Vitamins and Supplements: Signs You're Low on Vitamin B12

Reviewed on 4/13/2022

Numbness

B12 deficiency can cause numbness and tingling.

Do your hands, feet, or legs feel like they're on "pins and needles"? Shortage of B12 can damage the protective sheath that covers your nerves. Diseases like celiac, Crohn's, or other gut illnesses may make it harder for your body to absorb the vitamin. So can taking some heartburn drugs.

You're Colder Than Usual

B12 deficiency means fewer red blood cells, so you might feel cold.

Without enough B12, you might not have enough healthy red blood cells to move oxygen around your body (anemia). That can leave you shivering and cold, especially in your hands and feet.

Brain Fog

Lack of sufficient B12 may lead to confusion and memory problems.

A lack of B12 may lead to depression, confusion, memory problems, and dementia. It also can affect your balance. B12 supplements are usually safe. For adults, doctors recommend 2.4 micrograms a day. If you take more than what you need, your body passes the rest out through your pee. Still, high doses could have some side effects, like dizziness, headache, anxiety, nausea, and vomiting.

Weakness

Weakness, tiredness, and lightheadedness may mean you don't have enough B12.

Your muscles may lack strength. You also might feel tired or lightheaded. Your doctor can check how much B12 is in your body, but not all of it may be useable. So it's important to pay attention to any symptoms -- which can grow slowly or pop up more quickly -- and to alert your doctor.

Smooth Tongue

Inadequate B12 levels may lead to a smooth, sore tongue.

Your doctor might call it atrophic glossitis. Tiny bumps on your tongue called papillae start to waste away. That makes it look and feel kind of smooth and glossy. Infections, medication, and other conditions can cause it, too. But if not enough B12 or other nutrients is to blame, your tongue also may be sore.

Herbivores Beware

Vitamin B12 is found exclusively in animal products so vegans need to eat fortified foods.

B12 deficiency is rare because your body can store several years' supply of the stuff. But plants don't have any B12. So vegans and vegetarians who don't eat any animal products should add some processed grains like fortified breads, crackers, and cereals.

Heart Palpitations

Heart palpitations are one possible symptom of vitamin B12 deficiency.

This is when your heart suddenly races or skips a beat. You might feel it in your throat or neck. You can get more vitamin B12 from chicken, eggs, and fish. But one of best sources by far is something that may not be a regular on your menu: beef liver.

Reason for Shortage: Age

People absorb less B12 as they age.

As you get older, your body may not absorb B12 as easily. If you don't treat it, low levels of B12 could lead to anemia, nerve damage, moodiness, and other serious problems. So watch for any symptoms, and get a blood test if your doctor recommends it.

Reason for Shortage: Weight Surgery

Gastric bypass may result in low levels of B12.

One of the more common weight loss operations is called "gastric bypass." After the surgery, food bypasses parts of your stomach and small intestine. That's usually where B12 breaks down into usable form. Your doctor likely will monitor your B12 levels and suggest supplements or shots if you need them.

Mouth Sores

Lack of B12 can cause mouth sores.

You may get these ulcers on your gums or tongue. They could be a sign of low B12, anemia, or another condition. The sores usually clear up on their own, but it helps to avoid ingredients that might be irritating or painful, like vinegar, citrus, and hot spices like chili powder. Some over-the-counter medicines could soothe your pain.

Reason for Shortage: Medications

Certain medications interfere with B12 absorption or activity.

Some drugs drop your B12 levels or make it harder for your body to use the vitamin. They include:

  • Chloramphenicol (Chloromycetin), an antibiotic used to treat infection
  • Proton pump inhibitors like lansoprazole (Prevacid) and omeprazole (Prilosec)
  • Peptic ulcer meds like cimetidine (Tagamet) and famotidine (Pepcid)
  • Metformin for diabetes.

Tell your doctor and pharmacist about all drugs and supplements you take.

Digestive Woes

Low B12 can lead to digestive troubles.

You might lose your appetite, drop too much weight, or have trouble pooping (constipation). If your B12 levels are low, your doctor will often inject it into a muscle to be sure your body absorbs it. Sometimes, high doses of pills work just as well. But remember that symptoms of B12 deficiency can be similar to signs of many other illnesses.

Caution for Pregnant Vegetarians

B12 is extra important for pregnant and nursing mothers and their babies.

Talk to your doctor about B12 supplements, both during pregnancy and breastfeeding. Infants who don't get enough could have serious and permanent damage to their nerves or brain cells. Your baby might need supplements, too.

Vitamins and Supplements: Signs You're Low on Vitamin B12

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