What is vitamin B12?
Vitamin B12, also known as cobalamin, is a water-soluble vitamin that is essential for many critical processes in the body. It helps keep the body’s nerve and blood cells healthy and helps make DNA. Vitamin B12 also helps prevent a type of anemia called megaloblastic anemia that makes people tired and weak.
The recommended daily amount of vitamin B12 for adults is 2.4 micrograms. You can get this vitamin from foods such as meat, fish, poultry, eggs, milk products, and fortified cereals. Most people get enough B12 from their diet, but some have trouble absorbing the vitamin efficiently. As people get older, their bodies are less able to absorb vitamin B12 from foods.
What causes vitamin B12 deficiency?
There are a few reasons why someone might become deficient in vitamin B12:
– Inadequate intake: A strict vegan or vegetarian diet can increase the risk of B12 deficiency, since this vitamin is found mostly in animal foods. The exception is nutritional yeast, which is fortified with vitamin B12.
– Malabsorption: Certain medical conditions, like celiac disease and Crohn’s disease, can prevent the body from properly absorbing vitamin B12 from foods.
– Pernicious anemia: An autoimmune disorder that prevents the body from properly absorbing vitamin B12 from foods. It is the most common cause of vitamin B12 deficiency.
– Other causes: Long-term use of acid-reducing medications, intestinal surgeries like gastric bypass, heavy alcohol use, and bacterial growth in the small intestine can also contribute to low B12 levels.
What are the symptoms of vitamin B12 deficiency?
Mild to moderate vitamin B12 deficiency may have no signs or symptoms for a long time. Symptoms tend to develop slowly and worsen over time as the deficiency gets more severe. Potential symptoms include:
– Fatigue and weakness
– Lightheadedness or dizziness
– Rapid heartbeat or shortness of breath with exertion
– Pale skin
– Sore tongue or bleeding gums
– Constipation, diarrhea, loss of appetite, or gas
– Nerve problems like numbness or tingling in the hands and feet
– Difficulty walking or moving
– Vision loss
– Depression, memory loss, or behavioral changes
– Dementia
Anemia can also develop, leading to symptoms like excessive fatigue, shortness of breath, and pale skin. Children with B12 deficiency may experience delayed development and failure to thrive.
What happens if vitamin B12 deficiency goes untreated?
Left untreated, vitamin B12 deficiency can potentially lead to serious and irreversible damage, especially to the brain and nervous system. Potential complications include:
Nerve damage
Lack of vitamin B12 can break down the protective myelin sheath that covers nerves. This can result in a condition called subacute combined degeneration that affects the spinal cord. Symptoms may include weakness, numbness, walking difficulties, loss of reflexes, and spastic muscles. This nerve damage can become disabling if left untreated.
Irreversible dementia
Untreated B12 deficiency can potentially lead to irreversible cognitive decline and dementia. Studies show that many patients exhibiting signs of Alzheimer’s disease actually have underlying B12 deficiency. Supplementing with B12 may stop or reverse dementia if caught early enough.
Neuropsychiatric problems
Low B12 levels have been linked to neuropsychiatric disorders like depression, bipolar disorder, and schizophrenia. Studies show that some patients hospitalized for psychiatric disorders have underlying B12 deficiency. Treatment with B12 supplements may help improve psychiatric symptoms.
Birth defects
Pregnant women with critically low B12 levels carry an increased risk of neural tube defects in their babies. Supplementing helps lower this risk. Untreated deficiency in infants can also lead to permanent neurological damage and developmental delays.
Heart disease and stroke
Some research links low vitamin B12 levels with up to a 35% higher risk of cardiovascular issues like heart attack, stroke, and high blood pressure. Scientists think deficiency may promote buildup of homocysteine, an inflammatory factor that damages blood vessels.
Cancer
There is some evidence that vitamin B12 deficiency may be associated with an increased risk of certain cancers, including breast, lung, cervical, and colon cancers. More research is needed to confirm this link. One theory is that lack of B12 causes faulty DNA synthesis and repair.
Megaloblastic anemia
Without enough vitamin B12, the body struggles to make enough healthy red blood cells. This leads to a condition called megaloblastic or pernicious anemia, characterized by enlarged, malformed red blood cells. Symptoms include dizziness, shortness of breath, rapid heartbeat, and extreme fatigue.
When should I see a doctor?
You should see a doctor if you have any persistent symptoms of vitamin B12 deficiency, especially neurological symptoms like tingling/numbness, walking difficulties, disorientation, or memory loss. Timely diagnosis and treatment is crucial to prevent irreversible damage.
See a doctor right away if you have fatigue along with shortness of breath or dizziness, as this may indicate anemia. Severe B12 deficiency needs treatment with B12 injections, as oral supplements may not be absorbed. People over 50 should have their B12 levels checked during routine exams since deficiency is common in older adults.
How is vitamin B12 deficiency diagnosed?
A blood test checking your vitamin B12 levels can definitively diagnose a deficiency. Levels below 200 pg/mL indicate a deficiency. Levels between 200-350 pg/mL are considered borderline low. Your doctor may also order tests for methylmalonic acid and homocysteine, as elevated levels can confirm a B12 deficiency.
A complete blood count can check for anemia. Bone marrow testing may sometimes be needed to check for megaloblastic anemia caused by low B12. Your doctor may also do neurological exams to check for signs of nerve damage.
What is the treatment for vitamin B12 deficiency?
Treatment for B12 deficiency usually involves supplemental B12 given through:
Oral supplements
This may include high-dose B12 pills or sublingual tablets that dissolve under the tongue. These allow your body to absorb B12 directly into the bloodstream. This route works well unless you have absorption issues in the digestive tract.
Intramuscular injections
B12 shots are needed for people who have trouble absorbing the vitamin from digestive tract. Typically, injections are given once per week for 8 weeks to replenish B12 stores, then once a month for maintenance. Most people start feeling better within a few days of starting injections.
Improved diet
If the deficiency is due to poor diet, eating more vitamin B12-rich foods like meat, eggs, and dairy can help restore levels. Nutritional yeast can also help vegans/vegetarians get adequate B12. Taking chewable supplements with meals also boosts absorption.
Most people make a full recovery within 6 weeks to 6 months after starting B12 replacement therapy. Nerve damage can take longer to improve or may be permanent if extensive. It’s crucial to get treated as early as possible to prevent lasting effects. Lifelong maintenance therapy is usually required, either through supplements or periodic injections.
How can I prevent vitamin B12 deficiency?
You can help avoid vitamin B12 deficiency by:
– Eating B12-rich foods like meat, poultry, fish, eggs, and dairy products. If you follow a strict vegan diet, take a B12 supplement or eat foods fortified with B12.
– Taking B12 supplements, especially if over age 50. The pills or sublingual forms are typically easier to absorb than vitamin tablets.
– Getting enough stomach acid. Talk to your doctor if you take antacid medications long-term. Low stomach acid impairs vitamin B12 absorption.
– Getting screened during routine exams if at risk for deficiency. This includes seniors, vegetarians, and those with digestive conditions.
– Seeing a doctor promptly if experiencing potential B12 deficiency symptoms like fatigue, numbness or gait problems. Early diagnosis and correction helps prevent permanent effects.
Conclusion
Vitamin B12 deficiency most often develops slowly over many months and years. The early signs can be subtle, so diagnosis is often delayed until more severe symptoms emerge. Prolonged and severe B12 deficiency can lead to permanent debilitating effects like nerve damage, dementia, and developmental delays in children.
Thankfully, most cases can be reversed with prompt B12 replacement therapy. Lifelong treatment is usually needed though, given poor absorption as we age. Protect yourself by eating B12-rich foods, taking supplements if deficient, and having your levels tested during routine exams. This helps ensure you get adequate B12 over time to support optimal nervous system health.