Vitamin B12 Deficiency Symptoms That Most People Ignore

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. Here are some signs that you need to up your B12 intake.

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What is B12? Vitamin B12 is one of the vitamins responsible for a well-functioning metabolism and robust energy levels. In addition, B12 helps promote healthy function of red blood cells and nerve tissue. It’s found naturally in high-protein foods such as meat, fish, eggs, and milk.

Who is at risk for B12 deficiency?

Because B12 is not generally found in plant-based foods, vegetarians are at risk for B12 deficiencies. Older adults are also at risk, because the body doesn’t readily absorb B12 as we age. If you take proton pump inhibitors (PPIs) for chronic heartburn or have been diagnosed with a gastrointestinal condition like Crohn’s disease, you may also be at risk for B12 deficiency.

B12 Deficiency Treatments

Most symptoms can be treated simply by increasing the number of B12-rich foods in your diet. If you suffer from a mild deficiency, upping your protein intake might be enough to get your energy back. If your B12 deficiency is more severe, you may need B12 injections or supplements to get your health back on track. Not sure if you’re getting enough B12? Check to see if any of these b12 deficiency symptoms apply to you.

1. Anemia

A B12 deficiency can cause anemia (low red blood cell production). Red blood cells carry oxygen all over the body. When the body doesn’t produce enough red blood cells, the available oxygen decreases as well. B12-related anemia 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 anemic.

Heart Palpitations

Feel a flutter in your chest? You could be experiencing heart palpitations due to decreased oxygen circulation.


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, anemia can cause breathlessness due to a lack of oxygen in the blood.

Pale Skin

Red blood cells are responsible for the rosy color in our cheeks. When red blood cell production decreases—as it does in anemic individuals—the skin becomes pale and colorless.

2. 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 make an appointment with your doctor to rule out other conditions.

3. 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. That’s what happened to Ilsa Katz, the subject of a 2011 New York Times article about vitamin B12 deficiency. Ms. Katz’s daughter noticed her mother’s increasing inability to remember faces and events. She became easily confused and often couldn’t remember where she was going or how she got there. The preliminary diagnosis was Alzheimer’s disease, but routine blood work showed low levels of B12. With a few weeks of B12 injections, Ms. Katz’s condition vastly improved. 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 your boss’ name or often find yourself in a certain place with no recollection of how you got there, you may be experiencing extreme B12 deficiency.

4. Mood Disorders

Many mood disorders, including anxiety and depression, are linked to low levels of B12. As Wellness Mama explains, B12 helps regulate the production of mood-controlling chemicals such as serotonin. When B12 levels are lowered, production of these chemicals are interrupted, which 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.

5. Changes in Vision

If you notice changes in your vision, you might assume it’s time to visit the optometrist. However, a B12 deficiency could be to blame. Because 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.

6. Jaundice

Most of us have only heard of jaundice in reference to newborn babies, who are occasionally born with this condition, in which skin and eyes may take on a yellow tone. Jaundice occurs when bilirubin builds up in the bloodstream. Normally, the liver filters bilirubin out of the body along with old red blood cells. A B12 deficiency can cause a breakdown in red blood cell production, which results in a buildup of bilirubin. If you notice your skin has taken on a sallow appearance, or the whites of your eyes appear yellow, you may have a B12 deficiency.

7. Smooth Tongue

When was the last time you took a good look at your tongue? If you haven’t checked out your mouth lately, it might be time to take a peek. According to Stanford University, the tongue should generally be a pink–red color, have a rough surface (where your taste buds are located), and fit comfortably against your front teeth. If you notice that food just doesn’t taste as flavorful, check your tongue. In individuals with a B12 deficiency, the tongue will actually appear swollen, smooth, and bright red. You may also experience glossitis, which is the medical term for an extremely sore tongue.

Always speak with your doctor.

A B12 deficiency is hard to diagnose because symptoms of low B12 levels are also symptoms of many other conditions and diseases. Although it might be tempting, don’t try to diagnose or treat your symptoms yourself. Speak with your doctor before beginning any treatment—even a vitamin supplement. A simple blood test can confirm if you have a B12 deficiency, and your doctor will recommend the appropriate treatment plan.