Dietary Issues after Bariatric Surgery

July 18, 2008

flintstones.jpgCommentary by Melissa Freeman MD, Endocrinology Section Editor

A new outpatient Bariatric Surgery Clinic recently opened at Bellevue Hospital Center. This clinic offers laparoscopic adjustable gastric banding to patients 18 years of age or older who meet specific BMI and medical criteria. This life-altering surgery is now covered by Medicaid and those who are uninsured can work with financial counselors to obtain funding through special HHC programs. While the surgeons diligently educate their patients on their dietary transitions and requirements after surgery, primary care physicians, amongst other issues after bariatric surgery, should be aware of the risk of nutritional deficiencies that these patients face.

After roughly one month postoperatively, patients begin their transition diet from liquid to a soft, solid diet as they learn to tolerate larger, richer food boluses. A significant focus is placed on chewing quality and pattern at this time. Eating habits of patients who undergo bariatric surgery vary somewhat based on whether they undergo gastric bypass or banding. Those who undergo gastric banding quickly learn to monitor their portion sizes and some may experience food aversions secondary to extensive vomiting. For patients who undergo gastric banding, the transition is more subtle. The initial band that is placed is actually deflated at first and then gradually tightened in 4-6 week intervals during the first 1- 2 years after surgery.

Patient’s who undergo any type of bariatric surgery are at increased risk of nutritional deficiencies as a result of drastic changes in food intake, altered digestive anatomy, and possible persistent vomiting. Common deficiencies include those of fat soluble vitamins, folic acid, and thiamine. Patients that undergo gastric bypass surgery are at a much higher risk of these deficiencies when compared to those that undergo gastric banding due to the varying operative procedures. For example, since food does not pass through the calcium transporter-rich duodenum in these patients, a calcium deficiency may occur. If combined with insufficient Vitamin D intake, secondary hyperparathyroidism can result. Patients who undergo gastric bypass also suffer more deficiencies of iron, Vitamin B12, and fat soluble vitamins. Though recommendations are somewhat limited, in general, vitamin supplementation in patients undergoing bariatric surgery (more specifically gastric bypass), should include a daily multivitamin (vitamins C, vitamin K, vitamin A, 800 IU vitamin D , E, B vitamins) in either pill or liquid form, monthly injections of vitamin B12 or sublingual B12 1000-2000 mcg daily, daily calcium supplements, iron (if at risk or a deficiency is present), and daily thiamine (if suffering from persistent vomiting).

In short, as bariatric surgery becomes available to more of our patients, primary care physicians should be aware of dietary issues and the potential for nutritional deficiencies in this demographic, especially those undergoing gastric bypass (which is not currently available at Bellevue). Physicians caring for these patients must assure that the appropriate labs are periodically checked to evaluate for any such deficiencies and vitamin supplementation should follow if necessary.

1. Bariatric surgery clinic opens at Bellevue Hospital @, posted 4/3/08, accessed 5/5/08.

2. Boan, J., Mun, E. Management of patients after bariatric surgery @, accessed 5/5/08.

3. Schweitzer, D., Posthuma, E. Prevention of vitamin and mineral deficiencie after bariatric surgery: evidence and algorithms. Obesity Surgery, 2008.

One comment on “Dietary Issues after Bariatric Surgery

  • Avatar of Dan
    Dan on

    Thoughts about Obesity

    Obesity is when excess body fat accumulates in one to where this overgrowth makes the person unhealthy to varying degrees. Obesity is different than being overweight, as it is of a more serious concern. As measured by one’s body mass index (BMI), one’s BMI of 25 to 30 kg/m is considered overweight. If their BMI is 30 to 35 kg/m, they are class I obese, 35 to 40 BMI would be class II obese, and any BMI above 40 is class III obesity. Presently, with obesity affecting children progressively more, the issue of obesity has become a serious public health concern.
    Approximately half of all children under the age of 12 are either obese are overweight. About twenty percent of children ages 2 to 5 years old are either obese are overweight. Worldwide, nearly one and a half billion people are either obese or overweight. In the United States, about one third of adults are either obese or overweight. It is now predicted that, for the first time in about 150 years, our life expectancy is suppose to decline.
    Morbid obesity is defined as one who has a body mass index of 30 kg/m or greater, and this surgery, along with the three other types of surgery for morbid obesity, should be considered a last resort after all other methods to reduce the patient’s weight have chronically failed. Morbid obesity greatly affects the health of the patient in a very negative way. It has about 10 co-morbidities that can develop if the situation is not corrected. Some if not most of these co-morbidities are life-threatening.
    One solution beneficial in many cases of morbid obesity if one’s obesity is not eventually controlled or corrected is what is known as gastric bypass surgery. This is a type of bariatric surgery that essentially reduces the volume of the human stomach in order to correct and treat morbid obesity by surgical re-construction of the stomach and small intestine. Patients for such surgeries are those with a BMI of greater than 40, or a BMI greater than 35 if the patient has comorbidities aside from obesity. This surgery should be considered for the severely obese when other treatment options have failed.
    There are three surgical variations of gastric bypass surgery, and one is chosen by the surgeon based on their experience and success from the variation they will utilize. Generally, these surgeries are either gastric restrictive operations or malabsorptive operations. Over 200,000 gastric bypass surgeries are performed each year, and this surgery being performed continues to progress as a suitable option for the morbidly obese. There is evidence that this surgery is particularly beneficial for those obese patients that have non-insulin dependent Diabetes Mellitus as well.
    So the surgery to correct morbid obesity greatly limits or prevents such co-morbidities associated with those who are obese. Two percent of those who undergo this surgery die as a result from about a half a dozen complications that could occur. However, the surgery reduces the overall mortality of the patient by 40 percent or so, yet this percentage is debatable due to conflicting clinical studies.
    Age of the patient should be taken into consideration, as to whether or not the risks of this surgery outweigh any potential benefits for the patient who may have existing co-morbidities that have already caused physiological damage to the patient. Also what should be determined by the surgeon is the amount of safety, effectiveness, and rationale for a particular patient regarding those patients who are elderly, for example.
    Many feel bariatric surgery such as this should be considered as a last resort when exercise and diet have failed for a great length of time.
    If a person or a doctor is considering this type of surgery, there is a website dedicated to bariatric surgery, which is:,

    Dan Abshear


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