How long does it take for vitamin d to work

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How Long Does It Take for Vitamin D to Work?

Introduction to Vitamin D Efficacy

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 exhibit its effects can help in managing expectations and optimizing supplementation strategies.

Cognitive Function Improvement in Older Adults

A study on older adults with mild cognitive impairment (MCI) demonstrated that vitamin D supplementation (800 IU/day) over 12 months significantly improved cognitive function. The improvements were observed in various cognitive tests, including full-scale intelligence quotient (FSIQ) and memory-related tasks. These cognitive benefits were linked to reduced oxidative stress and increased telomere length .

Biological Half-Life and Longevity of Vitamin D

The biological half-life of vitamin D in human plasma is complex. Initial estimates suggested a half-life of around 50 hours, but other studies indicate that the "vitamin D activity" in plasma can persist for up to three months after large doses . Additionally, vitamin D3 synthesized in the skin is released slowly into the circulation, taking at least three days to complete its thermal isomerization process .

Short-Term Effects on Inflammatory Markers

In patients with Crohn's disease, a high-dose vitamin D treatment (5 mg bolus followed by 0.5 mg/day for seven weeks) significantly reduced the need for infliximab dose escalation and decreased inflammatory markers over a one-year follow-up period . This suggests that even short-term high-dose vitamin D supplementation can have lasting anti-inflammatory effects.

Rapid Symptom Recovery in COVID-19 Patients

A study on COVID-19 patients with sub-optimal vitamin D status found that a higher dose of vitamin D3 (5000 IU/day) for two weeks significantly accelerated the recovery of symptoms such as cough and loss of taste compared to a lower dose (1000 IU/day). This indicates that vitamin D can start showing beneficial effects within a short period, particularly in acute conditions .

Glycemic Control in Prediabetic Elderly

In elderly individuals with prediabetes, vitamin D supplementation (25,000 IU weekly) over 12 months improved glycemic markers, including fasting glucose and glycated hemoglobin levels. Significant improvements were observed as early as six months into the supplementation .

Long-Term Benefits Post-Supplementation

A study examining the longevity of vitamin D status after cessation of supplementation found that the benefits of daily vitamin D3 (400 IU or 1000 IU) persisted for up to two years. The proportion of women with sufficient vitamin D levels remained higher compared to those who received a placebo .

Conclusion

The time it takes for vitamin D to work can vary depending on the condition being treated and the dosage used. Cognitive improvements in older adults with MCI were observed over 12 months, while significant anti-inflammatory effects in Crohn's disease and rapid symptom recovery in COVID-19 patients were noted within weeks. Long-term benefits can persist for years after supplementation ceases, highlighting the importance of consistent vitamin D intake for sustained health benefits.

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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.

RCTRigorous Journal

2020·

61citations

·Tong Yang et al.

Long Biological Half-life of Vitamin D3 and its Polar Metabolites in Human Serum

Vitamin D3 and its polar metabolites have a long biological half-life in human serum, with a half-time of up to 3 months after administration.

1969·

55citations

·E. Mawer et al.

Photosynthesis 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 Cited

1980·

791citations

·M. Holick et al.

Seven 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 Journal

2021·

15citations

·Mia Bendix et al.

Effects 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.

RCTVery Rigorous JournalHighly Cited

2021·

133citations

·S. Sabico et al.

Biological 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 Cited

1967·

79citations

·H. Morii et al.

The 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

2022·

4citations

·E. Zaromitidou et al.

Longevity 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 Journal

2017·

5citations

·H. Macdonald et al.

Bioavailability 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 Cited

2013·

120citations

·Ulrike Lehmann et al.

Vitamin D3 supplementation for 16 weeks improves flow-mediated dilation in overweight African-American adults.

60,000 IU monthly oral vitamin D3 supplementation for 16 weeks effectively improves vascular endothelial function in overweight African-American adults.

RCTHighly Cited

2011·

158citations

·R. Harris et al.

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