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Vitamin B12 deficiency: A silent epidemic with serious consequences

  • Paarl Dietitians
  • Category Advice Column, Baby, Child, Health, Lifestyle, Pregnancy & Baby, Tween & Teen

Vitamin B12 deficiency isn’t a bizarre, mysterious disease. It’s written about in every medical textbook and its causes and effects are well-established in the scientific literature. However, B12 deficiency is far more common than most health care practitioners and the general public realise. Research suggests that 40 percent of people between the ages of 26 and 83 years have vitamin B12 levels in the low normal range – a range at which many individuals experience neurological symptoms.

Symptoms of a vitamin B12 deficiency are easily mistaken for signs of other ailments. If you’re feeling more anxious, tired, or worn out than usual, a B12 deficiency may be to blame. Vitamin B12 deficiency can be sneaky and harmful, so keep reading for some insight.


Vitamin B12 is a water-soluble vitamin and is also the only B vitamin that is almost exclusively found in animal foods. The human body needs vitamin B12 (together with folate) to make red blood cells, DNA and help promote healthy function of nerves. In addition, B12 is one of the vitamins responsible for a well-functioning metabolism and robust energy levels.

Like most vitamins, B12 can’t be made by the body. Instead, it must be gotten from food or supplements. And therein lies the problem: Some people don’t consume enough vitamin B12 to meet their needs, while others can’t absorb enough, no matter how much they take in. The absorption of B12 is also complex and involves several steps – each of which can go wrong. As a result, vitamin B12 deficiency is relatively common.


There are many causes for vitamin B12 deficiency. In general, the following groups are at greatest risk for a deficiency:

Vegetarians and vegans

Because B12 is not generally found in plant-based foods, vegetarians are at risk for B12 deficiencies. This explains why studies consistently demonstrate that up to 50% of long-term vegetarians and 80% of vegans are deficient in B12.

People aged 60 or over

The condition is more likely to occur in older people due to the cutback in stomach acid production that often occurs with ageing, making it harder to absorb this vitamin. It has been estimated to affect about 40% of people over 60 years of age. It’s entirely possible that at least some of the symptoms we attribute to “normal” ageing – such as memory loss, cognitive decline, decreased mobility, etc. – are at least in part caused by a vitamin B12 deficiency.

People who regularly use PPIs or acid suppressing drugs

If you take proton pump inhibitors (PPIs) e.g. omeprazole (antacid or heartburn drugs) you may be at risk for B12 deficiency. These drugs reduce acid production in the stomach and acid is needed to absorb vitamin B12.

Medical conditions

Conditions that interfere with food absorption, such Coeliac or Crohn’s disease, Ulcerative colitis, irritable bowel syndrome (IBS), bacterial overgrowth (intestinal dysbiosis), atrophic gastritis (thinning of stomach lining) or gut inflammation, pernicious anaemia (an autoimmune condition where the body destroys intrinsic factor, a protein necessary for the absorption of B12) can cause B12 trouble.

Certain medications

Use of some commonly prescribed drugs such as metformin (insulin resistance and diabetes), or anti-seizure medications such as phenytoin may cause a B12 deficiency.

Heavy drinkers or alcoholism

Drinking alcohol, even in moderation (more than one alcoholic drink a day), can have profound effects on the way your body absorbs vitamin B-12.

Genetic variations

Common genetic variations may interfere with the absorption of vitamin B12, and subsequently levels of the vitamin in the blood.

Weight loss surgery 

People who have stomach stapling or other forms of weight-loss surgery are also more likely to be low in vitamin B12 because the operation interferes with the body’s ability to extract vitamin B12 from food.


Vitamin B12 deficiency can be slow to develop, causing symptoms to appear gradually and intensify over time. It can also come on relatively quickly.

A vitamin B12 deficiency occurs in four stages.

  • Stage 1 – beginning with declining blood levels of the vitamin
  • Stage 2 – progressing to low B12 levels within the body’s cells
  • Stage 3 – increased blood level of homocysteine and reduced ability to repair and produce DNA
  • Stage 4 – finally, macrocytic anaemia


A vitamin B12 deficiency can cause anaemia (low red blood cell production). Red blood cells carry oxygen all over the body. When the body does not produce enough red blood cells, the amount of available oxygen in the body, decreases as well. B12-related anaemia can cause many other issues, including:

  • Extreme Fatigue: It’s normal to get tired during the day if you didn’t sleep well the night before, just ate a large meal, or completed strenuous exercise. But it isn’t normal to experience an overwhelming fatigue that doesn’t go away with rest.
  • Muscle Weakness: You might experience soreness after a hard workout for a day or two, but if your muscles feel like you just ran a marathon after a simple activity like brushing your hair, you may be anaemic.
  • Heart Palpitations: Feel a flutter in your chest? You could be experiencing heart palpitations due to decreased oxygen circulation.
  • Breathlessness: Breathlessness is normal after activity, but if you find yourself short of breath during rest, it’s an indicator that something’s not right. Just like heart palpitations, anaemia can cause breathlessness due to a lack of oxygen in the blood.
  • Pale Skin: Red blood cells are responsible for the rosy colour in our cheeks. When red blood cell production decreases—as it does in anaemic individuals—the skin becomes pale and colourless.

Pins-and-Needles Sensation

You know the pins-and-needles sensation you often get when your foot falls asleep? This sensation is called peripheral neuropathy and can be linked to nerve damage caused by a B12 deficiency. According to the Foundation for Peripheral Neuropathy, a B12 deficiency damages the sheath that surrounds and protects nerves, resulting in an unpleasant and sometimes painful tingling sensation. Other diseases such as diabetes can also cause a pins-and-needles sensation, so it’s always best to talk to your doctor to rule out other conditions.

Forgetfulness and Confusion

One of the more frightening symptoms of B12 deficiency is severe forgetfulness and confusion. This symptom most frequently occurs in older adults and can be misdiagnosed as dementia. It’s normal to experience what’s called brain fog every now and then, like forgetting where you parked your car or why you came to the grocery store in the first place. But if you are consistently unable to recall an individuals’ name or often find yourself in a certain place with no recollection of how you got there, you may be experiencing extreme B12 deficiency.

Mood Disorders

Many mood disorders, including anxiety and depression, are linked to low levels of B12. B12 helps regulate the production of mood-controlling chemicals such as serotonin. When B12 levels are lowered, production of these chemicals are interrupted, this can result in certain mood disorders. Of course, anxiety and depression can be caused by many other factors, like stress or hormonal imbalance. But if you find yourself suddenly crying for no reason, or if you experience other symptoms of anxiety, you may want to have your B12 levels checked.

Changes in Vision

Low levels of B12 in the body can cause nerve damage, one of the more serious symptoms of B12 deficiency is blurry vision.

You may also experience shadows over your field of vision or sensitivity to light. If your vision problems are caused by an undiagnosed B12 deficiency, you could risk long-term damage to the optic nerve, resulting in permanent vision loss.


A B12 deficiency can cause a breakdown in red blood cell production, which results in a build-up of bilirubin in the blood. If you notice your skin has taken on a yellow appearance, or the whites of your eyes appear yellow, you may have a B12 deficiency.

Smooth Tongue

In individuals with a B12 deficiency, the tongue will appear swollen, smooth, and bright red. You may also experience glossitis, which is the medical term for an extremely sore tongue.


Given the array of symptoms it can cause, the condition can be overlooked or confused with something else. While an experienced clinician may notice the symptoms and be able to detect a vitamin B12 deficiency with a good interview and physical exam, a blood test is needed to confirm the condition.

It’s a good idea to have your B12 level checked if you present with any of the previously mentioned risk factors. Early detection and treatment is important. If left untreated, the deficiency can cause severe neurologic problems and blood diseases.


A vitamin B12 deficiency are typically treated by means of diet – upping the amount of protein in the diet, B12 injections or supplements. For most people, treatment resolves the problem. But, any nerve damage that happened due to the deficiency could be permanent.

A serious vitamin B12 deficiency can be corrected two ways: weekly shots of vitamin B12 or daily high-dose B12 pills. A mild B12 deficiency can be corrected with a standard multivitamin (high in B-vitamins).

Adequate treatment also depends on the underlying mechanism causing the problem. People with pernicious anaemia or inflammatory gut disorders like Crohn’s disease are likely to have impaired absorption for their entire lives, and will likely require B12 injections or high dosage supplementation indefinitely. This may also be true for those with severe B12 deficiency causing neurological symptoms.

What to look for when buying B12 

Vitamin B12 is available in many different forms. Cyanaocobalamin is the most frequently used form of B12 supplementation. But recent evidence suggests that methylcobalamin may be superior – especially for neurological disease. Methylcobalamin may be better absorbed because it bypasses several potential problems in the B12 absorption cycle. On top of that, methylcobalamin provides the body with methyl groups that play a role in various biological processes important to overall health. So, do check which form of B12 your supplement contains.

Important: When a person with a B12 deficiency is being treated with supplements or B12 injections, it is important to have blood levels re-checked to monitor response to treatment.

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  • Jamal Salem Aljifri April 14, 2022 at 2:05 pm

    Clinicians waiting for enlarged red blood cells or macrocytic anemia to be present before testing or treating patients, that’s why vitamin B-12 deficiency is an epidemic.


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