Why Vitamin B12 Deficiency Can Be a Serious Issue

Vitamin B12, also known as cobalamin, is an essential nutrient your body needs to function properly. 

It plays a crucial role in red blood cell formation, neurological function, and DNA synthesis. 

Despite its importance, vitamin B12 deficiency is surprisingly common — and it can lead to serious health complications if left untreated.

What Causes Vitamin B12 Deficiency?

There are several reasons why someone might become deficient in B12:

Dietary deficiencies – Those who follow a vegan or vegetarian diet are at higher risk, as B12 is found almost exclusively in animal products such as meat, fish, eggs, and dairy.

Absorption problems – Conditions such as pernicious anaemia, coeliac disease, Crohn’s disease, or certain gastrointestinal surgeries can interfere with B12 absorption.

Ageing – As we age, our ability to absorb B12 from food naturally decreases.

Medication use – Long-term use of certain medications, such as proton pump inhibitors (PPIs), metformin, or antacids, can impact absorption.

Symptoms of Vitamin B12 Deficiency

Vitamin B12 deficiency can be sneaky. Early symptoms are often mild and easy to dismiss. However, if the deficiency progresses, symptoms can become severe and even irreversible.

Common symptoms include:

Fatigue and weakness

Pale or jaundiced skin

Pins and needles (paraesthesia)

Mouth ulcers and glossitis (a swollen, inflamed tongue)

Shortness of breath and dizziness

Blurred vision

Mood changes, irritability, or depression

Memory loss or cognitive difficulties

Unsteady movements and balance issues

Left untreated, vitamin B12 deficiency can lead to permanent nerve damage, neurological problems, and megaloblastic anaemia, where red blood cells become too large and can't function properly.

Why It’s Especially Important in Certain Populations

Certain groups are more vulnerable to B12 deficiency and should monitor their levels closely:

Vegans and vegetarians: Without fortified foods or supplements, plant-based diets may lack sufficient B12.

Older adults: Absorption issues become more prevalent with age.

People with gastrointestinal disorders: Diseases like Crohn’s or those who have undergone bariatric surgery can affect B12 uptake.

Pregnant women: Deficiency can impact the baby’s development and increase the risk of neural tube defects.

How to Prevent and Treat B12 Deficiency

Dietary sources of B12 include beef, liver, fish, dairy, and eggs. Fortified cereals and plant milks can also help.

For those at risk, B12 supplements are a safe and effective way to prevent deficiency. These come in tablet form, sublingual (under the tongue), or via injections in more severe cases. The NHS may prescribe B12 injections if deficiency is due to absorption issues or pernicious anaemia.

When to See a Doctor

If you experience ongoing fatigue, memory issues, mood changes, or any of the symptoms listed above, speak to your GP. A simple blood test can diagnose a B12 deficiency, and early detection is key to preventing long-term damage.

In Summary

Vitamin B12 deficiency is more common than many realise and can have significant, even permanent, effects on your health if not addressed. With the right awareness, dietary adjustments, and medical support, it is entirely manageable. Whether you follow a plant-based diet or simply want to protect your wellbeing, understanding the role of B12 could make a huge difference to your long-term health.