Unique Brain Activity After Successful Weight Loss Surgery

Unique Brain Activity After Successful Weight Loss Surgery:

By Rob Goodier

NEW YORK (Reuters Health) Jun 25 - Differences in brain activation at the sight of food may explain why some patients do better than others after bariatric surgery, new research suggests.

The study, presented June 21st at the annual meeting of the American Society for Metabolic and Bariatric Surgery in San Diego, showed that gastric bypass patients who lose 50% or more of their excess weight had unique neural responses to images of food.

The brains of these successful patients showed more activation of the prefrontal cortex on functional magnetic resonance imaging in response to food cues.

"We're seeing an increase in activation in areas that correspond to planning and decision making," Dr. Rachel Goldman, who led the study at the New York University School of Medicine and Bellevue Hospital Center, told Reuters Health.

In the study, 40 patients submitted to fMRI scans one to five years after gastric bypass. Twenty-seven were considered successful and had lost an average of 71.9% of their excess weight. The 13 unsuccessful patients had lost 41.6% of their excess weight.

While in the scanner, the patients looked at a random mix of pictures of food and neutral images. They first allowed themselves to crave the food, then in a separate round they tried to resist the craving.

While craving, the successful patients displayed more activity in the left prefrontal cortex, insular cortex, putamen, anterior cingulate, posterior cingulate and the supramarginal gyrus compared to the other patients.

While resisting their cravings, the successful patients again had more activity in the left prefrontal cortex.

The unsuccessful patients, on the other hand, showed more activity in the posterior cingulate and precuneous regions while trying not to crave. Those regions are associated with emotion and anticipation of reward.

Dr. Jennifer Lundgren, an associate professor of psychology at the University of Missouri-Kansas City who was not involved in the research, told Reuters Health by email that the new findings "are consistent with other fMRI studies showing increased activation in brain regions associated with cognitive control and inhibition after weight loss by both surgical and non-surgical means."

"Those who lose less weight after surgery may find food more rewarding or have increased emotional response to food cues, compared to those who are more successful with weight loss," Dr. Lundgren said.

Both she and Dr. Goldman raised the possibility of a future test for patients before surgery to better predict outcomes. That may be one of Dr. Goldman's targets for future research.

"If preoperative neural imaging can identify the success of surgery, maybe that would tell us if the individual already has the necessary activation of the brain to be successful," Dr. Goldman said. "Or maybe there's something going on after surgery that changes the brain activity - an interaction between the surgery and the brain activation. Another area (for study would be whether) cognitive or brain interventions could change that."

In the meantime she speculates that interventions such as mindful meditation or even transcranial direct current stimulation could someday improve weight loss in gastric bypass patients.

 From Medscape

Race Might Play Role in Success of Weight-Loss Surgery

Black women lost less than whites, but the gap was narrower when diabetes was present, study finds

WEDNESDAY, June 20 (HealthDay News) -- Black women without diabetes lost about 10 percent less weight than white women after having a weight-loss procedure called gastric bypass surgery, but having diabetes helped increase their weight loss, a new study finds.

For the study, Duke University researchers compared outcomes among nearly 300 obese white and black women with an average age of 40 who underwent gastric bypass surgery, a procedure that makes the stomach smaller in order to help people lose weight.

Overall, black women lost nearly 57 percent of their excess weight in the three years after surgery; white women lost less than 65 percent. Black women with type 2 diabetes, however, lost about 60 percent of their excess weight, the investigators found.

Among women with diabetes, both blacks and whites had similar diabetes remission rates (75 percent and 77 percent, respectively) after the surgery, according to the study, which is scheduled for presentation Wednesday at the annual meeting of the American Society for Metabolic & Bariatric Surgery in San Diego.

"For some reason, diabetes was the great equalizer when it came to weight loss," study co-author Dr. Alfonso Torquati said in a society news release. "[Black] women with type 2 diabetes lost a similar amount of excess weight as [white] women. Racial differences in excess weight loss only emerged between non-diabetic women."

"Further study is needed to determine if the reasons are genetic or because of differences in body-fat distribution or both," said Torquati, director of the Duke Center for Metabolic and Weight Loss Surgery.

Although the study uncovered an association between having diabetes and greater weight loss after the surgery in black women, it did not prove a cause-and-effect relationship.

In addition, because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.

More than 23 million Americans have diabetes, with type 2 diabetes accounting for more than 90 percent of cases, according to the U.S. National Institutes of Health. Nearly 13 percent of black Americans have diabetes, compared with about 7 percent of whites, according to the American Diabetes Association.

More information

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about weight-loss surgery.

-- Robert Preidt

SOURCE: American Society for Metabolic & Bariatric Surgery, news release, June 20, 2012

Bariatric Surgery is Associated With Increased Likelihood of Alcohol Problems

In full, from Medscape -

May 15, 2012 (Lyon, France) — Bariatric surgery is associated with an increased likelihood that patients will report and be diagnosed with problems related to alcohol consumption. Different levels of risk are associated with different gastric surgery procedures, Per-Arne Svensson, PhD, from the Sahlgrenska Center for Cardiovascular and Metabolic Research at the University of Gothenburg in Sweden, reported here at the 19th European Congress on Obesity.

Continued -

The nonrandomized prospective Swedish Obese Subjects (SOS) trial matched 2010 patients undergoing bariatric surgery in 25 surgical departments from 1987 to 2001 with 2037 contemporary control subjects. People who had alcohol problems at baseline or who consumed more than 34 g/day of pure alcohol (equivalent to 3 bottles of wine per week) were excluded from the study.

The treating surgeon determined the kind of surgery; 19% of patients underwent gastric banding, 68% underwent vertical banded gastroplasty, and 13% underwent gastric bypass surgery. At baseline, the mean ages in the 3 surgery groups and in the control group were 47.0 to 48.7 years (range, 37 to 60 years), and mean body mass indices were 40.1 to 43.9 kg/m². There were no differences in alcohol-related parameters in the groups.

Previous results from the SOS study showed that gastric bypass produced the greatest long-term weight loss, and that gastric banding and vertical banded gastroplasty produced similar degrees of weight loss. It has also shown that alcohol consumption decreases in the first 6 months after gastric bypass, but subsequently increases.

Dr. Svensson and colleagues assessed the long-term changes in alcohol consumption and abuse after bariatric surgery. Median follow-up time was 10 years. Alcohol consumption was self-reported for the previous 3 months, and alcohol problems were self-reported at progressively longer time intervals after surgery. Data on diagnosed alcohol abuse came from a national register, according to International Classification of Diseases codes (ICD-9 and ICD-10).

The World Health Organization defines medium-risk alcohol consumption as 40 g/day for men and 20 g/day for women. Men and women in the control and bariatric surgery groups, as a whole, were well below these respective levels.

"During the first year, we actually see a reduction in alcohol consumption," which is similar to what has previously been reported, Dr. Svensson said. "But things change over time."

For men, median alcohol consumption in the gastric bypass group increased. However, because of individual variation in the groups, the researchers looked at the cumulative incidence of the alcohol-related parameters.

Medium-risk alcohol consumption was greatest with gastric bypass (about 14% at 10 years and 20 years for men and women combined, compared with about 5% in the control group). Self-reported alcohol problems and alcohol abuse diagnoses were also greatest with gastric bypass. For vertical banded gastroplasty, the incidence of medium-risk alcohol consumption fell between the gastric bypass and control groups. For gastric banding, the incidence did not differ significantly from that in the control group.

Adjusted Hazard Ratios, Compared With Control Group (95% Confidence Interval)*

Type of Surgery	Medium-Risk Alcohol Consumption	Self-Reported Alcohol Problems	Diagnosed Alcohol Abuse
Gastric bypass	5.91 (3.40–10.39)	2.69 (1.58–4.57)	4.97 (2.70–9.15)
Vertical banded gastroplasty	1.52 (1.09–2.11)	2.30 (1.45–3.66)	2.23 (1.38–3.59)
Gastric banding	1.22	1.44	1.57

*All values statistically significant at P < .05, except for gastric banding.

Possible mechanisms contributing to the alcohol abuse are the faster transport of alcohol to the small intestine and the reduced first-pass metabolism of ethanol by alcohol dehydrogenase in the stomach, leading to higher peak blood alcohol levels after gastric bypass surgery, and alterations in gastrointestinal hormones. Dr. Svensson speculated that there might also be "addiction transfer," in which alcohol addiction substitutes for food addiction.

He concluded that gastric bypass and vertical banded gastroplasty increased the risk for alcohol-related problems, with gastric bypass presenting the most risk. He suggested that healthcare professionals and patients be informed of these risks.

Luca Busetto, MD, from the Department of Medical and Surgical Sciences at the University of Padova in Italy, who was not involved in the trial, told Medscape Medical News that the potential for alcohol abuse after bariatric surgery has been known for many years, but that now we probably "have a more precise estimation of the numbers of the problem."

Dr. Busetto explained that in gastric bypass surgery, the pylorus is bypassed, "so the alcohol goes directly into the jejunum and is absorbed very rapidly. You may have a higher peak in alcoholemia after the same amount of wine," which can be a problem if someone is prone to alcohol addiction and experiences the effect of the consumed alcohol more rapidly. He said that studies have shown this faster absorption rate.

He noted that alcohol problems occur in a relatively small minority of patients. "It's a minor problem in comparison to the benefits [of surgery], but it's a problem that a doctor caring for patients with gastric bypass should be aware of," Dr. Busetto said.

In his experience, "in the first year after bariatric surgery, everything goes perfectly." Patients lose weight, are happy, attend all appointments, and follow the prescriptions — they are perfect patients. "After that, things change," he said. "So in bariatric surgery...you need to wait at least 5 years to have reliable results."

Commercial entities funding the study were Hoffmann La Roche, Cederroth, AstraZeneca, sanofi-aventis, and Ethicon Endosurgery. Dr. Svensson and Dr. Busetto have disclosed no relevant financial relationships.

19th European Congress on Obesity (ECO): Abstract 155. Presented May 11, 2012

Links to Studies about Post-Gastric Bypass Hypoglycemia or Hyperinsulinemia

Hypoglycemia or Hyperinsulinemia are getting more attention in post-gastric bypass patients. It is turning out to be more common than once thought. Below are the links to studies related to this issue. The link is followed by a snippet from the abstract (summary). 

Most of the links go directly to the abstract, rather than the full text. Often times, the full text of a more recent research study requires access to an academic library or to the journal itself. So, if you would like to read more than the abstract, ask your bariatric practitioner or maybe a friend who works at a college to if they would mind getting a copy of the full text for you.

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1) Hyperinsulinemic Hypoglycemia After Roux-en-Y Gastric Bypass: Unraveling the Role of Gut Hormonal and Pancreatic Endocrine Dysfunction

Profound hypoglycemia occurs rarely as a late complication after Roux-en-Y gastric bypass (RYGB). We investigated the role of glucagon-like-peptide-1 (GLP-1) in four subjects who developed recurrent neuro-glycopenia 2 to 3 y after RYGB.

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2) Abnormal glucose tolerance testing following gastric bypass demonstrates reactive hypoglycemia

Symptoms of reactive hypoglycemia have been reported by patients after Roux-en-Y gastric bypass (RYGB) surgery who experience maladaptive eating behavior and weight regain. A 4-h glucose tolerance test (GTT) was used to assess the incidence and extent of hypoglycemia.
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3) Glucagon Treatment for Post-Gastric Bypass Hypoglycemia
Hyperinsulinemic hypoglycemia is a rare complication of RYGB; its pathophysiology remains incompletely understood (1,3,4). These patients exhibit inappropriately high insulin and C-peptide concentrations during hypoglycemia (5,6). In addition, exaggerated insulin and incretin responses are observed during mixed meal tolerance test (5) and may contribute to hypoglycemia, potentially mediated in part by islet cell hyperplasia and/or altered function (1,4). Although most cases are mild and managed with dietary modification, symptoms can be profound and result in serious adverse consequences, and clinical management can be challenging. Treatment options include intensive dietary modification (6,7), α-glucosidase inhibitors, octreotide, and diazoxide (5,7). However, some patients remain refractory to treatment, and partial pancreatectomy has been undertaken, with varying success (4). Given the lack of efficacy of available interventions in some patients, and the goal of averting pancreatectomy, additional pharmacologic options are needed.

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4) Advances in the Etiology and Management of Hyperinsulinemic Hypoglycemia After Roux-en-Y Gastric Bypass      Treatment of hypoglycemia after RYGB should begin with strict dietary (low carbohydrate) alteration and may require a trial of diazoxide, octreotide, or calcium-channel antagonists, among other drugs. Surgical therapy should include consideration of a restrictive form of bariatric procedure, with or without reconstitution of gastrointestinal continuity. Partial or total pancreatic resection should be avoided.

Addiction Tip Sheet – Addiction and Weight Loss Surgery: A Social Worker’s Perspective « Helpstartshere.org

Here's an excellent article by Katie Jay about transfer addiction after bariatric surgeon. She does a very nice job of showing how this risk exists for WLS patients by telling one person's story. It's worth the read.

Addiction Tip Sheet – Addiction and Weight Loss Surgery: A Social Worker’s Perspective « Helpstartshere.org:

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Bariatric Surgery and Long-term Cardiovascular Events, January 4, 2012, Sjöström et al. 307 (1): 56 — JAMA

This is an excellent article from JAMA, related to the reduced risk of heart attacks and other cardiovascular events after WLS. Below is excerpt of the abstract, followed by the link to the study.

Results Bariatric surgery was associated with a reduced number of cardiovascular deaths (28 events among 2010 patients in the surgery group vs 49 events among 2037 patients in the control group; adjusted hazard ratio [HR], 0.47; 95% CI, 0.29-0.76; P = .002). The number of total first time (fatal or nonfatal) cardiovascular events (myocardial infarction or stroke, whichever came first) was lower in the surgery group (199 events among 2010 patients) than in the control group (234 events among 2037 patients; adjusted HR, 0.67; 95% CI, 0.54-0.83; P < .001).

Conclusion Compared with usual care, bariatric surgery was associated with reduced number of cardiovascular deaths and lower incidence of cardiovascular events in obese adults.

Here is the Link to the full story - -

Bariatric Surgery and Long-term Cardiovascular Events, January 4, 2012, Sjöström et al. 307 (1): 56 — JAMA:

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Why is it so Hard to Maintain a Reduced Body Weight? | Dr. Sharma's Obesity Notes

This is an excellent article explaining the role of leptin maintaining weight loss. As this article explains, formerly obese people burn about 20% fewer calories than people of the same weight who were never obese. This is not only because metabolism has been slowed by the obesity, but because the body perceives a drop in leptin and begins to hoard fuel (save calories) even while exercising. This is a very interesting read:

Why is it so Hard to Maintain a Reduced Body Weight? | Dr. Sharma's Obesity Notes:

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