From the Guidelines
Vitamin B12 toxicity is generally asymptomatic, but when symptoms occur, they may include clinical signs or symptoms compatible with toxicity, such as acne, rosacea, itchy skin rashes, headaches, anxiety, nausea, vomiting, diarrhea, and dizziness, as the intestinal mucosa is bypassed in intravenous administration 1. The definition of toxicity, as per the ESPEN micronutrient guideline, is the presence of clinical signs or symptoms compatible with toxicity, with a history of intake of amounts considered unsafe or toxic 1. According to the guideline, overdose is generally asymptomatic, but may occur in the context of repeated micronutrient administration, particularly in patients with diseases reducing elimination, such as liver and renal disease 1. Key points to consider in vitamin B12 toxicity include:
- The risk of toxicity is highest with intravenous administration, as the intestinal mucosa is bypassed 1
- Clinical signs or symptoms are generally present in toxicity, but may be absent in overdose 1
- The diagnosis of toxicity is most frequently based on blood levels 1
- Discontinuing supplements and consulting a healthcare provider is recommended if toxicity is suspected 1
From the Research
Signs and Symptoms of Vitamin B12 Toxicity
There are no research papers to assist in answering this question, as the provided studies focus on vitamin B12 deficiency rather than toxicity.
Related Information on Vitamin B12
- The provided studies discuss the diagnosis, treatment, and management of vitamin B12 deficiency, including its causes, symptoms, and consequences 2, 3, 4, 5.
- High serum levels of vitamin B12, also known as hypervitaminosis B12, can be caused by various factors, including solid neoplasia, hematological diseases, liver disorders, and excess vitamin B12 intake 6.
- However, the studies do not provide information on the signs and symptoms of vitamin B12 toxicity, as they primarily focus on deficiency rather than excess.
Key Points on Vitamin B12 Deficiency
- Vitamin B12 deficiency can cause variable symptoms, including macrocytic anemia, pancytopenia, and hemolytic anemia 4.
- Elevated homocysteine levels can lead to thrombus formation and potentially life-threatening complications 4.
- Diagnosis and treatment of vitamin B12 deficiency depend on the cause and severity of the deficiency, as well as individual patient factors 2, 3, 5.