Why do many bariatric patients need to watch for vitamin B12 deficiency before or after bariatric surgery? You probably already know that bariatric patients need higher doses of certain vitamins after surgery: the changes to the digestive system that limit calories also limit how much vitamins and minerals are absorbed. What are these changes, and how common is this issue? For vitamin B12 specifically, a couple of factors make it important to get enough from your post-op vitamin regimen.
Key takeaways
- Bariatric surgery reduces stomach acid and intrinsic factor, both needed to absorb vitamin B12.
- The body can store vitamin B12 for years, so normal lab results soon after surgery do not mean you can stop your vitamins.
- The ASMBS recommends 350–1,000 mcg of vitamin B12 orally, daily.
What is vitamin B12 and its role?
Vitamin B12 is a water-soluble vitamin naturally found in most animal products, such as meat, dairy and eggs. It is also found in fortified foods such as bread and cereal. Vitamin B12 is required for forming red blood cells, neurological health and DNA synthesis. Deficiency can cause:
- Megaloblastic anaemia
- Fatigue
- Neurological issues
- Numbness
- Tingling of the hands and feet
- Impaired balance
- Memory loss
Although most adults get plenty of vitamin B12 from their diet, deficiencies affect about 1.5–15% of the general population, in particular older adults and people with gastrointestinal disease. People who have had bariatric surgery are also at risk, for two main reasons.1
Vitamin B12 absorption
First, vitamin B12 is released from food by stomach acid. After this initial breakdown, intrinsic factor is secreted into the stomach to bind with vitamin B12 and help it be absorbed later in the intestines. Bariatric surgery either bypasses (as in the Roux-en-Y gastric bypass) or restricts (as in the sleeve gastrectomy) the stomach, resulting in less acid and less intrinsic factor. This creates a need for increased vitamin B12 intake from supplements after surgery.2
According to Liz Goldenberg, MPH, RDN, CDN, programme coordinator of gastrointestinal, metabolic and bariatric surgery at New York-Presbyterian Hospital, "…the body has the ability to store vitamin B-12 for a long period of time, perhaps years; thus, vitamin B-12 status immediately following sleeve surgery may be normal."3 This means good initial lab results do not let you off the hook for taking vitamins long term.
Deficiency rates
Vitamin B12 deficiency is one of the most common deficiencies bariatric patients experience after surgery.3 Two to five years after surgery, deficiency rates are below 20% for Roux-en-Y gastric bypass patients and 4–20% for sleeve gastrectomy patients.4 The ASMBS recommends 350–1,000 micrograms (mcg) taken orally, daily, to maintain good vitamin B12 status.4 Fortunately, high-quality bariatric vitamins make it easy to meet all your vitamin needs after surgery. As with any aspect of health, prevention is key.
Sources
- Office of Dietary Supplements – Vitamin B12. Retrieved 31 August 2020, from https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
- Seeniann J, Hoegerl C. (2009). Nutritional deficiencies after gastric bypass surgery. J Am Osteopath Assoc, 109(11), 601-604.
- Alexander A. (28 January 2019). Nutritional deficiencies common before and after bariatric surgery. Retrieved 31 August 2020, from https://www.healio.com/news/endocrinology/20190128/nutritional-deficiencies-common-before-and-after-bariatric-surgery
- Mechanick JI, Apovian C, Brethauer S, et al. (2020). Clinical Practice Guidelines for the Perioperative Nutrition, Metabolic, and Nonsurgical Support of Patients Undergoing Bariatric Procedures – 2019 Update. Obesity, 28(4). doi:10.1002/oby.22719
This article is for general information only and does not replace personal medical advice. Always discuss your situation, blood test results and supplementation with your bariatric team or healthcare provider.