Junkfood Science: Losing more than expected

March 13, 2007

Losing more than expected

If you blinked, you may have missed this story in the news and its significance. Of the few papers and networks that did report on this latest study, the full scoop and decades of supportive medical literature weren’t included. Instead, by judicious choices of words and carefully selecting sources to quote, most reinforced popular misconceptions.

The Canadian Press gave one of the most objective reports of the latest study:

There’s a downside to obesity surgery

TORONTO — When people with obesity have surgery to help them lose weight, they can also lose something else — the ability to properly absorb certain nutrients, in particular vitamin B1. And that deficiency can potentially lead to permanent brain damage if left untreated, researchers say.

In a review of the medical literature, researchers at the Wake Forest University School of Medicine found 32 cases of bariatric surgery patients who developed symptoms of Wernicke encephalopathy, a condition marked by memory loss and confusion, an inability to co-ordinate movements and rapid eye movement. Wernicke's is caused by a deficiency in vitamin B1, also called thiamine, and these classic symptoms are usually seen in alcoholics, said lead author Dr. Sonal Singh, an internal medicine specialist at Wake Forest University in Winston-Salem, N.C.

“But interesting to our study, we found that these people also had other symptoms, like hearing loss, [muscle weakness], convulsions and tingling and numbness of the arms and legs — symptoms that have not been previously described with Wernicke's,” Dr. Singh said in an interview....

The risk of brain damager after bariatric surgeries is rarely reported in the news. This study was published in the current issue of Neurology, the scientific journal of the American Academy of Neurology.

While the exact numbers of patients who get the neurological disorder called Wernicke’s encephalopathy (WE) are unknown, it is considerably higher among bariatric patients than the general population and many researchers believe it is underreported and that the full impact is not yet recognized.

Dr. Singh reported that atypical symptoms of WE were actually common and cautioned that it was imperative for family members and doctors to recognize the symptoms and seek medical care immediately if anyone after bariatric surgery begins to have vomiting or other symptoms such as confusion, lack of coordination or visual changes. “Doctors should consider vitamin B1 deficiency and WE when they see patients with these types of neurological complications after weight loss surgery,” wrote Dr. Singh. Diagnosis for brain damage is not always evident on X-rays, he cautioned.

More than ten years ago, Jillian Kril, Ph.D., associate professor Department of Medicine and Pathology, University of Sydney, also noted that thiamine deficiency after bariatric surgery can be missed and that the presenting symptoms can appear subclinical. She reported in 1996 that such patients can also show irritability, tremors and shakiness, feeling cold, headaches and unusual fatigue. “WE is actually the most frequently encountered manifestation of thiamine deficiency in Western society,” Dr. Kril said.

The three classic symptoms of WE were first described in 1881 but only one-third of patients have all three, according to Dr. Philip N Salen, M.D., a clinical professor of emergency medicine at Desales University in Center Valley, PA. The classic symptoms are: altered mental states with loss of memory or cognition (encephalopathy) that can progress to psychosis (called Korsakoff psychosis); loss of coordination (ataxia); and uncontrollable eye movements (oculomotor dysfunction).

Concerns that most cases of WE are going unrecognized and that most bariatric programs do not routinely monitor for it, continue to be reported by multiple researchers. A review of the clinical signs of Wenicke published in the Journal of Neurology, Neurosurgery, and Psychiatry in 1986, found that 80% of patients had gone undiagnosed prior to their death. It was found on autopsy. The researchers noted that while most clinicians were aware of the high risk among alcoholics, most doctors were not aware it’s also common in conditions with malnutrition and after recurrent vomiting (pregnancy, cancers, AIDS, etc.), strict dieting, and gastric surgeries.

Autopsy research has placed the incidence of WE between 0.8% to 2.8% of the general population, Dr. Salen wrote, but it can be as high as 12.5% among alcoholics.

WE after bariatric surgeries has continued to be reported in the medical literature with growing frequency for decades. While the earliest reports of neurological damage after bariatric surgeries in the 1970s didn’t identify the specific cause, researchers were increasingly reporting confusion, slurred speech, and neurological complications in the 1980s. In a review, “The neurological complications of bariatric surgery,” neurologist Dr. Joseph R. Berger, M.D., Department of Neurology, University of Kentucky College of Medicine, Lexington, said that by the year 2000, there were at least 30 cases of WE in the medical literature. In his review, he concluded “neurological complications occurring in the setting of bariatric surgery are not uncommon [and] have been reported in as many as 5% to 10% of patients.”

A 2006 review of the medical literature found 50 case reports of 96 patients with neurological complications after bariatric procedures.

It is commonly and mistakingly believed that vitamin and nutritional deficiencies are rare risks after bariatric surgeries, and that they only occur after bypass procedures and not lap bandings. The Canadian Press article accurately reported that this study found WE occurring after all types of bariatric surgeries: bypass and banding procedures. This concurs with the body of medical literature and other studies, such as in a 2003 issue of Obesity Surgery, finding WE after gastric banding. The risks for WE also increase with vomiting and the LAP-BAND System U.S. clinical trials for FDA approval reported that 89% of patients had at least one adverse event. “The most commonly reported peri-operative adverse events were abdominal pain and nausea and/or vomiting.”

What may be surprising to many to learn is how quickly after surgery this specific neurological complication is seen: as early as six weeks after surgery, with most cases within the first three months. But WE has also been reported years after surgery. Thiamine is absorbed in the small intestine and isn’t stored in large amounts in any tissues of the body, making a continuous supply necessary on a regular basis.

According to Dr. Berger, the medical literature has also confirmed that it can occur despite oral supplementation with thiamine. Dr. Singh in this week’s study also noted that while some post-op patients who got WE had not been taking their vitamins (many due to vomiting), others got WE despite taking their prescribed supplements. This is in sharp contrast to common beliefs, most often promoted by the bariatric industry, that taking vitamins will prevent complications and that complications are due to noncompliant patients.

The Washington Post and HealthDay News reported, “Weight-Loss Surgery Caution: Take Your Vitamins,” and used a bariatric surgical program director and the immediate past president of the American Society for Bariatric Surgery as their source of information. Their report downplayed the risks and claimed it is “totally preventable and either completely or partially reversible” and that: “Taking the recommended dose of supplements after surgery can prevent the brain illness.”

Dr. Singh in this latest study also isn’t the only doctor expressing the urgency of this deficiency. “Wernicke encephalopathy must be viewed as a medical emergency, even if other competing diagnoses of CNS processes are being considered,” according to Dr. Salen and emergency medicine physicians. Neurologist Dr. Berger also specifically warned: “Physicians need to be particularly alert to Wernicke encephalopathy developing after bariatric surgery because it is a medical emergency and demands rapid diagnosis and intervention.”

Time is of the essence as thiamine deficiency is the most dangerous and has the greatest clinical importance of the vitamin deficiencies. Intravenous thiamine must be given immediately because delay can reduce the chance for recovery of neurological function. According to Dr. Salen, there is significant morbidity and mortality rates with WE and a significant number of those who develop Korsakoff psychosis never recover and will require long-term institutionalization. “Only about 20% eventually recover completely during long-term follow-up care.”

With bariatric surgeries being marketed more heavily than ever and surgeries among U.S. teenagers tripling just between 2000 and 2003, and skyrocketing 1100% since 1995 in adults, the impact of such complications on long-term health and healthcare has yet to be fathomed.

In this week’s study, of the 32 patients with WE, 13 made a full recovery, 18 were left with permanent neurological damage, and one patient, a 33-year-old woman, died. “Many people continued to have problems, such as memory problems, weakness or difficulty coordinating movement,” said Dr. Singh.

© 2007 Sandy Szwarc

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