High Folate, Low Vitamin B12, Anemia from Bacterial Overgrowth

AriannaF82 Asked :

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I recently went for some tests for anemia and now my doctor thinks that I have an excess of bacteria in my small bowel intestine. He also mentioned a condition known as blind loop syndrome. I have been anemic since my teens and now that I am 26 years old and on my own health insurance, I decided to get it attended to.

I was always under the impression that it was low blood iron levels that cause anemia but after further testing, my doctor tells me that it is a vitamin B12 issue. He also told me that my folate levels are slightly higher than normal. I am quite confused how this condition could cause a high folate level. I have had IBS from my teens and I hope to fall pregnant within a year or so and would like to get any health problems sorted out as soon as possible.

Could there be other causes of the high folate and low vitamin B12?


This question was posted under the Blood Iron Levels – High, Abnormal, Low article.

Any response by the Health Hype team does not constitute a medical consultation and the advice should be viewed purely as a guide. Always consult with your doctor before making any changes to your current treatment program. The information provided in this article is not an authoritative resource on the subject matter and solely intends to guide the reader based on the questions asked and information provided.


Dr. Chris Answered :

Your doctor obviously came to this differential diagnosis after seeing the results of your tests in conjunction with your case history. Small bowel bacterial overgrowth may explain many of your symptoms – those of anemia and what you may have thought was IBS. In this condition, bacteria that is normally found in the colon (coliform bacteria) start contaminating the small intestine. It is most often due to a disorder that impairs the movement of food through this area. The food stays longer than it should in this area and causes a host of symptoms like diarrhea, abdominal pain and so on which may be taken for IBS. However, you may have IBS which may be separate from the bacterial overgrowth or your symptoms could be due to inflammatory bowel disease which is also a cause of small bowel bacterial overgrowth.

Absorption of nutrients from the small intestine is affected and the bacteria here utilize vitamin B12 thereby leading to a deficiency. At the same time these bacteria produce folic acid which could cause a moderately high folate level.There are different types of anemia and you should speak to your doctor and ask him if your anemia is due to an iron deficiency or vitamin B12 deficiency. There could also be other causes for your anemia. Small bowel bacteria overgrowth may also affect the absorption of other nutrients, including iron.

There are a number of causes of small bowel bacteria overgrowth and your doctor will try to confirm this diagnosis and ascertain a cause of this condition. If it has existed for all of these years, it should have been identified at this point. Your doctor may have suspected small bowel bacterial overgrowth and just mentioned blind loop syndrome as one of the possible causes. It is possible that these symptoms are due to some other condition which is also slows the movement of foods and results in small bowel bacterial overgrowth.

Speak to your doctor about your concerns. Some of the causes of small bowel bacterial overgrowth like diabetes, or hypothyroidism could affect a future pregnancy. First allow you doctor to confirm or exclude the differential diagnosis before considering other causes of a high folate and low vitamin B12 level. You can refer to this article on Small Intestine Bacterial Overgrowth Symptoms and Treatment for more information.

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  • Abby

    I have an ileomostomy and my folate is high and my iron is very low. I also have slow motility and am very underweight. Could this be due from bacteria in my small intestines, and if so what can I do? Thanks Abby

  • Dr. Chris

    Hi Abby

    It could possibly be a bacterial overgrowth, however, the surgical procedure you have undergone can also affect nutrient absorption. Your doctor and the surgeon who conducted this procedure will be better suited to advise you further. You may need to work with a dietitian as well for a suitable eating plan.

  • Chloe

    Not sure if this helps or if anyone is interested but I recently heard about a new oral prescription alternative to the injections called Eligen B12. I read that it works even if you don’t have intrinsic factor (so even if you don’t have normal gut absorption, which would mean no more shots. Apparently it came out a month or two ago. Has anyone tried it??