When someone is constantly fatigued and pale, we tend to think iron deficiency which is a microcytic anemia (too small red blood cells). However, what is more common and often underscreened for, is Macrocytic anaemia, (too large red blood cells) which may be caused by a B deficiency predominantly B12 but also folate, B6 and choline. B12 is only found in products like eggs, crickets, meat, shellfish, and dairy.
Why do we need B12
- Forms Red Blood Cells
- Aids in folate and iron absorption
- Produces Adrenal hormones
- Metabolises fats, proteins and carbohydrates
- Essential for myelin sheath production, optimizing nerve growth and function
- Essential for circulation and oxygenation of blood
- Supports nervous system Some of the earliest signs of a deficiency include weakness, fatigue, pins and needles, dizziness, impaired thinking, and confusion.
Who or What may suffer or cause B12 deficiency
- Anyone with an autoimmune disease like Crohn’s or celiac, which may prevent your body from being able to absorb B12
- Those who’ve had gastric bypass surgery and therefore have altered digestive systems, which may be a factor.
- Older adults, because as you grow older, your ability to produce intrinsic factor decreases. As you age, the stomach produces less acid, and stomach acid is key for B12 absorption. About one in 31 adults over 50 are deficient due to reduced stomach acid levels. Intrinsic factor is a protein made by stomach cells that’s necessary for B12 absorption. H. pylori (Helicobacter pylori) bacteria can also destroy them, preventing B12 absorption.
- People who take Metformin, Antacids and H2 receptor blocker drugs may have reduced B12 absorption
- Anyone taking a proton-pump inhibitor like Prevacid or Nexium or H2 blocker such as Pepcid or Zantac. Prescription heartburn drugs may suppress the production of stomach acid needed to absorb vitamin B12. A 2013 study found that taking medications called proton pump inhibitors (like Prilosec and Nexium) for more than two years was linked to a 65% higher risk of vitamin B12 deficiency.
- Women who have been on oestrogen birth control/oral contraceptives may too have issues absorbing vitamin B12 and other nutrients.
B12 deficiency may be mistaken for dementia
Symptoms of a deficiency often mimic those of dementia, such as memory loss, disorientation, and difficulty thinking and reasoning. It can be hard distinguishing deficiency from dementia, especially since older folks are at risk for both. And the two conditions often overlap; 75% to 90% of B12 deficient people also have neurological complications such as dementia.
Poor Microbiome or Gut function
Digestive problems can make absorbing the nutrient more difficult. Gut issues, such as colitis, IBD, IBS and SIBO will cause absorption issues.
Gastric bypass surgery, effects the absorption of B12 particularly because if its effect on Intrinsic Factor.
Diagnosing B12 deficiency
A blood test which examines haematology, B12, liver enzymes, folate, homocysteine, iron studies is a good starting point. Further studies may include intrinsic factor antibodies, gastric parietal cell and Methylmalonic acid blood or urine samples. Gene testing is another consideration.
More information on B12 may be found at
Maxine Haigh-White is a clinical nutritionist.