8 Silent Signs You’re Not Eating Enough Vitamin B12

Vitamin B12 is a nutrient involved in head-to-toe health, from creating blood cells to maintaining our nervous system and supporting psychological processes. Although we only need a tiny amount through our diet—2.4 micrograms daily, per the National Institutes of Health (NIH)—many Americans aren’t getting enough vitamin B12. True deficiency is relatively uncommon in the US, but up to 40% of us have low or marginal B12 status, says Julia Zumpano, RD, LD, a registered dietitian with the Cleveland Clinic Center for Human Nutrition. 

Here’s the problem: Diagnosing B12 deficiency can be relatively difficult because symptoms often affect people differently, might be subtle, and can mimic other conditions. “There is a chance people can have low levels without symptoms,” Zumpano adds. Some people with inadequate vitamin B12 intake may appear healthy for years—but over time, this undetected deficiency can lead to stroke, dementia, poor bone health, and other problems that affect the brain and nervous system, according to 2024 research published in Dietetics. 

That’s why if any of these signs of low vitamin B12 levels apply to you, talk to your doctor about getting tested for a deficiency. You may need to add more vitamin B12-rich foods to your diet or address an underlying cause. 

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Your hands or feet feel numb and tingling

Peripheral neuropathy is the most common symptom of vitamin B12 deficiency, according to 2022 research published in Cureus. It typically shows up as pins and needles, tingling, numbness, loss of sensation, decreased motor activity, or even pain, generally in your hands or feet. 

This occurs because vitamin B12 helps make myelin, the protective covering for nerves—and without it, your nerves get exposed to damage. “When nerves start shrinking, you start going from normal sensations to pins and needles,” says Sonya Angelone, MS, RDN, CLT, a registered dietician nutritionist and national spokesperson for the Academy of Nutrition and Dietetics. 

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You’re exhausted

Feeling overly tired, weak, or short of breath? Your blood cells could be the culprit. Since vitamin B12 plays an important role with blood cells, one of the vitamin B12 deficiency symptoms you could experience is megaloblastic anemia—which causes fatigue, Zumpano says. 

The body starts producing large, immature red blood cells that can’t carry oxygen throughout the body. That lack of oxygen makes you feel run down. But before you make an assumption, rule out these 13 medical reasons you could be fatigued.

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Your skin is pale

Zumpano says that when your skin starts losing its healthy glow, low red blood cell count could be to blame. Vitamin B12 plays a vital role in the development of healthy red blood cells. If you aren’t making enough, “you’re getting less efficient, large cells that aren’t doing the job of carrying oxygen and oxygenating the blood, so that can lead to paleness,” Angelone explains.

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You have oral health issues

Glossitis—inflammation of your tongue—is a potential early sign of low vitamin B12 levels. It occurs due to B12’s impact on cell reproduction, specifically impacting the tongue’s epithelial cells (the cells that cover the skin, body cavities, and blood vessels), Zumpano says. People with low vitamin B12 may also experience mouth sores. It’s unknown why this occurs, but “One theory is that it is related to B12’s impact on cell reproduction,” according to Zumpano. 

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You have difficulty walking

Problems with walking and balance are potential signs of more advanced B12 deficiency. This is due to peripheral nerve damage causing numbness in the legs and the feet, says Zumpano. Untreated, “It can lead to more serious neuropathy or paralysis.” Research published in Cureus in 2022 says that vitamin B12 deficiency is an often overlooked cause of coordination and gait (walking pattern) problems in older people—and that vitamin B12 therapy effectively reduces the risk of falls. 

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You have heart palpitations 

Vitamin B12 is essential for forming red blood cells. So, if you don’t have enough B12, not enough red blood cells are being produced. “The heart beats faster to make up for the low red blood cell count,” Zumpano explains. “This is how the body ensures it’s getting enough oxygen,” and might feel like a racing, fluttering, or pounding heart.

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You’re depressed or irritable

Reduced oxygen to the brain, due to a decrease in red blood cells, can trigger feelings of depression and irritability, Zumpano says. In fact, a 2023 study published in the British Journal of Nutrition shows that adults with low vitamin B12 status had a 51% increased likelihood of developing depressive symptoms. Other research published in Cureus found that a vitamin B12 deficiency can worsen existing symptoms for people with depressive disorders—and that once the deficiency is corrected, the effect of mental health treatments like anti-depressant medications improves. 

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You’re extra forgetful

Since vitamin B12 works closely with metabolic processes in the brain, a deficiency can lead to memory loss and even dementia symptoms, especially in the elderly. Research from 2020 published in Cureus found a clear association between low vitamin B12 levels and progressive cognitive decline—particularly concerning memory and focus.

But Angelone says, “If your cognitive decline is related to diet and B12 deficiency, then that’s easily correctable.” The research agrees, stating that treating B12 deficiency early can help prevent irreversible cognitive decline. 

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What to do if you think you have a vitamin B12 deficiency

Supplementing B12 affects how other B vitamins work, so it’s important to know what’s causing the deficiency instead of guessing and treating it on your own. “Most people don’t get into physiology [when they] take supplements. They just take things because their friend takes it or they heard something about it,” says Angelone. “It’s important to understand what you take and why you take it.” 

If you suspect you have low levels of vitamin B12, ask your doctor for a blood test to confirm vitamin B12 deficiency is causing your symptoms. The fix may be as simple as making some dietary tweaks—or you may be experiencing another underlying cause of vitamin B12 deficiency, such as absorption issues, which you can work with your doctor to correct. 

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