Which vitamin should be supplemented after bariatric surgery: a. Vitamin B12, b. Vitamin B9, or c. Folic acid?

From the Guidelines

Vitamin B12 (option a) is the correct vitamin to supplement after bariatric surgery, as it is essential for preventing megaloblastic anemia, peripheral neuropathy, and other neurological complications that can arise from impaired absorption due to reduced production of intrinsic factor and decreased exposure to gastric acid. After bariatric procedures, particularly those involving the stomach such as gastric bypass or sleeve gastrectomy, patients develop impaired absorption of vitamin B12, which can lead to severe and irreversible neurological damage if left untreated 1. Patients typically require lifelong supplementation with vitamin B12, usually administered as oral crystalline vitamin B12 at doses of 1000 mcg daily or as monthly intramuscular injections of 1000 mcg if absorption is severely compromised 1. While folic acid (vitamin B9, options b and c are actually the same vitamin) supplementation is also recommended after bariatric surgery, vitamin B12 deficiency is more common and clinically significant, making it the priority supplement for these patients.

Key Considerations

• Vitamin B12 deficiency can lead to megaloblastic anemia, peripheral neuropathy, and other neurological complications if left untreated 1
• Impaired absorption of vitamin B12 is common after bariatric surgery, particularly after gastric bypass or sleeve gastrectomy 1
• Lifelong supplementation with vitamin B12 is typically required, with doses of 1000 mcg daily or monthly intramuscular injections of 1000 mcg if absorption is severely compromised 1
• Folic acid supplementation is also recommended, but vitamin B12 deficiency is more common and clinically significant, making it the priority supplement for these patients 1

Recommended Supplementation

• Vitamin B12: 1000 mcg daily or monthly intramuscular injections of 1000 mcg if absorption is severely compromised 1
• Folic acid: 400 μg/d should be included in the routine multivitamin; pregnant women or those planning to conceive should take 800–1000 μg folic acid/d included in a multivitamin supplement or separately 1

From the FDA Drug Label

Patients with pernicious anemia should be informed that they will require monthly injections of vitamin B12 for the remainder of their lives. A vegetarian diet which contains no animal products (including milk products or eggs) does not supply any vitamin B12. The need for vitamin B12 is increased by pregnancy and lactation.

The vitamin that should be supplemented after bariatric surgery is: a. Vitamin B12.

• Vitamin B12 supplementation is necessary due to the potential for malabsorption after bariatric surgery.
• Vitamin B9 and Folic acid are related, as folic acid is another term for vitamin B9, but the primary concern after bariatric surgery is Vitamin B12 deficiency. 2 2

From the Research

Vitamin Supplementation after Bariatric Surgery

The question of which vitamin should be supplemented after bariatric surgery can be addressed by examining the provided evidence.

• Vitamin B12 deficiency is a common issue after bariatric surgery, as noted in studies 3, 4, 5, 6, 7.
• The evidence suggests that vitamin B12 supplementation is necessary to prevent deficiency and related complications, such as hematologic and neurologic complications 3, 5, 6.
• Oral vitamin B12 supplementation has been shown to be as effective as intramuscular supplementation in maintaining serum vitamin B12 levels within reference values 4.
• The optimal dose of vitamin B12 supplementation is still a topic of debate, but 350 μg oral vitamin B12 is suggested as an appropriate dose to correct low vitamin B12 levels in many patients 7.
• Vitamin B9, also known as folic acid, is not specifically mentioned as a necessary supplementation after bariatric surgery in the provided evidence.
• Folic acid is equivalent to Vitamin B9, and there is no evidence to suggest that folic acid or Vitamin B9 supplementation is necessary after bariatric surgery based on the provided studies.

Comparison of Options

• Option a: Vitamin B12 is supported by the evidence as a necessary supplementation after bariatric surgery 3, 4, 5, 6, 7.
• Option b: Vitamin B9 is not supported by the evidence as a necessary supplementation after bariatric surgery.
• Option c: Folic acid is equivalent to Vitamin B9 and is not supported by the evidence as a necessary supplementation after bariatric surgery.