Gastric Bypass Nutritional Consequences

April 6, 2015 | Dr. Linda J. Dobberstein, DC, Board Certified in Clinical Nutrition

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 Gastric Bypass Nutritional Consequences
America is a society of quick fixes, immediate gratification, processed foods, toxins, sedentary lifestyles and high stress. These factors, and so much more, play a role in the development of morbid obesity. Out of desperation, many individuals contemplate and follow their physician’s recommendation having some type of gastric bypass/bariatric surgery to reduce the problems with weight management, cholesterol, blood pressure, and other complications of obesity. If you are considering weight loss surgery or have already undergone a procedure, it is imperative to understand the long-term nutritional consequences.

The development and evolution of gastric bypass surgery started in 1966 following surgical intestinal bypass development and practice. In the nearly 50 years since its entrance and refinement as a treatment for morbid obesity, it has certainly gained popularity as the country struggles with the obesity epidemic. What follows here is a discussion of some of the known nutritional deficiencies that develop after bariatric/obesity surgery.

Different types of surgery may be more problematic than others in terms of its nutritional consequences. Every patient who goes through gastric bypass surgery is routinely medically monitored for several months and then yearly after the procedure. Dietary counseling is part of the initial aftercare with recommendations to take daily prescribed vitamins and minerals. But as the years go by, it is easy to become less diligent about this needed ongoing necessity. It is crucial to understand that once the procedure has been done, quality nutritional supplementation must occur because of the permanent compromised changes of the digestive tract and the reduced intake of nutrients. This now becomes a serious primal need that must be managed diligently and of a disciplined nature. If this is not followed, then long-term nutritional deficits occur. The nutritional deficits have widespread effects in the body further damaging healthy aging.

NIH Nutritional Guidance

The National Institutes of Health brochure on bariatric surgery provides minimal explanation of nutritional complications related to surgery. Their document states “as a nutritional side effect from not taking their prescribed multiple vitamins and minerals and not addressed promptly, (nutritional) diseases may occur along with permanent damage to the nervous system. These diseases include pellagra (lack of vitamin B3/niacin), beri beri (lack of B1/thiamin, and Kwashiorkor (lack of protein).” It does not take into account dozens of other nutrients that are often severely lacking. These three listed nutritional diseases are the result of extreme deficiency of these nutrients. By the time, a person reaches the disease state of pellagra, beri beri and Kwashiorkor, the severe nutritional deficits have been in place for several months if not years causing tissues to be at end stage function, i.e. severe permanent tissue damage. The seriousness of inadequate nutritional needs caused by bariatric surgery must be fully grasped and extensively explained to the patient.

Nutritional Deficits and Adverse Consequences after Bariatric Surgery

Relatively early on in the management and observation of nutrient deficits induced by bariatric surgery, the American Journal of Clinical Nutrition in 1980 reported nutritional deficiencies and problems identified after the jejunoileostomy. This is an older type of surgery that affects the small intestine for obesity management. This form of surgery provoked vitamin D deficiency, kidney stone formation, problems with fat digestion and fatty loose stools (steatorrhea), gallstones, zinc and copper deficiency and kidney failure.

A 1983 study found that half of the patients studied after gastric bypass were malnourished. There was an imbalance with electrolytes, i.e sodium and potassium and significant deficiencies with vitamin B12, thiamin/vitamin B1, and folate that commonly present with symptoms of weakness, easy fatigability, and lethargy. Many of these malnourished patients had to endure additional surgery to enlarge the bypass opening to allow more food to pass thru to reduce the complications of nutritional deficits.

In more extensive retrospective studies, we see additional nutritional deficits. In 2014, a meta-analysis study found that there was a decrease in copper, zinc, and hemoglobin and an increase in iron regardless of the type of obesity management surgery.

Another 2014 study admitted that there is alarming and increasing evidence of severe nutritional and pharmacological consequences of bariatric surgery. This study looked at research published from January 1980 through March 2014. The results are certainly worrisome for the patient. Results of this meta-analysis clearly showed that macronutrient (protein, fats, and carbohydrate) and micronutrient deficiencies are nearly universal after obesity surgery. The most critical was lack of albumin (hypoalbuminemia), and severe deficiencies of vitamin B1/thiamin (about 49%), vitamin B12 (about 19-35%), vitamin D (25-73%), iron (17-45%) and zinc (12-91%). Medication function often changes as well because of the change in digestive structure and function. Other studies find that there is a lack of calcium, magnesium, and vitamin A.


Understanding what some of these nutrients do can help a person understand the consequences of when there is a problem. Albumin is the main protein found in blood plasma produced by the liver. A fundamental purpose of albumin is to keep fluids in the proper balance and from leaking out of the blood vessels, i.e. fluid homeostasis. Albumin also transports water, electrolytes, fatty acids, hormones, bilirubin, and thyroid hormones to its destination. It also binds to toxins and heavy metals helping clear them out of the body. Low albumin levels compromises transport of these compounds and processes, profoundly shutting down healthy function. Low levels cause fluid retention in legs, lungs, and abdomen and poor function of electrolytes, hormones, and fats. Inadequate albumin is like having satellite signals and cell phone towers out of commission. The signals will be present, but nothing is going to carry the signals to where they need to go. It’s a threatening problem to all body functions.

Vitamin B1

One of the most common nutrient deficits seen after bariatric surgery is lack of thiamin/ vitamin B1. If this nutrient deficit is missed, it creates serious neurological problems with chronic complications with memory, cognitive skills, and gait/walking difficulties. Forgetting appointments, trouble balancing the checkbook, subtle changes in handwriting, and frequently bumping into things are neurological symptoms that can easily be dismissed as getting older, just being clumsy, or too tired. Yet these are early symptoms of brain distress. When it happens continually and progressively to the point of significant loss of function due to lack of vitamin B1, it is known as Wernicke’s encephalopathy.

Other types of neurodegenerative disorders, including Alzheimer’s disease are affected by insufficient thiamin intake. Researchers show that severe B1 deficiency is often prevalent before and after the surgery. It is critical to the body for the breakdown of all carbohydrates turning the fuel into energy. Simply being proactive with a quality multiple vitamin or a full B complex supplement on a daily basis can pre-empt many devastating consequences related with thiamin insufficiency.

Vitamin D

Vitamin D status prior to and after obesity surgery is another immensely important subject. Obesity problems are inversely related with lack of vitamin D, i.e. the worse the vitamin D status, the worse the problems with obesity. Bariatric surgery often worsens that status of vitamin D because of the disrupted digestive process. The immediate consequences are problems with secondary hyperparathyroidism and bone loss. It can easily develop into problems with metabolic bone disease. This is severely detrimental to pediatric patients going through this surgery as they have a lifetime ahead of them that requires healthy bones not just as structure but for metabolism too. Vitamin D is involved with over 1200 gene signals and is needed by every single cell in the body to function.

Pediatric Bariatric Surgery

With the obesity epidemic, bariatric surgery is being offered to morbidly obese pediatric patients. Adolescents are eligible to consider and have bariatric surgery after only a six month attempt at weight loss without success. Initial studies point to benefits with weight reduction, type II diabetes, dyslipidemia, sleep apnea, etc., but researchers clearly admit that there is no long-term data on safety and sustainability. It seems to be a rather foreboding experiment on the lives up our upcoming generation. A 2008 review study on children (average age 16.8 years) who had gone through bariatric surgery had serious problems with nutrient deficiency and severe malnutrition. Problems with band slippage and micronutrient deficiency were the most frequently reported complications, with sporadic cases of band erosion, port/tube dysfunction, hiatal hernia, wound infection, and pouch dilation. More severe complications have been documented, such as pulmonary embolism, shock, intestinal obstruction, postoperative bleeding, staple line leak, and severe malnutrition.

Young female patients undergoing this surgery especially need to think about the long-term consequences for their child-bearing years. Lack of folate and B12 is enough to cause serious birth defects or miscarriages, but what about the whole picture with multiple nutrient deficits. What is the next generation being set up with? What kind of lifelong challenges will they face? A young adolescent girl going through bariatric surgery and how she cares for herself will affect her offspring’s health for the next two generations because of the nutritional health of the DNA of the eggs in her ovaries. Any one of these deficits can easily compromise the health of that unborn child in pregnancy, but also throughout life as the genetics of the child develop. These are immensely sobering thoughts and probably not brought up and truly comprehended to the 16 year old looking at some type of obesity surgery.

Pre-surgery Nutritional Deficits

Nutritional health prior to obesity surgery showed numerous challenges as well, that can certainly put health further at risk on many different levels. A review article found multiple nutrients that were severely deficient in those who were in their pre-operative evaluations. Not surprising is severe deficiency in thiamin/vitamin B1. Vitamin B1 is integral to the process of burning glucose to make ATP. Any time you eat a carbohydrate, i.e. both complex and simple, fruits, veggies, grains, processed foods, you must have enough thiaminand its team player magnesium in order for it to work. Without it, there are problems with blood sugar function and management resulting in type II diabetes, dyslipidemia, fluid retention, etc.

Other severe nutritional deficiencies that were noted prior to obesity surgery included vitamin D, selenium, zinc, B12, iron, phosphorus, calcium, copper, and prealbumin. Keep in mind these results focus traditional medical lab tests used to measure nutritional status tests for basic deficiencies. When these values are lab level low, there is a severe deficiency present. In most cases, these labs do not reflect the optimal or functional amount needed to meet the daily demands of stress, genetic needs/polymorphisms, receptor site difficulties, etc. When these nutritional elements are measured low on a basic blood test, your tissue stores are in debt with no reserves. Your bank account is running on fumes. Nutritional dysfunction is present and pathological function is knocking on the door. These types of nutrient deficits and consequential tissue injury can be very difficult to recover from and repair. It is absolutely vital to address these nutrient deficits to avoid catastrophic consequences.

Other Concerns with Bariatric Surgeries

Patients undergoing bariatric surgeries and recovering from them face an onslaught of potential complications. Studies show early postoperative complications following gastric bypass that demand immediate recognition include anastomotic or staple line leak, postoperative hemorrhage, bowel obstruction and incorrect Roux limb reconstructions. Later complications include other gastrointestinal disorders, anastomotic stricture, marginal ulceration, fistula formation, weight gain and nutritional deficiencies.

Also disconcerting is the presence of increased gut permeability or Leaky Gut Syndrome after bariatric surgery. Not everyone experiences it as described in the studies, but it is a known adverse risk and effect. Increased intestinal permeability or Leaky Gut Syndrome is associated with a host of difficulties compromising multiple avenues of health even further. I suspect that the last thing that most patients think about are the long-term daily battles of nutritional deficiencies and poor digestive function after they go through the trauma of the surgery and the enormity of decisions they are trying to navigate through.


In summary, these are the known nutrients found to be frequently severely deficient after gastric bypass especially when poorly managed. Vitamins A, D, K, B1, and B12, folate, zinc, copper, iron, sodium, potassium, calcium, magnesium, hemoglobin, albumin, proteins/amino acids, fats, and carbohydrates. I suspect that there are other nutritional deficits not identified or recognized at this time. Lack of these nutrients will affect the brain, mitochondria, heart, detoxification, liver, bone, immune, endocrine, pancreas, insulin, blood, muscle, thyroid, adrenals, skin, and DNA/RNA – essentially every process in the body. What we put into our body or lack of determines disease and genetic expression.

It is crucial to meticulously provide quality nourishment and supplementation for life after any obesity management surgery. Ideally, the management of nutritional health would also occur prior to such drastic surgical interventions to prevent nutritional disasters and help recover if surgery is still chosen.

These types of surgeries are not readily reversible in most circumstances. The factors that brought the individual to that point of bariatric surgery are multi-level and complicated at the least. If you or someone you know has gone through something like this, you have to pull double duty lifelong with your nutritional support. This means that not only do you have to deal with the nutritional needs that we all face associated with basic life and its daily stressors and other illnesses or disorders that demand support, but you have the altered mechanics and change in function that you have to diligently take care of every day for the rest of your life. It gets complicated, weary, and difficult, but it has to be consistently supported for the years and years to come of your life otherwise the body will falter.

For those who struggle with weight management and haven’t reached the point of obesity surgery, get help. Quick impulsive decisions or giving up and resorting to drastic decisions are often dangerous. Surgery is surgery no matter how well it is talked up. Learn to make different choices. Learn about the hormone leptin and Mastering Leptin. Learn about gut inflammation and the gut microbiome, cortisol imbalances, improving sleep, toxins and detoxification, fatty liver problems, chronic infections, food intolerances, blood sugar management, 24 hour rhythms, artificial sweeteners, GMOs, and so much more. These are all involved in weight management. There is never one single magic bullet that works for obesity concerns. Managing calories and exercise is important, but it is far more than calories in, calories out, and exercise. Get help and become empowered with knowledge!

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