According to the World Health Organization, in 2005 at least 400 million adults were obese. More than 300 million people in the world are considered obese, with a large number of these in the United States. Gastric bypass surgery is a weight loss surgery used to treat obesity. It is performed on patients who have tried and failed other, more conventional methods of weight loss such as diet and exercise.
Background
Typically, to qualify for gastric bypass surgery, you must have a body mass index (BMI) of greater than 40 or a BMI of 35 to 39.9 with other diseases, such as diabetes, high blood pressure or high cholesterol. The surgery is considered to be both restrictive and malabsorptive. This is because not only is the stomach size decreased significantly but the intestines are re-routed and nutrients are not absorbed as well as in a normal gut. Due to these changes, gastric bypass surgery is not for mildly obese or overweight individuals.
Nutritional Concerns
Due to the nature of the surgery, nutrition deficits in vitamins and minerals are major concerns. Malabsorption in the gut means that even with adequate food intakes, you are at risk of deficiencies. It is essential to follow the nutritional protocol of your surgical facility for optimal weight loss results and to ensure adequate nutrition. After surgery, you may be at increased risk of deficiencies in iron, calcium, vitamin B12 and thiamin.
Iron Deficiency
Iron is best absorbed in an acidic environment, such as the stomach, but after gastric bypass surgery, less stomach acid is produced, decreasing absorption. Typically, the majority of iron is absorbed in the duodenum, which is bypassed during surgery. A deficiency in iron can lead to anemia, leading to fatigue.
Calcium Deficiency
Calcium is essential in bone health and if you've had gastric bypass surgery, you are at greater risk of becoming deficient. Similar to iron, calcium is typically absorbed best in the duodenum, leading to decreased absorption after surgery. Without adequate intakes of calcium after surgery, you are at risk of developing osteoporosis down the road.
Vitamin B12 Deficiency
Vitamin B12 deficiency can occur after surgery due to its need for an acidic environment and a component in the stomach, the intrinsic factor, for absorption. After gastric bypass surgery, both of these are diminished, leading to a risk for deficiency. According to the American Gastroenterological Association, greater than 50 percent of patients are found to be deficient after surgery if not taking appropriate supplementation. Deficiencies, if severe, can lead to serious neurological problems.
Thiamin Deficiency
Thiamin is a B vitamin that is needed in metabolism and cellular functions in the body. Absorption of thiamin is best in the duodenum and, due to the bypass of this section during surgery, absorption is decreased after. Thiamin deficiency can lead to serious neurological damage and a disease called beriberi. According to Medline Plus, an online resource of the National Institutes of Health, if untreated, this disease could lead to death.
Conclusions
Gastric bypass surgery is not appropriate for all people, so consult your doctor to see if you qualify. After the surgery, you are at an increased risk of vitamin and mineral deficiencies, but adequate amounts of these nutrients through diet and/or supplementation can prevent complications that may occur. Consult your physician for recommendations for supplementation after gastric bypass surgery.
References
- American Gastroenterological Association Review on Obesity
- Einstein Bariatrics: Minerals and Vitamins
- Linus Pauling Institute at Oregon State University: Micronutrient Information Center Vitamin B12
- Linus Pauling Institute at Oregon State University: Micronutrient Information Center Thiamin
- Medline Plus: Beriberi
- World Health Organization: Obesity and Overweight
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