B12 & Complex B Deficiency: Symptoms, Causes & Treatments

October 19, 2016

Weight loss surgery patients undergo a dramatic change in lifestyle following surgery.  While many of the changes are for the good, there are several things that can be onerous.  I have heard several patients complain about taking daily vitamins stating that while not difficult, it is annoying.  Sometimes it is hard to convey how important such a simple thing is especially when it is a bit bothersome.

Consequences of B12 & Complex B Deficiency

A few years ago, a patient from our clinic had a gastric bypass surgery and subsequently moved to a different state.  She recounted that as she established care with a new primary care physician, she was instructed to stop taking her vitamins which were referred to as unnecessary and a waste of money.  Shortly thereafter, she began to experience a strange tingling in her toes and fingertips.  This seemed to get progressively worse over time.  She began to notice that her legs were feeling heavy and she had begun to stumble frequently when walking.

Her PCP, who wanted her to go see a neurologist and did not seem to know what was going on, she finally called our office.  After hearing about her symptoms, we expressed our concern that this could be a long-term complication related to her surgery.  She decided to get on a plane and return to our clinic for evaluation. After a thorough exam and some laboratory work, we determined that her thiamine, or B1 level, was alarmingly low and in conjunction with her symptoms was diagnostic for a condition known as Beriberi Syndrome.

We began intensive vitamin replacement and within days, most of her symptoms had improved significantly.  Once her vitamin levels had normalized, we put her back on her normal daily post bariatric surgery vitamins. Fortunately, she had a complete recovery, but it took approximately a year before her sensation had completely returned to normal. The woman was fortunate, mainly because of her own initiative, that she was able to get treatment early and have a complete recovery.  Not all patients who develop neurologic symptoms as a result of low B complex vitamin levels do.

Other Symptoms of B12 Deficiencies

As with most medical conditions, there is a spectrum of effects that can result from B vitamin deficiencies.  Not all people who have deficiencies experience all of the symptoms or even the same symptoms as someone else.  The symptoms we watch for usually begin subtly with fatigue, anemia or low red blood cell count, tingling in fingertips and toes, depression, mild weakness and loss of coordination mainly in the lower limbs.  If left untreated, these symptoms will get progressively worse leading to falls or other accidents related to weakness and loss of dexterity.  People may also begin to have central nervous system effects such as impaired vision, poor memory, and even personality changes.  Finally, if left unchecked, they can develop severe weakness, spasticity, severe cramping, paraplegia, fecal and urinary incontinence, and potentially fatal cardiac arrhythmias.

In addition, they may have severe mental status changes such as dementia, mania, psychosis, loss of responsiveness, or even coma. Many of these quite severe symptoms are representative of known deficiency syndromes like Beriberi, Subacute Combined Degeneration, or Wernicke-Korsakoff and are often not completely reversible. Based on outcome studies of patients treated for Wernicke syndrome, up to 60% had residual visual symptoms; 60% had residual ataxia or slow, wide-based gait; and 80% had residual learning and memory deficits.

WLS Patients and B12 Deficiencies

The reason weight loss patients are susceptible to vitamin deficiencies is directly related to their surgery.

With B vitamins the problem lies in decreased absorption.  The absorption pattern is different for each vitamin, but the ones we are most concerned with are B1 and B12.  A percentage of the B12 that we ingest binds to a protein called intrinsic factor that is produced by acid-secreting cells in the stomach.  Then it travels down into the small intestine where it is later absorbed.  Many weight loss surgery patients have had their stomach bypassed or a significant portion removed.  As a result, the amount of B12 they consume has less intrinsic factor to bind to and ends up passing through the gastrointestinal system without getting absorbed.

The majority of B1 absorption occurs in the proximal small intestine.  In this region, there are specialized cells that allow passage of the vitamin into the body. In people who have had a gastric bypass or duodenal switch, food does not contact as much of the proximal intestine.  As a result, less of these specialized cells come in contact with the B1 we ingest leading to lower absorption. Fortunately, our bodies plan ahead (often better than we do) and most people have a vast store of B vitamins in their bodies.  As a result, B vitamin deficiencies can take months and even years to develop.

As with many medical issues, the best treatment is prevention.  Taking a daily multivitamin with thiamine (B1) and B12 is a simple and safe daily task that will drastically reduce the risk of any of these neurologic conditions. Even though the body’s ability to absorb B vitamins after surgery is reduced, taking supplements to increase the abundance of the vitamins ingested is almost always enough to overcome this and prevent deficiencies.

Deficiencies in patients who consistently take daily vitamins only occurs at a rate of approximately 3%.

In these rare cases when we detect low vitamin levels during annual check-ups or if patients begin to have any of the symptoms described above, we can give more direct supplementation via shots or nasal inhalants to treat and prevent further deficiencies.

Easy Way to Avoid B12 Deficiencies

B vitamin deficiencies are a rare phenomenon, but if left untreated can have severe and often irreversible effects on sensation, coordination, mentation, and even personality.  After weight loss surgery, people are more susceptible to developing these vitamin deficiencies.  Fortunately, there is a simple and easy way to avoid these problems:  take daily vitamin supplements.  This will successfully prevent 97% of patients from ever dropping below normal levels.  Clinical follow-up is important for early detection and treatment should deficiencies occur, but these are easily managed with more direct supplementation.



Nicholas Paulk, MD, FACS specializes in bariatric surgery for the treatment of obesity and weight-related conditions at Rocky Mountain Associated Physicians in Salt Lake City, Utah. As a board certified general surgeon and Fellow of American College of Surgery, Dr. Paulk offers patients lifesaving operations to live a better, more healthy and active life. It is a privilege to be part of such a positively life altering endeavor that is bariatric surgery.

Read more articles by Nicholas Paulk, MD, FACS