How long does it take vitamin d to work
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How Long Does It Take Vitamin D to Work?
Vitamin D is essential for various bodily functions, including bone health, immune function, and cognitive performance. Understanding how long it takes for vitamin D to work can help in managing expectations and optimizing supplementation strategies.
Biological Half-Life of Vitamin D
The biological half-life of vitamin D in human plasma is a critical factor in determining how long it takes to see its effects. Estimates suggest that the half-life of vitamin D does not exceed 50 hours based on short-term observations1. However, after administering large amounts of vitamin D, its activity in plasma can persist for much longer, with a half-time that may exceed three months1. This indicates that while initial effects might be observed relatively quickly, the full benefits of vitamin D supplementation can take several months to manifest.
Cognitive Function Improvement
A study on older adults with mild cognitive impairment (MCI) found that vitamin D supplementation (800 IU/day) over 12 months significantly improved cognitive function2. Improvements were noted in various cognitive tests, and the benefits were mediated through mechanisms involving reduced oxidative stress and increased telomere length2. This suggests that for cognitive benefits, a longer duration of consistent supplementation is necessary.
Rapid Effects on Calcium Transport
Vitamin D metabolites can have rapid effects on calcium transport. In vitamin D-deficient rats, a vitamin D metabolite stimulated intestinal calcium transport within 8-10 hours after oral administration, whereas vitamin D itself required about 20 hours to show similar effects3. This indicates that some physiological effects of vitamin D can be observed within a day of supplementation.
Recovery from COVID-19 Symptoms
In patients with mild to moderate COVID-19, a higher dose of vitamin D3 (5000 IU/day) for two weeks significantly reduced the time to recovery for symptoms like cough and loss of taste compared to a lower dose (1000 IU/day)4. This demonstrates that higher doses of vitamin D can lead to quicker symptomatic relief in certain conditions.
Synthesis and Release from Skin
Vitamin D synthesis in the skin, triggered by exposure to ultraviolet radiation, involves a process that takes at least three days to complete5. The synthesized vitamin D3 is then slowly released into the circulation, indicating a gradual onset of its effects when obtained through sunlight exposure.
Long-Term Benefits and Longevity
High-dose vitamin D treatment over seven weeks has been shown to reduce the need for infliximab dose escalation and decrease inflammatory markers in Crohn’s disease patients over a one-year follow-up period6. Additionally, vitamin D3 supplementation (400 IU or 1000 IU daily) showed benefits in maintaining adequate vitamin D levels even two years after cessation of supplementation8. This highlights the long-term benefits and lasting effects of consistent vitamin D supplementation.
Monthly Increase in Vitamin D Levels
A pilot study found that daily supplementation with 2000 IU of vitamin D3 led to a significant increase in plasma vitamin D levels within one month9. Most participants showed improved vitamin D status, with a median increase of 8.85 ng/mL after 28 days9. This indicates that noticeable improvements in vitamin D levels can be achieved within a month of starting supplementation.
Conclusion
The time it takes for vitamin D to work can vary depending on the specific health outcome being targeted. While some effects, such as improved calcium transport, can be observed within hours, other benefits, like cognitive function improvement and long-term inflammatory control, may require several months of consistent supplementation. Understanding these timelines can help in setting realistic expectations and optimizing vitamin D supplementation strategies for various health conditions.
Sources and full results
Most relevant research papers on this topic
Vitamin D Supplementation Improves Cognitive Function Through Reducing Oxidative Stress Regulated by Telomere Length in Older Adults with Mild Cognitive Impairment: A 12-Month Randomized Controlled Trial.
Vitamin D supplementation for 12 months improves cognitive function in older adults with mild cognitive impairment by reducing oxidative stress regulated by telomere length.
RCT
Rigorous JournalBiological activity of a vitamin D metabolite
A vitamin D metabolite, found in rat carcasses, effectively cures rickets, stimulates intestinal calcium transport, and increases serum calcium levels, with a shorter lag time compared to vitamin D.
Highly CitedEffects of a 2-Week 5000 IU versus 1000 IU Vitamin D3 Supplementation on Recovery of Symptoms in Patients with Mild to Moderate Covid-19: A Randomized Clinical Trial
Daily 5000 IU oral vitamin D3 supplementation for 2 weeks reduces the time to recovery for cough and gustatory sensory loss in patients with mild to moderate COVID-19 and suboptimal vitamin D status.
RCT
Very Rigorous JournalHighly CitedPhotosynthesis of previtamin D3 in human skin and the physiologic consequences.
Photosynthesis of previtamin D3 in human skin occurs when exposed to solar ultraviolet radiation, and its slow, steady release into the circulation is a unique mechanism for vitamin D3 synthesis, storage, and release.
Highly CitedSeven Weeks of High-Dose Vitamin D Treatment Reduces the Need for Infliximab Dose-Escalation and Decreases Inflammatory Markers in Crohn’s Disease during One-Year Follow-Up
High-dose vitamin D treatment for seven weeks reduces the need for infliximab dose-escalation and decreases inflammatory markers in Crohn's disease patients during one-year follow-up.
RCTVery Rigorous JournalBioavailability of vitamin D(2) and D(3) in healthy volunteers, a randomized placebo-controlled trial.
Vitamin D3 increases total 25(OH)D concentration more than vitamin D2, while vitamin D2 supplementation leads to a decrease in 25(OH)D3, explaining the different effect on total 25(OH)D.
RCTRigorous JournalHighly CitedLongevity of daily oral vitamin D3 supplementation: differences in 25OHD and 24,25(OH)2D observed 2 years after cessation of a 1-year randomised controlled trial (VICtORy RECALL)
Daily vitamin D3 supplementation shows benefits over placebo 2 years after discontinuing treatment, with vitamin D-binding protein being a predictor of vitamin D longevity.
RCTRigorous JournalMonthly Increase in Vitamin D Levels upon Supplementation with 2000 IU/Day in Healthy Volunteers: Result from “Integriamoci”, a Pilot Pharmacokinetic Study
Vitamin D levels can increase rapidly after daily supplementation with 2000 IU/day, reducing deficiency in 62% of healthy volunteers after 28 days.
Non-RCTThe effect of vitamin D supplementation on glycemic status of elderly people with prediabetes: a 12-month open-label, randomized-controlled study
Vitamin D supplementation can improve glycemic status in elderly people with prediabetes, potentially complementing lifestyle changes in managing this condition.
RCT