restriction by creating a smaller stomach pouch and then causing nutrient malabsorption by bypassing a portion of the stomach and small intestine. You're eating much less than before and experiencing malabsorption of nutrients coming from food sources. This increases the risk of nutritional deficiencies.

This may sound scary, but nutrient deficiencies can be easily prevented with proper supplementation after surgery. In this article, we’ll go over the risk of vitamin B12 deficiency and the need for supplementation after gastric bypass surgery.

What This Article Covers:

Gastric Bypass Overview

Before we go over vitamin B12 supplementation, it’s essential to understand the mechanism of gastric bypass surgery that results in the higher risk of vitamin B12 deficiency.

How the Body is Alteredgastric bypass

Gastric Bypass surgery is considered the gold standard of bariatric surgeries. First, the surgeon will divide the stomach to create a small stomach pouch. A large portion of the stomach will no longer be used, but instead bypassed. This decreases the stomach’s capacity to only be able to hold 1 oz.

The second step of the surgery is where the surgeon will connect the new stomach pouch to a specific part of the small intestine, making food travel quickly from your stomach to the small intestine.

How It Affects Digestion Digestion

When you are consuming a smaller amount of food every day, you are reducing the amount of nutrients you are taking in. This may be forgotten in the chaos of surgery.

Remember, not only is the body being restricted from the amount of calories and nutrients you are consuming, but you will also be experiencing malabsorption. Bypassing a large portion of the stomach and small intestine will cause absorption of fewer calories and nutrients. There is decreased gastric acid that some nutrients require to be absorbed. Also, a number of vitamins and minerals are absorbed in the first portion of the small intestine that is bypassed, requiring supplements for life.

How It Can Cause a Vitamin B12 Deficiency

Vitamin B12 Deficiency

In the stomach, there's a paper-thin layer called the gastric mucosa. This layer releases intrinsic factor that helps the stomach to absorb vitamin B12 from food. The new stomach pouch is so small that there is a decrease in gastric acid. When food is traveling through this small section of the stomach, the gastric mucosa is unable to provide enough intrinsic factor to allow vitamin B12 to be adequately absorbed.

Effects of Vitamin B12 Deficiency

Vitamin B12 is essential for proper maintenance of the nervous system, red blood cell formation, and production of DNA. Vitamin B12 deficiency can result in a form of nutritional anemia that can make you feel tired and weak.

The problem is that you might not notice a difference at first. There's around a 20% chance of Vitamin B12 deficiency 2-5 years out from bariatric surgery.

That being said, we will discuss how to proactively prevent this deficiency.

Vitamin B12 Supplementation

If you searched for supplementation before, you probably noticed different methods on the market: chewables, tablets, nasal sprays and more.

A daily dose of 350-1000mcg is recommended for most bariatric patients. This amount can usually be found in most bariatric specific multivitamin supplements. However, some individuals may require additional supplementation based on blood work and other medical conditions.

Only take a dietary supplement if it is specifically recommended by a qualified healthcare professional.

Sublingual B12 Tablets

One of the easiest and most effective ways to supplement vitamin B12 is sublingually, or tablets that dissolve under the tongue.

The absorption process starts in the mouth. So, Bariatric Fusion’s sublingual B12 tablets are convenient, well absorbed and affordable.


Each tablet contains 1,000 micrograms of vitamin B12 and an additional 200 micrograms of folic acid. These 2 vitamins work hand in hand in red blood cell production and assist in proper Iron function.

Do I Purchase a Vitamin B12 Supplement

Most bariatric specific multivitamin supplements contain vitamin B12 in the recommended amounts. A supplement that only contains vitamin B12 or a mixture of B-vitamins is generally recommended for those with higher needs to be taken in addition to a bariatric multivitamin.

Fun Fact for Vitamin B12 Absorption

Did you know that probiotics may increase the absorption of vitamin B12 in the gut?

The gut is filled with different strains of good and bad bacteria. After a dose of antibiotics, dealing with chronic GI conditions, or GI surgery, the good bacteria in your gut can be diminished or even relocated. This can lead to a number of issues from decreased immune response, inflammation, and decreased nutrient absorption.

Balancing out the GI tract with food sources containing probiotics or probiotic supplements can offer better digestion, support immune response, enhance vitamin B12 absorption, and even promote regular bowel movements.

Probiotics are by no means a replacement for vitamin B12 supplements, however, they may help increase absorption and even address some further GI issues you may be dealing with.

Final Thoughts

Supplements are essential for life after bariatric surgery. You should be getting regular blood work done at the request of your healthcare provider after weight loss surgery to monitor vitamin and mineral levels.

Deficiencies can be easily prevented with proper supplementation. If you find yourself experiencing a deficiency, consult with your healthcare provider for corrective intervention. Fortunately, there are a wide variety of bariatric specific preventative and corrective supplements available.

Gastric bypass is an excellent weight loss tool when traditional weight loss methods have failed. However, this lifelong change is anything but easy. Supplementation, balanced diet, and exercise should be implemented for life to experience the most benefit out of your weight loss journey.

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**This blog is for information and education purposes only. This information is not intended to substitute professional medical advice, diagnosis, or treatment. Please consult with your physician or another qualified health provider with any questions in regards to a medical condition. A qualified healthcare professional can best assist you in deciding whether a dietary supplement is suitable based on your individual needs.

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