Effect of 25-hydroxy-vitamin D3 on intestinal absorption of calcium in normal man and patients with renal failure

Colodro, I; Brickman, Arnold S.; Coburn, Jack W.; Osborn, Terry W.; Norman, Anthony W.

doi:10.1016/0026-0495(78)90013-6

Cited by 47 publications

(13 citation statements)

References 27 publications

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“…As shown in Figure 4, our dose-response data for 25(OH)D are remarkably similar to those reported earlier by Colodro et al (9). Further, as reported above and shown in Fig.…”

Section: Discussionsupporting

confidence: 81%

“…Accordingly, the purposes of the present study were 1) to determine the dose-response relationships of vitamin D and its principal metabolites, using calcium absorption efficiency in healthy young adults as the response variable; 2) to compare the findings with the earlier, provocative results of Colodro et al (9); and 3) to estimate the relative contributions of 25(OH)D and 1,25(OH) 2 D to calcium absorption under physiological conditions.…”

Section: (4 -7)mentioning

confidence: 99%

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Calcium Absorptive Effects of Vitamin D and Its Major Metabolites1

Heaney

Barger-Lux

Dowell

et al. 1997

The Journal of Clinical Endocrinology &Amp; Metabolism

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The absorptive response to graded doses of vitamin D 3 , 25(OH)D, and 1,25(OH) 2 D was measured in healthy adult men after treatment periods of eight, four, and two weeks, respectively. While no relationship was found between baseline absorption and serum vitamin D metabolite levels, all three vitamin D compounds significantly elevated 45 Ca absorption from a 300 mg calcium load given as part of a standard test meal. 1,25(OH) 2 D was active even at the lowest dose (0.5 g/day), and the slope was such that doubling of absorption would occur at an oral dose of approximately 3 g/day. 25(OH)D was also active in elevating absorption and did so without raising total 1,25(OH) 2 D levels. On the basis of the dose response curves for For these reasons, we judged that the relative roles of vitamin D and its metabolites in the normal calcium economy needed to be re-evaluated. Accordingly, the purposes of the present study were 1) to determine the dose-response relationships of vitamin D and its principal metabolites, using calcium absorption efficiency in healthy young adults as the response variable; 2) to compare the findings with the earlier, provocative results of Colodro et al. (9); and 3) to estimate the relative contributions of 25(OH)D and 1,25(OH) 2 D to calcium absorption under physiological conditions. Subjects and Methods SubjectsThe subjects were men who were free of health problems and who took no medications known to affect calcium metabolism or skeletal physiology, as determined by interview. To limit the effects of nonstudy sources of vitamin D, we performed the tests in midwinter and excluded candidates who either reported usual milk consumption of more than 0.47 L/day (16 fl oz/day) or who would be exposed to sunlight (via travel to a sunny climate) during the study or in the preceding month. We accepted several candidates who regularly used daily multivitamins (typically containing 10 g of vitamin D, equivalent to 400 IU), but who agreed to abstain from them during their participation in the study and for at least one week before entering it. The Creighton University Institutional Review Board approved the protocol, and each subject gave informed consent. After entering, two subjects withdrew for personal reasons. The 116 who finished the study included two Hispanics, three blacks, five subjects of Asian origin, and 106 whites. Table 1 presents data

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“…As shown in Figure 4, our dose-response data for 25(OH)D are remarkably similar to those reported earlier by Colodro et al (9). Further, as reported above and shown in Fig.…”

Section: Discussionsupporting

confidence: 81%

Section: (4 -7)mentioning

confidence: 99%

Calcium Absorptive Effects of Vitamin D and Its Major Metabolites1

Heaney

Barger-Lux

Dowell

et al. 1997

The Journal of Clinical Endocrinology &Amp; Metabolism

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“…Consequently, 25OHD seems to be a better predictor for calcium absorption ef®ciency. Colodro et al (1978) reported that on a molar basis the physiologic activity of 25OHD relative to calcitriol ranges from 1:400 to as much as 1:125 in humans. Considering that serum 25OHD levels are approximately 10 3 times higher than serum calcitriol concentrations (Table 3), seasonal changes in 25OHD levels may well explain differences in fractional calcium absorption rates.…”

Section: Discussionmentioning

confidence: 99%

Seasonal variations in vitamin D status and calcium absorption do not influence bone turnover in young women

1998

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Objective: To evaluate the effect of seasonal variations in UV B-exposure on calcium absorption and bone turnover in young women with the overall goal to assess the potential bene®t of a vitamin D supplementation during wintertime. Design: Cross-sectional study. Setting: Area of Bonn, Germany (51 N). Subjects: Thirty-eight women (24.5 AE 0.5 y) studied in winter and 38 females of the same age (24.7 AE 0.4 y) studied in summer. Results: As estimated by a 4 d food record, both groups had similar dietary calcium and phosphorus intakes (b1200 mgad, respectively) covering actual recommendations. Signi®cant reductions in serum concentrations of 25-hydroxyvitamin D (25OHD) and calcitriol, fractional calcium absorption (Fc 220 , measured by means of a stable strontium test), 24 h urinary calcium and 24 h urinary phosphorus excretion were observed during wintertime. 25OHD but not calcitriol was correlated with Fc 220 values and with 24 h urinary phosphorus excretion. Moreover, Fc 220 was related to 24 h urinary calcium excretion. Fasting 2 h-urinary deoxypyridinoline concentrations (biomarker of bone resorption) and serum levels of carboxyterminal propeptide of type I procollagen (biomarker of bone formation) showed no differences between summer and winter. Conclusions: Our data indicate a decrease in intestinal calcium and phosphorus absorption during wintertime, most likely because of a reduction in serum 25OHD levels. Since bone turnover was not affected by the seasonal differences in mineral metabolism, there is no objective for young women with high calcium intake to supplement vitamin D during wintertime.

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“…Studies in humans have found a molar potency in calcium absorption of at least 1:400 between 25OHD and 1,25(OH) 2 D [7]. The molar ratio between these two metabolites in serum is around 500:1, so as much as 80% of the circulating vitamin D activity of typical serum concentrations in humans would have to be due to 25OHD.…”

Section: Introductionmentioning

confidence: 99%

Food Contents and Biological Activity of 25-Hydroxyvitamin D: A Vitamin D Metabolite to Be Reckoned With?

Ovesen

Brot

Jakobsen³

2003

Ann Nutr Metab

176

114

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Only a limited number of foods naturally contain vitamin D such as fish, meat and offal, and eggs, and milk and dairy products. However, all these foods in addition contain the metabolite 25-hydroxyvitamin D (25OHD). From the few systematic studies which have been performed the food contents of 25OHD in animal foods are usually low but vary. Contents are typically very low in milk and fish (<0.1 µg/100 g), somewhat higher in meat and offal (0.2–0.4 µg/100 g) and up to 1 µg/100 g in egg yolk. It has been demonstrated that 25OHD is absorbed better and faster from the diet than native vitamin D and has metabolic effects of its own in regulating cell growth and calcium metabolism. Thus, the biological activity of 25OHD is greater than that of native vitamin D. However, there is as yet no consensus on the conversion factor that should be used for 25OHD to calculate vitamin D activity. Depending on the testing system used the factor varies from 1.5 to 5. If food contents and the higher potency of 25OHD are not included in dietary intake surveys, true vitamin D intake will be underestimated.

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Effect of 25-hydroxy-vitamin D3 on intestinal absorption of calcium in normal man and patients with renal failure

Cited by 47 publications

References 27 publications

Calcium Absorptive Effects of Vitamin D and Its Major Metabolites1

Calcium Absorptive Effects of Vitamin D and Its Major Metabolites1

Seasonal variations in vitamin D status and calcium absorption do not influence bone turnover in young women

Food Contents and Biological Activity of 25-Hydroxyvitamin D: A Vitamin D Metabolite to Be Reckoned With?

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