Vitamin B12 Deficiency
What is Vitamin B12 Deficiency?
Vitamin B12 deficiency occurs when your body does not have enough vitamin B12 to function properly. Vitamin B12 is a nutrient your body needs to make red blood cells, support nerve function, and create DNA. Your body cannot make B12 on its own, so you must get it from animal foods or supplements.
When B12 levels drop too low, your body struggles to produce healthy red blood cells. This can lead to a type of anemia called megaloblastic anemia, where red blood cells are larger than normal and cannot carry oxygen efficiently. Over time, low B12 can also damage your nerves and affect your brain function.
This condition is more common than many people realize. It affects up to 15 percent of the general population and is especially common in older adults, vegetarians, and people with digestive disorders. The good news is that B12 deficiency is treatable once identified through blood testing.
Symptoms
- Fatigue and weakness that does not improve with rest
- Pale or yellowish skin tone
- Shortness of breath and dizziness
- Tingling or numbness in hands and feet
- Difficulty walking or balance problems
- Sore or swollen tongue
- Memory problems or difficulty concentrating
- Mood changes including depression or irritability
- Constipation, loss of appetite, or weight loss
- Vision problems in severe cases
Some people with B12 deficiency have no obvious symptoms in the early stages. This is why regular blood testing is important, especially if you have risk factors. Nerve damage from B12 deficiency can become permanent if left untreated for too long.
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Causes and risk factors
Vitamin B12 deficiency happens for several reasons. The most common cause is poor absorption in the digestive system rather than lack of B12 in your diet. Your stomach produces a protein called intrinsic factor that helps absorb B12 in the small intestine. Some people develop antibodies that block intrinsic factor, preventing B12 absorption. This condition is called pernicious anemia and becomes more common with age. Stomach infections with H. pylori bacteria can also interfere with B12 absorption by damaging the stomach lining.
Other risk factors include following a strict vegetarian or vegan diet, since B12 is found mainly in animal products. People who have had stomach or intestinal surgery may struggle to absorb B12. Certain medications like metformin for diabetes and proton pump inhibitors for acid reflux can reduce B12 absorption over time. Older adults over age 50 produce less stomach acid, making it harder to extract B12 from food. Conditions like Crohn disease and celiac disease also increase your risk by damaging the intestines.
How it's diagnosed
Vitamin B12 deficiency is diagnosed through blood tests that measure your B12 levels and related markers. Rite Aid's blood testing panel includes Vitamin B12, Folate, Methylmalonic Acid, Homocysteine, and other biomarkers that help identify B12 deficiency. Your doctor may also test for Intrinsic Factor Blocking Antibody to check for pernicious anemia. A Complete Blood Count can show if you have anemia and whether your red blood cells are larger than normal.
Testing for B12 deficiency is important because symptoms can develop slowly and may not be obvious at first. Methylmalonic Acid and Homocysteine levels often rise when B12 is low, providing additional confirmation. If you have risk factors like a vegetarian diet, digestive disorders, or are over 50, regular screening can catch deficiency early before nerve damage occurs. Get tested through Rite Aid's subscription service to monitor your B12 status twice a year.
Treatment options
- B12 supplements in pill form for mild deficiency or dietary causes
- B12 injections for severe deficiency or absorption problems
- High dose oral B12 supplements that can bypass absorption issues
- Nasal spray or under the tongue B12 for some patients
- Treating underlying conditions like H. pylori infection or celiac disease
- Adjusting medications that interfere with B12 absorption
- Eating more B12 rich foods like meat, fish, eggs, and dairy
- Fortified cereals and nutritional yeast for vegetarians
- Regular blood testing to monitor B12 levels during treatment
- Working with a doctor to determine the right dose and delivery method
Concerned about Vitamin B12 Deficiency? Get tested at Rite Aid.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
Early signs include unusual fatigue, weakness, and pale skin. You might notice tingling in your hands or feet, or have trouble concentrating. Some people experience mood changes or a sore tongue before other symptoms appear. Many people have no obvious symptoms until the deficiency becomes moderate or severe.
Most people feel better within a few weeks of starting treatment. Energy levels and mood often improve first, usually within 2 to 4 weeks. Nerve symptoms like tingling may take 3 to 6 months to resolve completely. In cases of severe or long term deficiency, some nerve damage may be permanent.
Yes, standard B12 blood tests can sometimes miss early deficiency. This is why doctors also check Methylmalonic Acid and Homocysteine, which rise when B12 function is impaired. These markers can detect problems with B12 metabolism even when serum B12 appears normal. Testing multiple biomarkers gives a more accurate picture of your B12 status.
Yes, anyone following a plant based diet should take B12 supplements or eat fortified foods. Vitamin B12 is found naturally only in animal products like meat, fish, eggs, and dairy. Even vegetarians who eat dairy and eggs may not get enough B12. Most doctors recommend that vegetarians and vegans take at least 250 micrograms of B12 daily.
Animal foods provide the most B12, including beef liver, clams, salmon, tuna, and trout. Beef, chicken, eggs, and dairy products like milk and yogurt also contain good amounts. Fortified breakfast cereals and nutritional yeast offer B12 for vegetarians. One serving of clams or beef liver can provide several times your daily B12 needs.
Long term severe B12 deficiency can cause lasting nerve and brain damage. Memory problems, confusion, and difficulty walking may become permanent if deficiency goes untreated for years. Early detection and treatment can reverse most symptoms and prevent permanent damage. This is why regular blood testing is important, especially for people over 50 or those with risk factors.
As you age, your stomach produces less acid, making it harder to extract B12 from food. Many older adults also develop atrophic gastritis, which damages the stomach lining. Some develop antibodies against intrinsic factor, the protein needed to absorb B12. Up to 20 percent of people over 60 have low B12 levels.
Yes, several common medications can lower B12 levels over time. Metformin, used for diabetes, reduces B12 absorption in up to 30 percent of users. Proton pump inhibitors and H2 blockers for acid reflux decrease stomach acid needed to absorb B12. If you take these medications long term, ask your doctor about B12 testing and supplementation.
Injections work faster and are necessary when you cannot absorb B12 through your digestive system. People with pernicious anemia or intestinal problems usually need injections at first. However, high dose oral supplements can work well for many people, even those with absorption issues. Your doctor can help determine which form is best for your situation.
Most healthy adults should test B12 levels at least once every 1 to 2 years. People over 50, vegetarians, or those with digestive disorders should test annually or more often. If you are being treated for B12 deficiency, your doctor may want to retest every 3 to 6 months. Rite Aid's subscription includes testing twice per year to monitor your levels regularly.