Take vitamin D with or before evening meal

Get perhaps 50% more benefit of Vitamin D by taking with or before evening meal

Apparently supplements/pills taken just after the last meal of the day have the longest time to be absorbed in the gut

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See also at VitaminDWiki:

• How you might double the benefit of your vitamin D
• Items in category "How/When to Take" 54 items
• Increased vitamin D in blood by 56% by taking supplement with largest meal of the day - May 2010
  • 2010 research found that you get far more benefit from vitamin D when it is taken with the largest meal of the day (probably 5 to 7 PM)

Conversion from conventional to nocturnal hemodialysis improves vitamin D levels.

Kidney Int. 2007 Jun;71(11):1172-6. Epub 2007 Mar 28.
Nessim SJ, Jassal SV, Fung SV, Chan CT.
Department of Medicine, Division of Nephrology, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.

Patients on conventional hemodialysis have low levels of 25-hydroxy-vitamin D probably due to diet and decreased cutaneous synthesis. As 1,25 dihydroxy-vitamin D synthesis is substrate-dependent in end-stage renal disease, this could be a contributing factor to low 1,25 dihydroxy-vitamin D levels in patients undergoing conventional hemodialysis. We converted 35 patients historically on conventional hemodialysis to nocturnal hemodialysis for a minimum of 6 months thereby significantly increasing sessional equilibrated Kt/V from an average of 1.30 to an average of 2.01. Dietary restrictions were also removed. Serum phosphorus significantly fell, whereas the serum calcium, parathyroid hormone, and the mean dose of calcitriol did not change after the conversion. Significant increases in both 25-hydroxy and 1,25-dihydroxy-vitamin D levels were seen after hemodialysis mode conversion. A significant correlation was found between the dialysis dose and the levels of both hydroxylated forms of vitamin D. We suggest that improving uremia by nocturnal hemodialysis in the absence of exogenous supplementation is associated with increased 25 and 1,25-hydroxy-vitamin D levels. Additionally, normalization of serum phosphorus may improve 1alpha-hydroxylation thereby enhancing substrate-dependent generation of 1,25-dihydroxy-vitamin D in chronic dialysis patients. PMID: 17396116

Diurnal rhythm of plasma 1,25-dihydroxyvitamin D and vitamin D-binding protein in postmenopausal women: relationship to plasma parathyroid hormone and calcium and phosphate metabolism.

Eur J Endocrinol. 2002 May;146(5):635-42.
Rejnmark L, Lauridsen AL, Vestergaard P, Heickendorff L, Andreasen F, Mosekilde L.
Department of Endocrinology and Metabolism C, Aarhus Amtssygehus, Aarhus University Hospital, Denmark. rejnmark at post6.tele.dk

OBJECTIVE: Diurnal variations in plasma levels of 1,25-dihydroxyvitamin D (1,25(OH)(2)D) have previously only been investigated in young individuals, and these studies have failed to demonstrate a diurnal rhythm. We have studied whether plasma levels of 1,25(OH)(2)D and vitamin D-binding protein (DBP) vary in a diurnal rhythm in postmenopausal women.

METHODS: Blood and urine were sampled with 2- and 4-h intervals in order to assess diurnal variations in plasma levels of 1,25(OH)(2)D, DBP and parathyroid hormone (PTH), as well as in plasma levels and urinary excretion rates of calcium and phosphate. Additionally, the free 1,25(OH)(2)D index was calculated (the molar ratio of 1,25(OH)(2)D to DBP).

RESULTS: Plasma 1,25(OH)(2)D exhibited a diurnal rhythm (P<0.01) with a nadir in the morning (99+/-12 pmol/l), followed by a rapid increase to a plateau during the day (113+/-13 pmol/l, i.e. 14% above nadir level; P=0.005). A similar pattern of variation was found in plasma levels of DBP with peak levels 15% above nadir levels (P<0.01). The free 1,25(OH)(2)D index did not vary in a diurnal rhythm. PTH and plasma levels and urinary excretions of calcium and phosphate exhibited a diurnal pattern of variation. The diurnal rhythm of DBP was correlated with the rhythm of 1,25(OH)(2)D (r=0.47, P<0.01) and plasma albumin (r=0.76, P<0.01). Moreover, the rhythm of plasma calcium and PTH varied inversely (r=-0.36, P=0.02).

CONCLUSIONS: With the disclosure of a diurnal rhythm of total plasma 1,25(OH)(2)D, all major hormones and minerals related to calcium homeostasis have now been shown to exhibit diurnal variations. In clinical studies, the diurnal variations of 1,25(OH)(2)D and DBP must be considered, i.e. blood sampling must be standardised according to the time of day. PMID: 11980618

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Chronotherapy of high-dose active Vitamin D(3): is evening dosing preferable?

Pediatr Nephrol. 2004 Jul;19(7):722-3.
Sanchez CP.
University of Wisconsin Medical School, Madison, WI 53706, USA. cpsanchez at wisc.edu

Oral Vitamin D(3) is usually administered to children with chronic renal failure in the morning. Is there enough evidence that evening dosing is more beneficial with respect to suppression of parathyroid hormone and reduction of side effects such as hypercalcemia? PMID: 15266665

Chronotherapy of high-dose active vitamin D3 in haemodialysis patients with secondary hyperparathyroidsm: a repeated dosing study.

Br J Clin Pharmacol. 2003 Jun;55(6):531-7.
Tsuruoka S, Wakaumi M, Sugimoto K, Saito T, Fujimura A.
Department of Clinical Pharmacology, Jichi Medical School, Minamikawachi, Tochigi, and Haemodialysis Unit, Moka Hospital, Moka, Tochigi, Japan. tsuru at jichi.ac.jp

AIMS: Renal osteodystrophy is the major complication in patients with end-stage renal failure. Oral or intravenous vitamin D3 (D3) is given to these patients, but severe hypercalcaemia sometimes interrupts this therapy. This study was undertaken to determine whether the effectiveness and safety of D3 also depend on its dosing time during a repeated treatment.

METHODS: A higher dose (3 micro g) was given orally to 13 haemodialysis patients at 08.00 h or 20.00 h for 12 months by a randomized, cross-over design.

RESULTS: Three patients were withdrawn due to severe hypercalcaemia after switching from 08.00 h to 20.00 h dosings. The elevation in serum calcium concentration was significantly (P < 0.001) greater during the 08.00 h dosing in the remaining ten patients. Mean serum Ca concentration after the trial was 10.92 (95% confidence interval (CI) 10.79, 11.06) and 9.55 mg dl-1 (95% CI 9.30, 9.71) by 08.00 h and 20.00 h dosing, respectively. On the other hand, the suppression of the elevated serum parathyroid hormone (PTH) and subsequent increment in bone density were significantly greater during the 08.00 h dosing. Mean PTH concentration after the trial was 414 (95% CI 360, 475) and 220 pg ml-1 (95% CI 202, 249) by 08.00 h and 20.00 h dosing, respectively (P = 0.02). Mean increment of bone density after the trial was 22 (95% CI 8, 32) and 57 g cm-3 (95% CI 43, 83) by 08.00 h and 20.00 h dosing, respectively (P = 0.04).

CONCLUSION: These results indicate that a higher dose of oral D3 is more effective and safe after dosing at evening in patients with renal osteodystrophy.

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