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Nutritional Complications of Bariatric Surgery

I have been planning to do a supplements section in this blog. In fact, I want to do several blogposts on the topic of supplements, but the fact is, most  of these ‘supplement description and recommendation’ sections in books and blogs are rather boring unless they are placed in a context.

General laundry-listing can be interesting but it is no fun to read.  One of the main purposes of writing this blog, that I have always had, is to, along with being informative, create something that fun (and hopefully beautiful) to read. So, rather than talk about supplements I thought I would discuss nutritional complications after bariatric surgery. By doing this, I hope I will be able to inform you about  about some important vitamins and minerals that you may (and also, more importantly may not) want to take.

Now, first a little background about bariatric surgery.

I am no fan of bariatric surgery.  In fact, I am a pretty staunch critic of bariatric surgery, in light of what I have learned about  all of those toxic things like sugar, flour, and and processed food of your diet, which I think are the major sources of obesity in the modern world.

I personally see no reason to perform gastric bypass surgery for people who have not been, as of yet, been giving the proper tools and a fair chance to succeed with diet.  Most people are willing and sometimes desperate to lose weight.  Surgery has be the last resort, at best.

In fact, I think bariatric surgery should not be utilized at all. In my opinion, it just doesn’t make sense. If you eat healthy you should be healthy, and likewise, you can be both fat and healthy.  It’s not always the case, but it certainly does happen. Cutting and rearranging organs is not a cure for a bad diet.

In any case, there are two general types of bariatric surgeries: restrictive procedures and restrictive with malabsorption procedures.  Restrictive procedures referred to surgeries that make the stomach smaller specifically.  This category includes gastroplasty or stomach stapling.  Restrictive procedures with malabsorption refer to things that actually bypass parts of the intestine.  The most common of these procedures is called Roux-en-Y gastric bypass, it looks like this.

For me, I cannot see how on earth it is good over the long-term to disrupt the normal physiology of a patient who could otherwise lose a ton of weight and improve their health with the proper diet information and coaching.  Of course, I do not perform these procedures, but one thing I have known as a plastic surgeon is that when patients come for post bariatric body contouring, these are very hard cases to do. Specifically because it has been my observation  that the skin tissue and adipose tissue just does not seem like a normal person’s tissue.  It  appears very frail and weak and hard to deal with (what is called attentuated in medical terms).  It does not have that stability and resilience that the normal healthy tissue typically does, like healthy skin or fat issue on a lean person, it is tight, but of course these are just observations, and this has not been studied scientifically in detail, though.

In any case, I wanted specifically to talk about the vitamin and mineral deficiencies.


The first one I wanted to talk about is iron deficiency which is the most common deficiency in bariatric surgery patients, specifically in patients who have underwent a Roux-en-Y gastric bypass or a restricted procedure with malabsorption.  The incidence is as high as 50% Iron is important for the function of red blood cells, as it is what carries the oxygen in out blood to ur tissues, and as a result, chronic iron deficiency can cause chronic anemia.

Iron is present in foods in a form that is know as the ferric form and in order to be absorbed, it needs to be reduced to the ferrous state and this occurs in the stomach and it is facilitated by hydrochloric acid, which isn’t there if you have bypassed most of the stomach.

Likewise, many patients who undergo gastric bypass procedures or a similar malabsorptive procedure take post surgical histamine 2 blockers such as Pepcid or Prevacid, which prevent the stomach from making acid, and that too, can causes iron deficiency.

Foods that are typically rich in iron are animal products which, unfortunately, are very hard and difficult to digest after a Roux-en-Y gastric bypass.  People typically tend to subsist on a lot of liquid foods, which are obviously not meat milkshakes.

In the gastric bypass patients, it is noted that supplementation with a multivitamin alone is generally not enough.  You actually have supplement with actual ferrous sulphate 300 mg three times a day. This is what is generally recommended.  Sometimes patients will require IV iron supplementation.


Vitamin B12 is a very important vitamin that is involved in blood cell health, DNA health, and immune system health.  Once again, it relies on hydrochloric acid as well as pepsin (a stomach enzyme) to be absorbed.  As a result, 26 to 70% gastric bypass patients are noted to be deficient in vitamin B12, often this has to be supplement with intramuscular injections or nasal spray.


Many people have heard about folic acid because it is important in pregnancy, and pregnant women supplement with this vitamin in order to prevent spinal cord defects.  Folic acid deficiency is another nutritional complication of gastric bypass procedures specifically with malabsorption procedures such as Roux-en-Y gastric bypass and occurs in as many as 35% of patients.  Folate, unlike the other vitamins I have mentioned, is actually absorbed primarilyin the upper one-third of the small intestine.  What is interesting to note is that vitamin B12 is important in folic acid absorption because B12 is actually the co-enzyme in converting folate into an absorbable form.  So vitamin B12 deficiency and folic acid deficiency tend to go together.  If you lack folate, people develop complications such as megaloblastic anemia, thrombocytopenia, leukopenia, and glossitis.


Fat soluble vitamin deficiencies are actually quite rare in gastric bypass patients because vitamin D for instance is absorbed preferentially in the jejunum and ileum which are not bypassed. That being said, there have been reports of osteomalacia and bone problems after Roux-en-Y gastric bypass.  People generally have to supplement with vitamin D, and likewise, they also have to supplement with calcium.

Vitamin A is also deficient in many bariatric surgery patients.  The best source of vitamin A is high quality animal protein such as meats, eggs, and leafy green vegetables as well as colored vegetables such as carrots, which every one knows.  These are hard to digest after Roux-en-Y gastric bypass.  So, it needs to be supplemented, which is not as good as taking it as part of a whole food.


Thiamine deficiency, thiamine is also known as vitamin B1 and it is absorbed in the proximal small bowel.  Thiamine deficiency is associated with something called Wernicke-Korsakoff syndrome, which is a very interesting neurological condition which my wife knows a lot about with her being a neurologist.  It is actually seen in alcoholics quite frequently and it consists of memory loss and confabulation.  As I have said, it occurs mostly in alcoholics, but it has been seen also in gastric bypass patients.  It also needs to be corrected with an IV injection/infusion, much like B12.


These are the major nutritional complications after gastric bypass surgery.  Personally, it seems to me like a Faustian bargain to undergo gastric bypass surgery.  It is a forced malabsorption and weight loss through starvation.

As many of you know, I am very much a fan of a whole foods low sugar, low flour, no processed food dietary approach to weight loss,and I think it works in the majority of cases.

As a result I have been developing with my friend Geoff Pinkus I have been working on developing a man’s diet which is based a great deal on a paleolithic template/principles and tries to incorporate the average guy who is trying to lose weight. A guy who has a family and wants to be healthy and enjoys grand kids and see his kids graduate from college and not to have heart attacks or stents and be on blood thinners and diabetic medications for the rest of his life.

I do not think gastric bypass is the solution to get to those goals.

If you would like to share your thoughts and comments, please do not hesitate to comment on the blog section.  I would love to hear from you and I would love to learn from you if you have things to contribute.

If you would like to know more about The Man Diet Vitamin Pack 1.0 that I have developed, please feel free to contact me about it, and I can send you the information!

Remember to listen to Dr. O & The Pinker every Sunday from 7-9pm CST on am 560 WIND or catch us on the web at


7 Responses to Nutritional Complications of Bariatric Surgery

  1. One thing that I have observed that is not mentioned here is that although there may be significant weight loss for a time, it is entirely possible for the recipient of this surgery to gain back all weight loss and more.

    I know a man who had this done years ago. When I measured him for a costume I found that he had a 67 inch hip, and overall high measurements. So he ended up being nutritionally compromised AND even larger than when he got the surgery.

    What is the point?

  2. I wish you had been the doctor for my friend’s husband, who died of complications from gastric bypass of some sort. I don’t know which particular procedure he had, but he wasn’t terribly overweight. Yet the doctor convinced him–using the exact argument you do about seeing kids graduate, grand kids, etc.–that he needed the surgery. As a result, he died before his daughter turned 3 and his son (who was on the way) was born. Perhaps he would have tried the proper diet instead! I wish I had known about this WOE then!

  3. I can attest personally to the fact that it is very likely that a post gastric surgery patient will regain the weight plus acquire nutritional deficiencies plus a considerably maladapted metabolism due to the extended period of starvation.

  4. I had RNY 10 years ago and I do suffer from malnutrition to an extent. I went from 311 to 186 in 8 months and 10 years later my weight is… 186. I do get an IV or iron about every other year and do daily b12 shots. I do have a problem now with my skin. My collagen is VERY weak and the slightest side to side motion on my skin will tear the layers making a horrible mark for two weeks. A skin Dr. was clueless as well. I don’t know what to do about it! I am 50 years old and have the skin of an 80 year old. I’m assuming maybe it’s from my protein deficiency. I do two or three very high quality protein drinks a day and my level still registers low. I am pleased with my results except for the low protein, which makes me soooo tired! Do you have any answers?

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