What happens when you take too much vitamin d
Pro Research Analysisby 
Searched over 200M research papers
Effects of Excessive Vitamin D Intake: A Comprehensive Overview
Introduction to Vitamin D Toxicity
Vitamin D is essential for maintaining bone health and calcium homeostasis. However, excessive intake can lead to vitamin D toxicity, also known as hypervitaminosis D. This condition, although rare, can have severe health implications if not promptly identified and managed1 2.
Clinical Symptoms of Vitamin D Toxicity
Common Symptoms
The most frequently reported symptoms of vitamin D toxicity include confusion, apathy, recurrent vomiting, abdominal pain, polyuria (excessive urination), polydipsia (excessive thirst), and dehydration2 7. These symptoms are primarily due to the resultant hypercalcemia (elevated calcium levels in the blood), which is a hallmark of vitamin D toxicity2.
Severe Manifestations
In severe cases, patients may present with extremely high serum vitamin D concentrations (ranging from 150 to 1220 ng/mL) and serum calcium concentrations (ranging from 11.1 to 23.1 mg/dL). Such levels can lead to more serious conditions like acute kidney injury, cardiac injury, and even life-threatening complications1 5.
Causes of Vitamin D Toxicity
Overdosing and Manufacturing Errors
Vitamin D toxicity often results from excessive long-term intake of vitamin D supplements, either due to overdosing by patients or prescribers, or manufacturing errors1 2. For instance, one case reported a patient consuming 50,000 IU of vitamin D daily for a year, leading to severe hypercalcemia and cardiac injury4.
Metabolic Pathway Malfunctions
Endogenous vitamin D toxicity can also occur due to malfunctions in the vitamin D metabolic pathway. This includes excessive production of active vitamin D metabolites in conditions like granulomatous disorders and certain lymphomas, or reduced degradation of these metabolites in idiopathic infantile hypercalcemia2.
Individual Variability in Response
Case Studies Highlighting Variability
Individual responses to high doses of vitamin D can vary significantly. For example, one patient developed severe symptoms after consuming high doses of vitamin D, while another patient with similar intake levels did not exhibit any symptoms of toxicity4. This variability underscores the complexity of defining a universally toxic dose of vitamin D.
Long-term Effects and Risks
Hypercalcemia and Hypercalciuria
Long-term high-dose vitamin D supplementation has been associated with an increased risk of hypercalcemia and hypercalciuria (elevated calcium in urine), which can lead to tissue and organ damage even without overt hypervitaminosis D3 8. These conditions are early indicators of vitamin D intoxication and necessitate careful monitoring.
Pediatric Considerations
In children, vitamin D toxicity is rare but can occur due to errors in manufacturing or prescription. Severe cases present with hypercalcemia, hypercalciuria, or nephrocalcinosis (calcium deposits in the kidneys). Monitoring vitamin D levels in children receiving high doses is recommended to prevent such adverse effects10.
Conclusion
While vitamin D is crucial for health, excessive intake can lead to serious toxicity. Symptoms range from mild gastrointestinal disturbances to severe hypercalcemia and organ damage. Both patients and healthcare providers should be aware of the potential risks associated with high-dose vitamin D supplementation and ensure appropriate dosing and monitoring to prevent toxicity.
Sources and full results
Most relevant research papers on this topic
Development of Vitamin D Toxicity from Overcorrection of Vitamin D Deficiency: A Review of Case Reports
Vitamin D intoxication is rare but can occur due to manufacturing errors, overdosing by patients or prescribers, and combinations of these factors.
Systematic Review
Very Rigorous Journal
Highly CitedVitamin D Toxicity–A Clinical Perspective
Vitamin D toxicity (VDT) can result from excessive long-term intake of vitamin D, malfunctions in the vitamin D metabolic pathway, or coincidental diseases, and can cause severe health effects if not identified and treated promptly.
Highly CitedCan adverse effects of excessive vitamin D supplementation occur without developing hypervitaminosis D?
Excessive vitamin D supplementation may lead to vitamin D intoxication, causing calcium and phosphorus dysregulation, potentially leading to tissue and organ damage without developing hypervitaminosis D.
How much is too much? Two contrasting cases of excessive vitamin D supplementation.
High-dose vitamin D supplementation can lead to different clinical outcomes depending on individual patient pharmacodynamics, making defining a toxic concentration difficult.
Case ReportHow Much Vitamin D is Too Much? A Case Report and Review of the Literature
Vitamin D intoxication is possible at high doses, but intoxication rarely occurs in clinical practice, and patients and clinicians should be aware of potential dangers of overdose.
Case ReportVitamin D and the Athlete: Current Perspectives and New Challenges
High-dose vitamin D supplementation in athletes may be problematic, and data on ethnicity and vitamin D levels may require re-examination to establish new thresholds and target concentrations.
Rigorous JournalHighly CitedVitamin D Toxicity: A Clinical Perspective
Vitamin D toxicity (VDT) is caused by excessive long-term intake of vitamin D, malfunctions in the vitamin D metabolic pathway, or coincidental disease, and can result in severe hypercalcemia if not promptly identified.
Highly CitedAdverse events from large dose vitamin D supplementation taken for one year or longer
Long-term high-dose vitamin D supplementation did not significantly increase the risk of total adverse events or kidney stones, but there was a trend towards increased hypercalcemia and possibly hypercalciuria.
Systematic ReviewVitamin D supplementation guidelines
Higher vitamin D levels are associated with improved outcomes for various chronic diseases, and supplementation is recommended based on individual factors like age, body weight, and latitude.
Highly CitedVitamin D supplementation and risk of toxicity in pediatrics: a review of current literature.
Vitamin D toxicity in children is rare but life-threatening, and monitoring levels is recommended for infants receiving long-term supplementation at or above the recommended upper intake.
Systematic ReviewRigorous JournalHighly Cited