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5 Signs You're Not Getting Enough Vitamin B12, Doctors Say

Experts reveal what to look for if you're worried you're deficient in the vital nutrient.

Maintaining a balanced diet is crucial to your health, and not just for keeping cardiovascular disease and weight gain at bay. It also helps ensure you're getting all of the essential vitamins and minerals your body needs to function correctly. One of these essential vitamins is vitamin B—especially B12, which we often get from eating meat, fish, seafood, eggs, and dairy. However, it's possible to miss the mark with your recommended intake.

"Vitamin B12 deficiency is relatively common, especially among older adults, vegetarians, and vegans," says Samantha Turner, MPH, RDN, a registered dietitian and owner of Forks and Grace. "[Vitamin B12] plays an important role in supporting nerve and brain health and energy metabolism, and is crucial for nerve development, DNA synthesis, and red blood cell formation."

While a visit to the doctor can expose a deficiency, there are still other red flags to look out for. Read on for the signs you're not getting enough vitamin B12, according to doctors and nutritionists.

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Woman experiencing fatigue at home

Feeling sleepy, rundown, or lacking in energy overall may be a sign of any number of health problems. It can also point to a lack of the vital nutrient in your body.

"Vitamin B12 is essential to make healthy red blood cells," says Leann Poston, MD, a licensed physician and health advisor for Invigor Medical. "Low B12 levels can decrease red blood cell production and make it difficult for them to deliver oxygen to body cells, which can cause fatigue."

Fertility Issues

Woman getting an ultrasound

One dietary expert says lacking in vitamin B12 could become an issue if you're planning on conceiving.

"Vitamin B12 deficiency has been linked to infertility as vitamin B12 improves the number of healthy eggs and embryo quality," Qianzhi Jiang, PhD, RDN, a family dietitian and owner of The Nutrition Changer, tells Best Life.

She adds that a low level of vitamin B12 is also associated with increased homocysteine, an amino acid that can increase the risks of many diseases when in excess). "Elevated homocysteine levels can damage the lining of the uterus, causing infertility," Jiang says.

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Numbness, Tingling, and Neurological Effects

man massaging his hand and fingers

If you notice pins and needles in your extremities, it's possible your body is running low on vitamin B12.

"Vitamin B12 deficiencies can cause changes in how your nerves send messages throughout your body," says Poston. "As the rate at which nerve impulses decreases, your body interprets this with numbness and tingling."

And those aren't the only effects you might feel. "People with vitamin B12 deficiency can experience irritability, abnormal gait, an impaired sense of smell, and absences of neurologic reflexes such as the knee-jerk reaction," says Jiang.

She adds that when a severe deficiency is at play, psychiatric symptoms that resemble the symptoms of dementia can also occur.

Mouth Soreness

Young woman looking inside her mouth in a mirror

Noticing some tenderness in your mouth that's not related to a burn or toothache? According to Poston, it could be a sign you're lacking in the essential nutrient.

"Vitamin B12 deficiency can cause glossitis," she explains. "This appears as a smooth appearance of the tongue that can be painful."

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Pale Skin Color

insecure man examining his skin in the mirror

According to Poston, a vitamin B12 deficiency can cause misshapen red blood cells. "These cells get caught in the spleen, decreasing the number of red blood cells circulating. This condition, called anemia, can cause pale skin color," she explains.

However, it's also possible to notice signs of this condition that are more than skin deep.

"Some people may see no or very mild symptoms caused by pernicious anemia for years while others may experience fatigue, muscle weakness, or palpitations (which is a feeling that your heart is pounding or skipping a beat)," says Jiang. "However, pernicious anemia may not be seen in cases of mild vitamin B12 deficiency."

Best Life offers the most up-to-date information from top experts, new research, and health agencies, but our content is not meant to be a substitute for professional guidance. When it comes to the medication you're taking or any other health questions you have, always consult your healthcare provider directly.

Zachary Mack
Zach is a freelance writer specializing in beer, wine, food, spirits, and travel. He is based in Manhattan. Read more
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