J
John Que
Guest
1: J Clin Endocrinol Metab. 2004 Nov;89(11):5387-91.
Vitamin D2 is much less effective than vitamin D3 in humans.
Armas LA, Hollis BW, Heaney RP.
Creighton University, 601 North 30th Street, Suite 4841, Omaha, Nebraska
68131,
USA.
Vitamins D(2) and D(3) are generally considered to be equivalent in humans.
Nevertheless, physicians commonly report equivocal responses to seemingly
large
doses of the only high-dose calciferol (vitamin D(2)) available in the U.S.
market.The relative potencies of vitamins D(2) and D(3) were evaluated by
administering single doses of 50,000 IU of the respective calciferols to 20
healthy male volunteers, following the time course of serum vitamin D and
25-hydroxyvitamin D (25OHD) over a period of 28 d and measuring the area
under
the curve of the rise in 25OHD above baseline.The two calciferols produced
similar rises in serum concentration of the administered vitamin, indicating
equivalent absorption. Both produced similar initial rises in serum 25OHD
over
the first 3 d, but 25OHD continued to rise in the D(3)-treated subjects,
peaking
at 14 d, whereas serum 25OHD fell rapidly in the D(2)-treated subjects and
was
not different from baseline at 14 d. Area under the curve (AUC) to d 28 was
60.2
ng.d/ml (150.5 nmol.d/liter) for vitamin D(2) and 204.7 (511.8) for vitamin
D(3)
(P < 0.002). Calculated AUC(infinity) indicated an even greater
differential,
with the relative potencies for D(3)
(2) being 9.5:1.Vitamin D(2) potency
is
less than one third that of vitamin D(3). Physicians resorting to use of
vitamin
D(2) should be aware of its markedly lower potency and shorter duration of
action relative to vitamin D(3).
PMID: 15531486 [PubMed - in process]
Vitamin D2 is much less effective than vitamin D3 in humans.
Armas LA, Hollis BW, Heaney RP.
Creighton University, 601 North 30th Street, Suite 4841, Omaha, Nebraska
68131,
USA.
Vitamins D(2) and D(3) are generally considered to be equivalent in humans.
Nevertheless, physicians commonly report equivocal responses to seemingly
large
doses of the only high-dose calciferol (vitamin D(2)) available in the U.S.
market.The relative potencies of vitamins D(2) and D(3) were evaluated by
administering single doses of 50,000 IU of the respective calciferols to 20
healthy male volunteers, following the time course of serum vitamin D and
25-hydroxyvitamin D (25OHD) over a period of 28 d and measuring the area
under
the curve of the rise in 25OHD above baseline.The two calciferols produced
similar rises in serum concentration of the administered vitamin, indicating
equivalent absorption. Both produced similar initial rises in serum 25OHD
over
the first 3 d, but 25OHD continued to rise in the D(3)-treated subjects,
peaking
at 14 d, whereas serum 25OHD fell rapidly in the D(2)-treated subjects and
was
not different from baseline at 14 d. Area under the curve (AUC) to d 28 was
60.2
ng.d/ml (150.5 nmol.d/liter) for vitamin D(2) and 204.7 (511.8) for vitamin
D(3)
(P < 0.002). Calculated AUC(infinity) indicated an even greater
differential,
with the relative potencies for D(3)
(2) being 9.5:1.Vitamin D(2) potencyis
less than one third that of vitamin D(3). Physicians resorting to use of
vitamin
D(2) should be aware of its markedly lower potency and shorter duration of
action relative to vitamin D(3).
PMID: 15531486 [PubMed - in process]