Three Studies Emphasizing Importance of Vitamin D

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Hi Folks:

1.

Why the optimal requirement for Vitamin D(3) is probably much higher

than what is officially recommended for adults.

Vieth R.

Department of Laboratory Medicine and Pathobiology, University of

Toronto, and Pathology and Laboratory Medicine, Mount Sinai Hospital,

Toronto, Canada M5G 1X5.

The physiologic range for circulating 25-hydroxyvitamin D3 [25(OH)D;

the measure of Vitamin D nutrient status] concentration in humans and

other primates extends to beyond 200nmol/L (>80ng/mL). This

biologic " normal " value is greater than current population norms for

25(OH)D. Concentrations of 25(OH)D that correlate with desirable

effects extend to at least 70nmol/L, with no obvious threshold.

Randomized clinical trials using 20mcg (800IU) per day of Vitamin D

show that this suppresses parathyroid hormone, preserves bone mineral

density, prevents fractures, lowers blood pressure and improves

balance. Calcium absorption from diet correlates with 25(OH)D in the

normal range. Health effects of Vitamin D beyond osteoporosis are

mostly supported by the circumstantial evidence of epidemiologic

studies and laboratory research. These include prevention of cancer

and the autoimmune diseases, insulin-dependent diabetes and multiple

sclerosis. One mcg per day of Vitamin D(3) (cholecalciferol)

increases circulating 25(OH)D by about 1nmol/L (0.4ng/mL). A

recommended dietary allowance (RDA) is the long-term daily intake

level that meets the total requirements for the nutrient by nearly

all healthy individuals (it would presume no sunshine). If 70nmol/L

is regarded as a minimum desirable target 25(OH)D concentration, then

current recommendations of 15mcg per day do not meet the criterion of

an RDA.

PMID: 15225842 [PubMed - in process]

2.

Supplementation with oral vitamin d3 and calcium during winter

prevents seasonal bone loss: a randomized controlled open-label

prospective trial.

Meier C, Woitge HW, Witte K, Lemmer B, Seibel MJ.

Bone Research Program, ANZAC Research Institute, University Sydney,

Concord, New South Wales, Australia.

Bone metabolism follows a seasonal pattern with high bone turnover

and bone loss during the winter. In a randomized, open-label 2-year

sequential follow-up study of 55 healthy adults, we found that

supplementation with oral vitamin D(3) and calcium during winter

abolished seasonal changes in calciotropic hormones and markers of

bone turnover and led to an increase in BMD. Supplementation with

oral vitamin D(3) and calcium during the winter months seems to

counteract the effects of seasonal changes in vitamin D and thus may

be beneficial as a primary prevention strategy for age-related bone

loss. INTRODUCTION: Bone metabolism follows a seasonal pattern

characterized by high bone turnover and bone loss during winter. We

investigated whether wintertime supplementation with oral vitamin D

(3) and calcium had beneficial effects on the circannual changes in

bone turnover and bone mass. MATERIALS AND METHODS: This prospective

study comprised an initial observation period of 12 months ( " year

1 " ), followed by an intervention during parts of year 2. Fifty-five

healthy subjects living in southwestern Germany (latitude, 49.5

degrees N) were randomized into two groups: 30 subjects were assigned

to the treatment group and received oral cholecalciferol (500 IU/day)

and calcium (500 mg/day) during the winter months of year 2 (October-

April), while 25 subjects assigned to the control group obtained no

supplements. Primary endpoints were changes in calciotropic hormones

[serum 25(OH)D, 1,25(OH)(2)D, and parathyroid hormone], markers of

bone formation (serum bone-specific alkaline phosphatase) and of bone

resorption (urinary pyridinoline and deoxypyridinoline), and changes

in lumbar spine and femoral neck BMD. RESULTS: Forty-three subjects

completed the study. During year 1, calciotropic hormones, markers of

bone turnover, and BMD varied by season in both groups. During the

winter months of year 1, bone turnover was significantly accelerated,

and lumbar spine and femoral BMD declined by 0.3-0.9%. In year 2,

seasonal changes in calciotropic hormones and markers of bone

turnover were either reversed or abolished in the intervention group

while unchanged in the control cohort. In the subjects receiving oral

vitamin D(3) and calcium, lumbar and femoral BMD increased

significantly (lumbar spine: +0.8%, p = 0.04 versus year 1; femoral

neck: +0.1%, p = 0.05 versus year 1), whereas controls continued to

lose bone (intervention group versus control group: lumbar spine, p =

0.03; femoral neck, p = 0.05). CONCLUSIONS: Supplementation with oral

vitamin D(3) and calcium during winter prevents seasonal changes in

bone turnover and bone loss in healthy adults. It seems conceivable

that annually recurring cycles of low vitamin D and mild secondary

hyperparathyroidism during the winter months contributes, at least in

part and over many years, to age-related bone loss. Supplementation

with low-dose oral vitamin D(3) and calcium during winter may be an

efficient and inexpensive strategy for the primary prevention of bone

loss in northern latitudes.

PMID: 15231008 [PubMed - in process]

3.

Association between serum concentrations of 25-hydroxyvitamin D3 and

periodontal disease in the US population.

Dietrich T, Joshipura KJ, Dawson- B, Bischoff-Ferrari HA.

Department of Periodontology and the Department of Oral Surgery and

Oral Radiology, Charite, Humboldt University of Berlin, Germany.

tdietric@...

BACKGROUND: Periodontal disease (PD) is a common chronic inflammatory

disease and an important risk factor for tooth loss. Vitamin D might

affect periodontal disease risk via an effect on bone mineral density

(BMD) or via immunomodulatory effects. OBJECTIVE: The objective was

to evaluate whether serum 25-hydroxyvitamin D(3) [25(OH)D(3)]

concentrations are associated with PD in the third National Health

and Nutrition Examination Survey. DESIGN: We analyzed data on

periodontal attachment loss (AL) and serum 25(OH)D(3) concentrations

from 11 202 subjects aged > or =20 y. Mean AL was modeled in a

multiple linear regression with quintile of serum 25(OH)D(3)

concentration as an independent variable. The model was stratified by

age and sex and was adjusted for age within age groups, race or

ethnicity, smoking, diabetes, poverty income ratio, body mass index,

estrogen use, and gingival bleeding. RESULTS: 25(OH)D(3)

concentrations were significantly and inversely associated with AL in

men and women aged > or =50 y. Compared with men in the highest 25(OH)

D(3) quintile, those in the lowest quintile had a mean AL that was

0.39 mm (95% CI: 0.17, 0.60 mm) higher; in women, the difference in

AL between the lowest and highest quintiles was 0.26 mm (0.09, 0.43

mm). In men and women younger than 50 y, there was no significant

association between 25(OH)D(3) and AL. The BMD of the total femoral

region was not associated with AL and did not mediate the association

between 25(OH)D(3) and AL. CONCLUSIONS: Low serum 25(OH)D(3)

concentrations may be associated with PD independently of BMD. Given

the high prevalence of PD and vitamin D deficiency, these findings

may have important public health implications.

PMID: 15213036 [PubMed - indexed for MEDLINE]