Nutritional Deficiencies
Bariatric Surgery: Nutritional Deficiencies and Vitamin Supplements
There are several types of common bariatric surgical procedures, but they all have one thing in common: they change the way your body deals with food. Nutritional deficiencies following bariatric surgery are commonly reported in scientific literature on surgery and nutrition, but these deficiencies and their related health complications can be prevented with the appropriate use of vitamin supplements.
The frequency, severity, and type of nutritional deficiencies experienced vary depending on the type of bariatric surgical procedure that was performed. Bariatric surgeries are classified based on how they work: restrictive procedures limit food intake, while malabsorptive procedures affect nutrient absorption by bypassing a portion of the intestine. As might be expected, malabsorptive procedures are the most likely to impact vitamin and mineral absorption and result in nutritional deficiencies.
Biliopancreatic diversion (BPD), a malabsorptive procedure that works by using a short portion of distal small intestine, appears to have the greatest impact on nutrient absorption. Purely restrictive surgeries such as gastric adjustable banding and gastroplasty, which do not bypass any of the part of the intestine, have the least nutritional impact. The most commonly performed procedure in the United States is Roux-en-Y gastric bypass, a malabsorptive procedure. The following are the most commonly recommended nutritional supplements after bariatric surgery according to a recent research study by Malone and colleagues.
Vitamin B12 and Folate
Roux-en-Y gastric bypass is known to have a significant effect on B12 absorption, with about one-third of gastric bypass patients experiencing a B12 deficiency one year after the procedure. There are several reasons for this common nutritional complication of gastric bypass surgery:
- The source of vitamin B12 is usually red meat. Vitamin B12 must be separated from meat protein in order to be absorbed, but the amount of gastric acid produced by the new stomach pouch is inadequate to do this.
- Meat is poorly tolerated after surgery, often leading patients to limit their intake.
- Intrinsic Factor, a protein needed for the absorption of B12, may be less available in patients after surgery.
Since gastric banding and BPD do not affect the stomach’s production of gastric acid or intrinsic factor, they are less likely to lead to a Vitamin B12 deficiency.
Folate is a water-soluble vitamin, and therefore it is not stored in the body in significant quantities. Many patients experience a decrease in folate levels following bariatric surgery, as their newly limited food intake fails to provide adequate folate. Unlike vitamin B12, folate is absorbed throughout the small intestine. Therefore, malabsorptive procedures are not necessarily more likely to result in a folate deficiency than restrictive procedures. However, vitamin B12 is needed to convert folate to its active form, so a B12 deficiency can lead indirectly to a folate deficiency.
Thiamine
A multivitamin supplement will provide adequate amounts of thiamine for most people, but patients who experience persistent vomiting or extremely rapid weight loss after surgery are at risk for developing a thiamine deficiency. Without an adequate intake of thiamine, a water-soluble vitamin like folate, the body’s small stores will become depleted in under three weeks. Thiamine deficiency is a very serious condition, but unusual in patients who take a multivitamin and do not experience excessive vomiting.
Calcium and Vitamin D
Reports indicate that up to half of obese bariatric surgery patients have a preexisting vitamin D deficiency. As the surgical procedure then results in reduced intake and compromised absorption, supplements are usually needed to maintain appropriate levels of calcium and vitamin D. Of the various types of bariatric surgeries, BPD is associated with the greatest risk for multiple nutritional deficiencies. However, even restrictive procedures limit nutritional intake, and supplements are recommended for all patients. Bariatric surgery patients—especially recipients of malabsorbtive procedures—are likely to have problems with bone mineral density and metabolism, with those most at risk being the extremely obese, postmenopausal women, and patients with the largest weight loss after surgery.
Iron
Iron deficiency is common among bariatric surgery patients, particularly those who have undergone procedures with a malabsorptive component. As with Vitamin B12 deficiency, the reasons for inadequate iron are several:
- The reduced ability of the stomach to produce gastric acid limits the conversion of dietary ferric iron to ferrous iron, which is more easily absorbed.
- Patients often have an inadequate consumption of iron, which can be a result of a limited intake of meat post-surgery.
- Some surgical procedures bypass the nearest site for absorption of iron, in the duodenum and jejunum.
To compensate for a potential iron deficiency, a multivitamin with iron and vitamin C (which may enhance iron absorption) is recommended.
Zinc and Magnesium
There have been reports of both zinc and magnesium deficiencies in bariatric surgery patients, particularly among those who underwent BPD. Some believe that hair loss, a common occurrence after bariatric surgery, may be related to a zinc deficiency. The available literature does not reflect any significant complications resulting from magnesium deficiency.
In Conclusion
Nutritional supplements are required after bariatric surgery, which is why gastric bypass tools that help you track your nutrient intake can offer some help. In general, restrictive procedures present the lowest risk for postoperative nutritional deficiencies among patients. Bariatric surgical procedures that are malabsorptive in nature are much more likely to result in nutritional deficiencies, and patients who undergo these procedures must compensate with supplements. This is particularly true for BPD, which is associated with a number of deficiencies.
