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Key Takeaways
- Vitamin B12 deficiency can cause symptoms of anemia, nerve problems, and sensory changes that often resemble other conditions, making diagnosis difficult.
- Most cases are due to low dietary intake or trouble absorbing B12. Diagnosis relies on a thorough medical history, a physical examination, and laboratory testing.
- Treatment usually involves vitamin B12 supplements. An untreated deficiency can cause permanent symptoms and may require long-term rehabilitation.
Vitamin B12 deficiency is common in older adults, vegetarians, vegans, and people with certain medical conditions because the vitamin is mostly found in meat, fish, dairy, and fortified foods. When levels drop, symptoms like fatigue, headaches, muscle weakness, and depression can appear, but diagnosis can be tricky since these overlap with many other conditions.
1. You May Feel Weak and Fatigued
Vitamin B12 plays a role in the production of red blood cells (RBCs). These cells carry oxygen through the body. Oxygen helps your body produce energy.
Vitamin B12 deficiency leads to the production of defective RBCs. Anemia is when you don’t have enough red blood cells. Anemia can make you feel weak and fatigued. Other symptoms include fatigue, dizziness, paleness, and a rapid heart rate.
2. You May Experience Balance Problems
Vitamin B12 is also a vital part of a healthy nervous system. Low B12 can cause the nerves in your brain, spinal cord, and elsewhere in your body to slowly degenerate.
This is called neuropathy, a condition characterized by an impairment in nerve function. It causes tingling, numbness, weakness, and balance problems. These symptoms can be worse if you also have anemia.
3. You May Develop Sensory Issues and Numbness
Myelopathy is damage to the spinal cord. It occurs when neurons in a specific part of the spinal cord deteriorate. Neurons are nerve cells that receive and process information by relaying it to other cells.
This results in muscle weakness, sensory issues, numbness, and tingling. It can also cause difficulties in sensing light touch and vibration.
People with myelopathy may also experience problems with proprioception, the ability to sense and judge their body position, such as knowing how high they’re holding up an arm without looking.
People with this condition may also have neuropathy-like symptoms.
4. Other Symptoms
Other symptoms of vitamin B12 deficiency may include:
- Low white blood cell count, which increases your risk of infection
- Low platelet count, which increases your risk of bleeding
- Headaches
- Weight loss
- Mood changes, especially depression
- Behavioral changes
- Walking problems
- Loss of or diminished sense of smell
- Swollen tongue
Symptoms of vitamin B12 deficiency typically develop gradually over the course of weeks or months. They do not usually improve without treatment.
What Causes Vitamin B12 Deficiency?
Inadequate Intake
Vitamin B12 is found in a variety of food sources. These include:
- Fish
- Meat
- Milk
- Fortified plant-based foods such as fortified plant milks, nutritional yeast, or cereals
Many sources of vitamin B12 come from animal proteins. Because of this, long-term vegetarians or vegans who don’t take B12 supplements are at risk for vitamin B12 deficiency.
The risk is also higher in older people and people who abuse alcohol.
Impaired Absorption
Vitamin B12 is absorbed in the gut with the help of a protein called intrinsic factor. When the process of absorption doesn’t work right, you may develop a B12 deficiency.
Causes of impaired B12 absorption include:
- Pernicious anemia, an autoimmune disorder in which antibodies attack the cells that release intrinsic factor
- Inflammatory gastrointestinal (GI) disorders like Crohn’s disease and celiac disease
- Prolonged use of certain medications, like the diabetes medication metformin and stomach acid-reducing proton pump inhibitors (PPIs)
- Gastric bypass, a weight loss surgery that changes the structure of the stomach
- GI resection surgery, a treatment for serious medical problems like bowel obstruction or cancer
Why Is It Hard to Diagnose?
The diagnosis of vitamin B12 isn’t always obvious. This is because many of the common symptoms overlap with those of other health conditions. Your medical team may consider several diagnoses in addition to B12 deficiency.
Your medical history can help your doctor understand your symptoms. A physical exam may also help identify the signs of B12 deficiency.
For example, a weak, rapid pulse or pale fingers may be a sign of anemia. Signs of neuropathy can include low sensation in your feet and poor reflexes. These signs may be found in other conditions.
Treatment
Vitamin B12 deficiency can be managed with oral or injectable B12 supplements. If a problem with absorption causes your B12 deficiency, you may need an injection. The injection will help the vitamin absorb directly into your bloodstream.
Some patients need lifelong B12 supplementation. This usually depends on the cause of the deficiency. You may need to continue taking B12 supplements even after your symptoms improve.
How Long Does It Take to Recover From Vitamin B12 Deficiency?
Recovery from vitamin B12 deficiency takes time. You may not have any improvement during the first few months of treatment. Improvement may be gradual.