Warning signs of Vitamin B12 deficiency you might be ignoring for years

Vitamin B12 is a vital nutrient responsible for red blood cell formation, nerve health, and the creation of DNA. Even though it is crucial to our body's needs, many are not aware they are suffering from a B12 deficiency, as its development may happen slowly and get mistaken for other diseases. Since our body doesn't produce B12 naturally, it needs to be consumed from foods such as meat, milk, and fortified products, or through supplements.

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One of the oldest and most neglected warning signs of B12 deficiency is constant tiredness. As B12 is crucial for the formation of red blood cells, its deficiency can result in the body not having enough oxygen, leading to chronic fatigue and weakness in muscles. Unlike normal tiredness, which disappears after rest, constant tiredness and muscle weakness due to B12 deficiency do not subside despite rest and can increase progressively.

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Deficiency in B12 impacts nerve function, and one of the earliest signs is paresthesia—a feeling of numbness or tingling in the hands, feet, or even tongue. This is caused by damage to nerves through the lack of myelin, a nerve protective sheath. Most individuals downplay this symptom as temporary or attribute it to staying in a strange position for an extended period. If it is not heeded, this may result in irreversible nerve damage.


Others with low B12 levels describe a sudden, electric shock-type pain that courses through their body, often in their legs or back. This is caused by nerve damage and can become chronic if not treated.

B12 is important in brain function and the synthesis of neurotransmitters, influencing mood control. Deficiency can cause irritability and mood swings, enhanced anxiety and restlessness, depression and lack of interest in daily activities. Such symptoms tend to be confused with normal stress or mental illness. If a person has ongoing mood changes accompanied by other signs of B12 deficiency, one should have their nutrient levels checked.

If you find that you are experiencing forgetfulness, having trouble concentrating, feeling drowsy mentally (brain fog), then it could be that you lack vitamin B12. As B12 is vital to mental function, its lack can cause memory loss and information processing difficulty. Most people attribute this to aging, stress, or workload, not considering the likelihood of a nutritional deficiency.

A B12 deficiency will make the skin pale or pale yellow (jaundice). This is due to the body's inability to produce sufficient red blood cells, resulting in anemia. Therefore, the skin loses its natural healthy sheen, and a few people develop a yellow color in the whites of their eyes from elevated bilirubin.

Because B12 is essential to the formation of red blood cells, its deficiency can result in anemia, which can lead to poor oxygen flow. This can lead to:


Shortness of breath even with the slightest exertion

Frequent dizziness or lightheadedness

Occasional heart palpitations

Individuals tend to attribute these symptoms to lack of fitness or dehydration, but recurring dizziness must not be dismissed.

Loss of appetite and unexplained weight loss can also be an indicator of a B12 deficiency. Because this vitamin aids in sustaining energy levels and metabolism, falling levels can decrease the hunger signal. People can lose weight steadily without any known reason, which tends to go unnoticed until it is severe.

Deficiency in vitamin B12 may lead to inflammation of the tongue (glossitis), which is swollen, red, and sore. Some individuals also get mouth ulcers, causing pain when eating or speaking. This condition is usually misdiagnosed as an allergy or infection, which causes the diagnosis to be delayed.

B12 is also involved in optic nerve health. Deficiency leads to:


Blurry vision

Sensitivity to light

Difficulty focusing on objects

With time, the untreated B12 deficiency can progress to optic neuropathy, and it results in permanent vision impairment. Most people neglect this sign, thinking that it's either eye strain or age.

Individuals with chronic B12 deficiency may experience poor coordination, balance difficulties, and frequent falls. This is caused by nerve damage in movement control. Although older adults tend to blame this on aging, it might be a precursor to a nutritional deficit that must be attended to urgently.

Vitamin B12 deficiency lowers the blood pressure, resulting in frequent spells of fainting, feeling abnormally cold and experiencing weakness in muscles. These symptoms are usually waved off as a general fatigue or dehydration, but they could be due to an underlying nutritional deficiency.

Most patients of B12 deficiency complain of digestive issues like:

Chronic constipationConstant bloating and gasDiarrhea in a few cases
These symptoms tend to be confused with irritable bowel syndrome (IBS), which causes a delay in appropriate diagnosis and treatment.

Some groups are more susceptible to developing B12 deficiency, including:
Vegetarians and vegans (since B12 primarily exists in animal foods)Older adults (because they absorb less poorly)Individuals with gastrointestinal illnesses (such as Crohn's disease, celiac disease)Individuals who have had weight-loss surgeryIndividuals taking long-term medications for acid reflux

The recommended daily intake of Vitamin B12 varies by age and condition, with adults generally needing 2.4 mcg per day, while pregnant and breastfeeding women require 2.6–2.8 mcg. Infants, children, and teenagers have lower requirements, ranging from 0.4 mcg to 1.8 mcg depending on age. However, some individuals may need higher amounts, such as vegetarians, vegans, older adults, and those with digestive disorders like Crohn’s disease or celiac disease, which can impair B12 absorption.

Vitamin B12 deficiency is common in vegans and vegetarians since B12 is primarily found in animal-based foods. Older adults are at risk due to reduced stomach acid needed for B12 absorption. People with digestive disorders like Crohn’s disease, celiac disease, or those who’ve had gastric bypass surgery may struggle to absorb B12. Pregnant and breastfeeding women, especially those on plant-based diets, need higher B12 intake. Heavy drinkers and individuals on long-term antacid or metformin use may also develop deficiencies. Symptoms include fatigue, weakness, memory issues, and tingling sensations. Regular supplementation or fortified foods help prevent deficiency.(Images: Canva)

Vitamin B12 is primarily found in animal-based foods, making it essential for those who consume a non-vegetarian diet. Rich sources include meat (lamb, pork), poultry (chicken, turkey), fish (salmon, tuna, sardines), and shellfish (clams, oysters, crab). Dairy products like milk, cheese, and yogurt, along with eggs, also provide B12. For vegetarians and vegans, fortified foods such as plant-based milk, cereals, and nutritional yeast can help meet their B12 needs. Additionally, B12 supplements or injections may be necessary for those with dietary restrictions or absorption issues.

Early signs of vitamin B12 deficiency can be subtle but worsen over time. Persistent fatigue and weakness occur as B12 is crucial for red blood cell production. Tingling or numbness in hands and feet results from nerve damage. Pale or yellowish skin (jaundice) indicates reduced red blood cells. Dizziness, balance issues, or difficulty walking may develop due to neurological impairment. Mouth ulcers, a swollen tongue, or a burning sensation in the mouth are common oral symptoms. Memory problems, difficulty concentrating ("brain fog"), and mood changes like irritability or depression can also appear. Timely diagnosis and supplementation are essential to prevent complications.