As usual, we are discussing relatively benign forms of functional anaemia because what we are describing doesn’t require a specialist, namely a haematologist, to treat these conditions. A diagnosis of anaemia implies a lack of haemoglobin, which implies a deficiency of red blood cells that are necessary to transport haemoglobin, which results in less oxygen supply to the tissues. You may not be surprised to learn the typical symptoms associated with anaemia: pale skin, fatigue and rapid shortness of breath even with only a moderate level of effort.
Essentially, the synthesis of haemoglobin requires three basic components: iron (4 atoms for each molecule of haemoglobin), folic acid (or vitamin B9) and vitamin B12 (or cobalamin). Just missing one of the so-called “anti-anaemic” nutrients and the production of haemoglobin by the bone marrow could be diminished or blocked. We always thinks first of iron deficiency and often not of the B vitamins even though they are also essential.
Vitamin B12 has a remarkable feature: you can only find it in foods of animal origin and therefore vegetarians will most likely be deficient and of course vegans even more so. However it is not sufficient to just consume products rich in vitamin B12 - meats, fish, and shellfish - as with all nutrients they need to be properly absorbed! This implies a good digestive system. I have examined with great detail the complex physiology of vitamin B12 absorption in an article in English posted on my website: www.gmouton.com: click on “Articles” then the heading “Nutrition and Function” and you will access the article in question (“Elevated Vitamin B12 Blood Levels"), which is fully referenced.
The title of the article may surprise you but it refers to an interesting phenomenon involving patients suffering from Small Intestinal Bacterial Overgrowth (or SIBO). This is the invasion of the small intestine by bacteria that are normally confined to the large intestine and the colon and which have the ability to produce vitamin B12. Please note that all of these remarks are also true for vitamin B9 (folic acid). These differing physiological results derive from the fact that the end part of the small intestine is precisely where vitamin B12 and B9 are absorbed. We find, therefore, in the majority of subjects with a SIBO, abnormally high blood levels of vitamin B12 and / or vitamin B9.
Any person not taking B-vitamin supplements who has an excess of vitamin B12 and / or B9 automatically implies this form of intestinal dysbiosis. It is in fact a common cause of what is labelled Irritable Bowel Syndrome (IBS), although it is of course not the only possible explanation. Please note that the long term use of proton pump inhibitors (omeprazole, lansoprazole, pantoprazole) promotes this disease through the suppression of gastric acid and the consequent increase in pH of the small intestine that results. A favourable environment for bacterial overgrowth is therefore created, perfectly similar to what happens in the colon. Gas, bloating, abdominal cramps and loose stools reflect these digestive disorders and an increased blood level of vitamin B12 is biological evidence.
Measuring vitamin B12 levels therefore offers important data concerning whether a person should be considered as a perfect omnivore, or as a carnivore (B12↑), or as a vegetarian (B12↓). Any distortion of these results compared to what might be expected implies a digestive malabsorption (level of B12 lower than expected) or a bacterial overgrowth of the small intestine (level of B12 higher than expected). There is, to my knowledge, no other biological parameter, which by its mere interpretation implies such an ability to provide key diagnostic insight.