Gastric bypass surgeries or gastric bypass procedures divide the stomach into two compartments or pouches: a small upper portion and a much larger lower portion that is not used in digestion. These procedures then rearrange the small intestine to connect to both stomachs (Adams et al., 2007). Gastric bypass procedures lead to significant reduced stomach volumes and change the physiological process of digestion. Gastric bypass procedures are typically used to treat morbid obesity and other related conditions. Gastric bypass procedures lead to weight loss mainly the restriction of food intake (gastric restriction) but also as a result of malabsorption. This small amount of food that can be taken and following the surgery significantly reduces food intake and ingested food bypasses most of the stomach, the duodenum (this is the first part of the small intestine), and a small portion of the jenunum (second part of the small intestine). The bypass results in mild protein and fat malabsorption because there is a slight delay in the mixing of ingested food with pancreatic enzymes and bile (Tice, Karliner, & Walsh, 2008). These procedures have been demonstrated to reduce mortality rates due to obesity significantly (Adams et al., 2007). However, there can be several significant complications from gastric bypass surgery. For example Tice et al. (2008) indicated that up to 15% of patients experienced some complications as a result of gastric bypass surgeries.

A malabsorption syndrome is one of a number of conditions whereby the nutrients from food eaten are not absorbed adequately into the small intestine (DeMaria, 2007). Normally food is eaten and digested and nutrients are absorbed into the bloodstream in the small intestine; however, a malabsorption disorder or the effects of surgery such as a gastric bypass procedure can disrupt the absorption of food in the bloodstream. There are three categories of malabsorption: (1) selective malabsorption, where certain nutrients are not absorbed; (2) partial malabsorption, where the absorption of certain vitamins and other nutrients is not complete; and (3) total malabsorption. The malabsorption in gastric bypass surgeries consists of a combination of both selective and partial malabsorption.

The deficiencies associated with malabsorption syndrome and gastric bypass surgery typically clued deficiencies in iron, calcium, B vitamins such as vitamin B12, folate, some deficiencies of the fat-soluble vitamins (A, D, E, and K), and protein (DeMaria, 2007). Anemia and vitamin B12 deficiencies can be quite common following gastric bypass procedures if these vitamins are not supplemented. Despite potential applications from malabsorption syndrome the majority of studies have indicated that many of the health issues related to severe obesity such as diabetes and cardiovascular problems are alleviated following gastric bypass procedures in most patients (e.g., Marsk, Jonas, Rasmussen, & Naslund, 2010). Nonetheless, there have not been a good number of long-term follow-up studies that have suggested that problems with malabsorption may affect gastric bypass patients over the long run.

Becker, Balcer, and Galetta (2012) discuss a number of potential neurological complications that can occur following bariatric surgery. These neurological complications can potentially occur as a result of nutritional deficiencies due to malabsorption syndromes produced by gastric bypass surgeries. Polyradiculoneuropathy (a syndrome that resembles Guillain-Barre syndrome) and encephalopathy (brain related syndromes) can be acute manifestations of vitamin B1 deficiencies and thiamin deficiencies. A particularly troubling syndrome known as Wernicke’s encephalopathy may occur as a result of malabsorption syndromes associated with bariatric surgery. Long-term effects of thiamine deficiencies and untreated Wernicke’s encephalopathy can lead to irreversible dementia. More late appearing symptoms such as myelopathy, myopathy, and peripheral neuropathies can be associated with certain B, E, and mineral deficiencies. Optic neuropathy can be associated with mineral and vitamin B12 deficiencies and have been reported to be present one to three years following bariatric surgery (Becker et al., 2012).

If malabsorption is a mechanism by which gastric bypass surgery results in weight loss the patients that have this procedure it can also be expected to be at risk for a significant number of malabsorption syndrome neurological disorders. In addition, it would be expected that these neurological syndromes would be more prevalent in a sample of gastric bypass patients studied over time than in the general population. The current study suggests that a long-term follow-up study of gastric bypass patients and the prevalence of nutritional deficiency related neurological complications in these patients would be higher than is observed in the general population even if gastric bypass patients received nutritional supplements. Such a longitudinal study should cover a sufficient time period following the surgery in order to determine these trends. In addition, archival research could be used to look back at the histories of previous gastric surgery bypass patients and their neurological complications compared to a control group in order to determine if the these patients experience more complications than normal controls.

References

Adams, T.D., Gress, R.E., Smith, S.C., Halverson, R.C., Simper, S.C., Rosamond, W.D.,

LaMonte, M.J., Stroup, A.M., & Hunt S.C. (2007). Long-term mortality after gastric bypass surgery. New England Journal of Medicin, e 357, 753-761.

Becker, D.A., Balcer, L.J., & Galetta, S.L. (2012). The neurological complications of nutritional deficiency following bariatric surgery. Journal of Obesity, 2012, 1-8.

DeMaria, E.J. (2007). Bariatric surgery for morbid obesity. New England Journal of Medicine,

356, 2176-.2183.

Marsk, R., Jonas, E., Rasmussen, F., & Naslund, E. (2010). Nationwide cohort study of post-gastric bypass hypoglycaemia including 5,040 patients undergoing surgery for obesity in 1986 — 2006 in Sweden. Diabetologia 53, 2307 — 2311.

Tice, J.A., Karliner, L., & Walsh J. (2008). Gastric banding or bypass? A systematic review comparing the two most popular bariatric procedures. American Journal of Medicine, 21(10), 885-893.