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Prevalence of hypovitaminosis D in UK and Holland alarmingly high in winter, urgent need to recommen
Prevalence of hypovitaminosis D in UK and Holland alarmingly high in winter, urgent need to recommen
The study
Hypponen E, Power C.
Hypovitaminosis D in British adults at age 45 y: nationwide cohort
study of dietary and lifestyle predictors.
Am J Clin Nutr. 2007 Mar;85(3):860-8.
PMID: 17344510 [PubMed - in process]
< http :// www .ajcn.org/cgi/content/abstract/85/3/860>
published in the latest issue of AJCN investigated vitamin D status
(serum calcidiol a.k.a (25(OH)D concentrations) of British adults at
age 45 and found that the prevalence of hypovitaminosis D
was alarmingly high during the winter and spring. Below the abstract
of the study:
"BACKGROUND: Increased awareness of the importance of vitamin
D to health has led to concerns about the prevalence of
hypovitaminosis D in many parts of the world. OBJECTIVES: We
aimed to determine the prevalence of hypovitaminosis D in the
white British population and to evaluate the influence of key
dietary and lifestyle risk factors. DESIGN: We measured 25-
hydroxyvitamin D [25(OH)D] in 7437 whites from the 1958
British birth cohort when they were 45 y old. RESULTS: The
prevalence of hypovitaminosis D was highest during the winter
and spring, when 25(OH)D concentrations <25, <40, and <75
nmol/L were found in 15.5%, 46.6%, and 87.1% of participants,
respectively; the proportions were 3.2%, 15.4%, and 60.9%,
respectively, during the summer and fall. Men had higher
25(OH)D concentrations, on average, than did women during the
summer and fall but not during the winter and spring (P 0.006, likelihood ratio test for interaction). 25(OH)D
concentrations were significantly higher in participants who
used vitamin D supplements or oily fish than in those who did
not (P < 0.0001 for both) but were not significantly higher
in participants who consumed vitamin D-fortified margarine
than in those who did not (P = 0.10). 25(OH)D concentrations
<40 nmol/L were twice as likely in the obese as in the
nonobese and in Scottish participants as in those from other
parts of Great Britain (ie, England and Wales) (P < 0.0001
for both). CONCLUSION: Prevalence of hypovitaminosis D in the
general population was alarmingly high during the winter and
spring, which warrants action at a population level rather
than at a risk group level."
In the same issue of AJCN there is a Dutch vitamin D study
van Dam RM, Snijder MB, Dekker JM, Stehouwer CD, Bouter LM, Heine RJ,
Lips P.
Potentially modifiable determinants of vitamin D status in an older
population in the Netherlands: the Hoorn Study.
Am J Clin Nutr. 2007 Mar;85(3):755-761.
PMID: 17344497 [PubMed - as supplied by publisher]
< http :// www .ajcn.org/cgi/content/abstract/85/3/755>,
which found that low vitamin D status among elderly people is very
common also in Holland. Here's its abstract:
"BACKGROUND: Inadequate vitamin D status is common in many
populations around the world. OBJECTIVE: The aim was to
evaluate potentially modifiable determinants of vitamin D
status in an older population. DESIGN: This was a cross-
sectional study from a population-based cohort including 538
white Dutch men and women aged 60-87 y. Vitamin D status was
assessed by plasma 25-hydroxyvitamin D [25(OH)D]
concentrations. RESULTS: In the winter period, 51% of the
subjects had 25(OH)D concentrations <50.0 nmol/L. Greater
body fatness and less time spent on outdoor physical activity
were associated with worse vitamin D status. Regular use of
vitamin D-fortified margarine products [odds ratio (OR) in a
comparison of intake of >/ g/d with none: 0.41; 95% CI:
0.20, 0.86; P for trend < 0.001], fatty fish (OR for servings
of >/=2/mo versus none: 0.41; 95% CI: 0.16, 1.04; P for trend
= 0.01), and vitamin D-containing supplements (OR for >/= 1/d
versus none: 0.33; 95% CI: 0.17, 0.63; P for trend < 0.001)
were inversely associated with vitamin D inadequacy [25(OH)D
<50.0 nmol/L]. We estimated that combined use of margarine
products (20 g/d), fatty fish (100 g/wk), and vitamin D
supplements (>/=1/d) was associated with a 16.8 nmol/L higher
25(OH)D concentration than was the use of none of these.
However, none of the participants reached these intakes for
all 3 factors. CONCLUSION: Because few foods are vitamin D-
fortified and the amounts of vitamin D in supplements are
low, it is difficult to achieve adequate vitamin D status
through increasing intakes in the Netherlands and in
countries with similar policies."
The editorial of the same issue,
Vieth R, Bischoff-Ferrari H, Boucher BJ, Dawson-Hughes B, Garland CF,
Heaney RP, Holick MF, Hollis BW, Lamberg-Allardt C, McGrath JJ, Norman
AW, Scragg R, Whiting SJ, Willett WC, Zittermann A.
The urgent need to recommend an intake of vitamin D that is effective.
Am J Clin Nutr. 2007 Mar;85(3):649-50.
PMID: 17344484 [PubMed - in process]
< http :// www .ajcn.org/cgi/content/full/85/3/649>,
whose list of authors is packed with the most famous and appreciated
vitamin D researchers and also includes Harvard's Walter C. Willett,
comments the study by Hyppönen and Power, states the urgent need to
raise vitamin D recommendations, and appeals to the authorities and
other policy makers, media, vitamin manufacturers, etc., to work for
this goal to get that done as soon as possible. Below a couple of
excerpts from this article:
"The report by Hyppönen and Power in this issue of the
Journal (1) highlights a frustrating and regrettable
situation for nutrition researchers. In the early 1970s, the
same serum 25-hydroxyvitamin D [25(OH)D] concentrations
reported by Hyppönen and Power were thought to be indicative
of "healthy" white adults in the United Kingdom (2). However,
during those early years after the discovery of 25(OH)D, the
adequacy of its serum concentration was based simply on
whether the concentration was enough to prevent osteomalacia
or rickets. Three decades later, we know that 25(OH)D
concentrations relate to many other aspects of health,
including fracture risk, bone density, colon cancer, and even
tooth attachment (3); we also know that much higher
concentrations of 25(OH)D are needed to prevent adverse
outcomes. Indeed, in the 1958 British birth cohort, lower
25(OH)D is associated with a higher percentage of hemoglobin
A1C (a measure of long-term glucose concentration), which
further emphasizes the need to maintain optimal 25(OH)D
concentrations (4).
[...]
It is important for major journals such as the AJCN to
publish evidence of a widespread nutrient deficiency.
Regrettably, we are now stuck in a revolving cycle of
publications that are documenting the same vitamin D
inadequacy (1-3, 5, 7-9, 13-17). This phenomenon has been
referred to as "circular epidemiology" (18), and, for vitamin
D, the phenomenon will continue for as long as the levels of
vitamin D fortification and supplementation and the practical
advice offered to the public remain essentially the same as
they were in the era before we knew that 25(OH)D even
existed. As scientists, the purpose of our work is to improve
the health of the public. We know the realities of serum
25(OH)D concentrations in populations around the world, and
we have come to the conclusion that public health will
benefit from improved vitamin D nutritional status. We know
the intakes of vitamin D needed to bring about desirable
25(OH)D concentrations, so why is the science not making a
difference to public health? A major reason is that there is
little public pressure on policy makers to support efforts to
update recommendations about nutrition. Public pressure is
generally rooted in the media, but we do not think that the
public media present the vitamin D story in a complete and
accurate manner. Reports about vitamin D inadequacies are
presented straightforwardly, but, when it comes to discussing
the intake of vitamin D needed to correct the situation,
outdated official recommendations for vitamin D are
propagated by the public media. This probably occurs because
of restrictive editorial policies driven by concern about
possible litigation if media were to advise a "toxic" intake
greater than the UL. The unfortunate result is that there is
minimal motivation for policy makers to implement the
relatively simple steps that could correct this nutrient
deficiency.
Because of the convincing evidence for benefit and the strong
evidence of safety, we urge those who have the ability to
support public health - the media, vitamin manufacturers, and
policy makers - to undertake new initiatives that will have a
realistic chance of making a difference in terms of vitamin D
nutrition. We call for international agencies such as the
Food and Nutrition Board and the European Commission's Health
and Consumer Protection Directorate-General to reassess as a
matter of high priority their dietary recommendations for
vitamin D, because the formal nationwide advice from health
agencies needs to be changed."
--
Matti Narkia
The study
Hypponen E, Power C.
Hypovitaminosis D in British adults at age 45 y: nationwide cohort
study of dietary and lifestyle predictors.
Am J Clin Nutr. 2007 Mar;85(3):860-8.
PMID: 17344510 [PubMed - in process]
< http :// www .ajcn.org/cgi/content/abstract/85/3/860>
published in the latest issue of AJCN investigated vitamin D status
(serum calcidiol a.k.a (25(OH)D concentrations) of British adults at
age 45 and found that the prevalence of hypovitaminosis D
was alarmingly high during the winter and spring. Below the abstract
of the study:
"BACKGROUND: Increased awareness of the importance of vitamin
D to health has led to concerns about the prevalence of
hypovitaminosis D in many parts of the world. OBJECTIVES: We
aimed to determine the prevalence of hypovitaminosis D in the
white British population and to evaluate the influence of key
dietary and lifestyle risk factors. DESIGN: We measured 25-
hydroxyvitamin D [25(OH)D] in 7437 whites from the 1958
British birth cohort when they were 45 y old. RESULTS: The
prevalence of hypovitaminosis D was highest during the winter
and spring, when 25(OH)D concentrations <25, <40, and <75
nmol/L were found in 15.5%, 46.6%, and 87.1% of participants,
respectively; the proportions were 3.2%, 15.4%, and 60.9%,
respectively, during the summer and fall. Men had higher
25(OH)D concentrations, on average, than did women during the
summer and fall but not during the winter and spring (P 0.006, likelihood ratio test for interaction). 25(OH)D
concentrations were significantly higher in participants who
used vitamin D supplements or oily fish than in those who did
not (P < 0.0001 for both) but were not significantly higher
in participants who consumed vitamin D-fortified margarine
than in those who did not (P = 0.10). 25(OH)D concentrations
<40 nmol/L were twice as likely in the obese as in the
nonobese and in Scottish participants as in those from other
parts of Great Britain (ie, England and Wales) (P < 0.0001
for both). CONCLUSION: Prevalence of hypovitaminosis D in the
general population was alarmingly high during the winter and
spring, which warrants action at a population level rather
than at a risk group level."
In the same issue of AJCN there is a Dutch vitamin D study
van Dam RM, Snijder MB, Dekker JM, Stehouwer CD, Bouter LM, Heine RJ,
Lips P.
Potentially modifiable determinants of vitamin D status in an older
population in the Netherlands: the Hoorn Study.
Am J Clin Nutr. 2007 Mar;85(3):755-761.
PMID: 17344497 [PubMed - as supplied by publisher]
< http :// www .ajcn.org/cgi/content/abstract/85/3/755>,
which found that low vitamin D status among elderly people is very
common also in Holland. Here's its abstract:
"BACKGROUND: Inadequate vitamin D status is common in many
populations around the world. OBJECTIVE: The aim was to
evaluate potentially modifiable determinants of vitamin D
status in an older population. DESIGN: This was a cross-
sectional study from a population-based cohort including 538
white Dutch men and women aged 60-87 y. Vitamin D status was
assessed by plasma 25-hydroxyvitamin D [25(OH)D]
concentrations. RESULTS: In the winter period, 51% of the
subjects had 25(OH)D concentrations <50.0 nmol/L. Greater
body fatness and less time spent on outdoor physical activity
were associated with worse vitamin D status. Regular use of
vitamin D-fortified margarine products [odds ratio (OR) in a
comparison of intake of >/ g/d with none: 0.41; 95% CI:
0.20, 0.86; P for trend < 0.001], fatty fish (OR for servings
of >/=2/mo versus none: 0.41; 95% CI: 0.16, 1.04; P for trend
= 0.01), and vitamin D-containing supplements (OR for >/= 1/d
versus none: 0.33; 95% CI: 0.17, 0.63; P for trend < 0.001)
were inversely associated with vitamin D inadequacy [25(OH)D
<50.0 nmol/L]. We estimated that combined use of margarine
products (20 g/d), fatty fish (100 g/wk), and vitamin D
supplements (>/=1/d) was associated with a 16.8 nmol/L higher
25(OH)D concentration than was the use of none of these.
However, none of the participants reached these intakes for
all 3 factors. CONCLUSION: Because few foods are vitamin D-
fortified and the amounts of vitamin D in supplements are
low, it is difficult to achieve adequate vitamin D status
through increasing intakes in the Netherlands and in
countries with similar policies."
The editorial of the same issue,
Vieth R, Bischoff-Ferrari H, Boucher BJ, Dawson-Hughes B, Garland CF,
Heaney RP, Holick MF, Hollis BW, Lamberg-Allardt C, McGrath JJ, Norman
AW, Scragg R, Whiting SJ, Willett WC, Zittermann A.
The urgent need to recommend an intake of vitamin D that is effective.
Am J Clin Nutr. 2007 Mar;85(3):649-50.
PMID: 17344484 [PubMed - in process]
< http :// www .ajcn.org/cgi/content/full/85/3/649>,
whose list of authors is packed with the most famous and appreciated
vitamin D researchers and also includes Harvard's Walter C. Willett,
comments the study by Hyppönen and Power, states the urgent need to
raise vitamin D recommendations, and appeals to the authorities and
other policy makers, media, vitamin manufacturers, etc., to work for
this goal to get that done as soon as possible. Below a couple of
excerpts from this article:
"The report by Hyppönen and Power in this issue of the
Journal (1) highlights a frustrating and regrettable
situation for nutrition researchers. In the early 1970s, the
same serum 25-hydroxyvitamin D [25(OH)D] concentrations
reported by Hyppönen and Power were thought to be indicative
of "healthy" white adults in the United Kingdom (2). However,
during those early years after the discovery of 25(OH)D, the
adequacy of its serum concentration was based simply on
whether the concentration was enough to prevent osteomalacia
or rickets. Three decades later, we know that 25(OH)D
concentrations relate to many other aspects of health,
including fracture risk, bone density, colon cancer, and even
tooth attachment (3); we also know that much higher
concentrations of 25(OH)D are needed to prevent adverse
outcomes. Indeed, in the 1958 British birth cohort, lower
25(OH)D is associated with a higher percentage of hemoglobin
A1C (a measure of long-term glucose concentration), which
further emphasizes the need to maintain optimal 25(OH)D
concentrations (4).
[...]
It is important for major journals such as the AJCN to
publish evidence of a widespread nutrient deficiency.
Regrettably, we are now stuck in a revolving cycle of
publications that are documenting the same vitamin D
inadequacy (1-3, 5, 7-9, 13-17). This phenomenon has been
referred to as "circular epidemiology" (18), and, for vitamin
D, the phenomenon will continue for as long as the levels of
vitamin D fortification and supplementation and the practical
advice offered to the public remain essentially the same as
they were in the era before we knew that 25(OH)D even
existed. As scientists, the purpose of our work is to improve
the health of the public. We know the realities of serum
25(OH)D concentrations in populations around the world, and
we have come to the conclusion that public health will
benefit from improved vitamin D nutritional status. We know
the intakes of vitamin D needed to bring about desirable
25(OH)D concentrations, so why is the science not making a
difference to public health? A major reason is that there is
little public pressure on policy makers to support efforts to
update recommendations about nutrition. Public pressure is
generally rooted in the media, but we do not think that the
public media present the vitamin D story in a complete and
accurate manner. Reports about vitamin D inadequacies are
presented straightforwardly, but, when it comes to discussing
the intake of vitamin D needed to correct the situation,
outdated official recommendations for vitamin D are
propagated by the public media. This probably occurs because
of restrictive editorial policies driven by concern about
possible litigation if media were to advise a "toxic" intake
greater than the UL. The unfortunate result is that there is
minimal motivation for policy makers to implement the
relatively simple steps that could correct this nutrient
deficiency.
Because of the convincing evidence for benefit and the strong
evidence of safety, we urge those who have the ability to
support public health - the media, vitamin manufacturers, and
policy makers - to undertake new initiatives that will have a
realistic chance of making a difference in terms of vitamin D
nutrition. We call for international agencies such as the
Food and Nutrition Board and the European Commission's Health
and Consumer Protection Directorate-General to reassess as a
matter of high priority their dietary recommendations for
vitamin D, because the formal nationwide advice from health
agencies needs to be changed."
--
Matti Narkia
Re: Prevalence of hypovitaminosis D in UK and Holland alarmingly high in winter, urgent need to reco
On Sun, 11 Mar 2007 12:55:58 +0200, Matti Narkia <mna@mbnet.fi> wrote:
>The study
>
>Hypponen E, Power C.
>Hypovitaminosis D in British adults at age 45 y: nationwide cohort
>study of dietary and lifestyle predictors.
>Am J Clin Nutr. 2007 Mar;85(3):860-8.
>PMID: 17344510 [PubMed - in process]
>< http :// www .ajcn.org/cgi/content/abstract/85/3/860>
>
>published in the latest issue of AJCN investigated vitamin D status
>(serum calcidiol a.k.a (25(OH)D concentrations) of British adults at
>age 45 and found that the prevalence of hypovitaminosis D
>was alarmingly high during the winter and spring.
[snip]
>The editorial of the same issue,
>
>Vieth R, Bischoff-Ferrari H, Boucher BJ, Dawson-Hughes B, Garland CF,
>Heaney RP, Holick MF, Hollis BW, Lamberg-Allardt C, McGrath JJ, Norman
>AW, Scragg R, Whiting SJ, Willett WC, Zittermann A.
>The urgent need to recommend an intake of vitamin D that is effective.
>Am J Clin Nutr. 2007 Mar;85(3):649-50.
>PMID: 17344484 [PubMed - in process]
>< http :// www .ajcn.org/cgi/content/full/85/3/649>,
>
>whose list of authors is packed with the most famous and appreciated
>vitamin D researchers and also includes Harvard's Walter C. Willett,
>comments the study by Hyppönen and Power, states the urgent need to
>raise vitamin D recommendations, and appeals to the authorities and
>other policy makers, media, vitamin manufacturers, etc., to work for
>this goal to get that done as soon as possible.
A related news article:
Vitamin D level reassessment high priority, say experts
< http :// www .nutraingredients-usa,com /news/ng.asp?nt831-vitamin-d-supplements-tolerable-upper-intake-level>
"3/9/2007 - International agencies should reassess as a
matter of high priority dietary recommendations for vitamin
D, experts have said, because current advice is outdated and
puts the public at risk of deficiency.
Fifteen experts from universities, research institutes, and
university hospitals around the world, led by Reinhold Vieth
from Toronto's Mount Sinai Hospital wrote in the American
Journal of Clinical Nutrition: "We call for international
agencies such as the Food and Nutrition Board and the
European Commission's Health and Consumer Protection
Directorate-General to reassess as a matter of high priority
their dietary recommendations for vitamin D, because the
formal nationwide advice from health agencies needs to be
changed."
"The balance of the evidence leads to the conclusion that the
public health is best served by a recommendation of higher
daily intakes of vitamin D. Relatively simple and low-cost
changes, such as increased food fortification or increasing
the amount of vitamin D in vitamin supplement products, may
very well bring about rapid and important reductions in the
morbidity associated with low vitamin D status," they said.
The editorial was written in response to a UK-based study,
published in the same journal, which reported that there
exists an alarmingly high prevalence of hypovitaminosis D in
the general population during the winter and spring.
Vitamin D refers to two biologically inactive precursors -
D3, also known as cholecalciferol, and D2, also known as
ergocalciferol. The former, produced in the skin on exposure
to UVB radiation (290 to 320 nm), is said to be more
bioactive. The latter is derived from plants and only enters
the body via the diet.
Both D3 and D2 precursors are hydroxylated in the liver and
kidneys to form 25- hydroxyvitamin D (25(OH)D), the non-
active 'storage' form, and 1,25-dihydroxyvitamin D (1,25(OH)
2D), the biologically active form that is tightly controlled
by the body.
The study, by Elina Hyppönen and Chris Power from the
Institute of Child Health in London, measured the level of
25(OH)D in 7437 whites from the 1958 British birth cohort
when the subjects had reached the age of 45.
Hyppönen and Power report that prevalence of low vitamin D
levels was highest during the winter and spring, when 46.6
per cent of participants had 25(OH)D concentrations of less
than 40 nanomoles per litre while this fell to 15.4 per cent
during the summer and autumn.
Vitamin D is produced in the skin on exposure to UVB
radiation and can also be consumed in small amounts from the
diet. However, recent studies have shown that sunshine levels
in some northern countries are so weak during the winter
months that the body makes no vitamin D at all, leading some
to estimate that over half of the population in such
countries have insufficient or deficient levels of the
vitamin.
"Prevalence of hypovitaminosis D in the general population
was alarmingly high during the winter and spring, which
warrants action at a population level rather than at a risk
group level," concluded the researchers.
Vieth and his collaborators said the study was yet another
publication in a series that document low vitamin D levels,
and this will continue while recommended levels of vitamin D
intake remain outdated.
"Because of the convincing evidence for benefit and the
strong evidence of safety, we urge those who have the ability
to support public health-the media, vitamin manufacturers,
and policy makers-to undertake new initiatives that will have
a realistic chance of making a difference in terms of vitamin
D nutrition," wrote Vieth and collaborators.
A recent review of the science reported that the tolerable
upper intake level for oral vitamin D3 should be increased
five-fold, from the current tolerable upper intake level (UL)
in Europe and the US of 2000 International Units (IU),
equivalent to 50 micrograms per day, to 10,000 IU (250
micrograms per day).
Source: The American Journal of Clinical Nutrition
March 2007, Volume 85, Number 3, Pages 860-868
"Hypovitaminosis D in British adults at age 45 y: nationwide
cohort study of dietary and lifestyle predictors"
Authors: E. Hyppönen and C. Power
Editorial: The American Journal of Clinical Nutrition
March 2007, Volume 85, Number 3, Pages 649-650
"The urgent need to recommend an intake of vitamin D that is
effective"
Authors: R. Vieth, H. Bischoff-Ferrari, B.J. Boucher, B.
Dawson- Hughes, C.F. Garland, R.P. Heaney, M.F. Holick, B.W.
Hollis, C. Lamberg-Allardt, J.J. McGrath, A.W. Norman, R.
Scragg, S.J. Whiting, W.C. Willett, and A. Zittermann"
--
Matti Narkia
On Sun, 11 Mar 2007 12:55:58 +0200, Matti Narkia <mna@mbnet.fi> wrote:
>The study
>
>Hypponen E, Power C.
>Hypovitaminosis D in British adults at age 45 y: nationwide cohort
>study of dietary and lifestyle predictors.
>Am J Clin Nutr. 2007 Mar;85(3):860-8.
>PMID: 17344510 [PubMed - in process]
>< http :// www .ajcn.org/cgi/content/abstract/85/3/860>
>
>published in the latest issue of AJCN investigated vitamin D status
>(serum calcidiol a.k.a (25(OH)D concentrations) of British adults at
>age 45 and found that the prevalence of hypovitaminosis D
>was alarmingly high during the winter and spring.
[snip]
>The editorial of the same issue,
>
>Vieth R, Bischoff-Ferrari H, Boucher BJ, Dawson-Hughes B, Garland CF,
>Heaney RP, Holick MF, Hollis BW, Lamberg-Allardt C, McGrath JJ, Norman
>AW, Scragg R, Whiting SJ, Willett WC, Zittermann A.
>The urgent need to recommend an intake of vitamin D that is effective.
>Am J Clin Nutr. 2007 Mar;85(3):649-50.
>PMID: 17344484 [PubMed - in process]
>< http :// www .ajcn.org/cgi/content/full/85/3/649>,
>
>whose list of authors is packed with the most famous and appreciated
>vitamin D researchers and also includes Harvard's Walter C. Willett,
>comments the study by Hyppönen and Power, states the urgent need to
>raise vitamin D recommendations, and appeals to the authorities and
>other policy makers, media, vitamin manufacturers, etc., to work for
>this goal to get that done as soon as possible.
A related news article:
Vitamin D level reassessment high priority, say experts
< http :// www .nutraingredients-usa,com /news/ng.asp?nt831-vitamin-d-supplements-tolerable-upper-intake-level>
"3/9/2007 - International agencies should reassess as a
matter of high priority dietary recommendations for vitamin
D, experts have said, because current advice is outdated and
puts the public at risk of deficiency.
Fifteen experts from universities, research institutes, and
university hospitals around the world, led by Reinhold Vieth
from Toronto's Mount Sinai Hospital wrote in the American
Journal of Clinical Nutrition: "We call for international
agencies such as the Food and Nutrition Board and the
European Commission's Health and Consumer Protection
Directorate-General to reassess as a matter of high priority
their dietary recommendations for vitamin D, because the
formal nationwide advice from health agencies needs to be
changed."
"The balance of the evidence leads to the conclusion that the
public health is best served by a recommendation of higher
daily intakes of vitamin D. Relatively simple and low-cost
changes, such as increased food fortification or increasing
the amount of vitamin D in vitamin supplement products, may
very well bring about rapid and important reductions in the
morbidity associated with low vitamin D status," they said.
The editorial was written in response to a UK-based study,
published in the same journal, which reported that there
exists an alarmingly high prevalence of hypovitaminosis D in
the general population during the winter and spring.
Vitamin D refers to two biologically inactive precursors -
D3, also known as cholecalciferol, and D2, also known as
ergocalciferol. The former, produced in the skin on exposure
to UVB radiation (290 to 320 nm), is said to be more
bioactive. The latter is derived from plants and only enters
the body via the diet.
Both D3 and D2 precursors are hydroxylated in the liver and
kidneys to form 25- hydroxyvitamin D (25(OH)D), the non-
active 'storage' form, and 1,25-dihydroxyvitamin D (1,25(OH)
2D), the biologically active form that is tightly controlled
by the body.
The study, by Elina Hyppönen and Chris Power from the
Institute of Child Health in London, measured the level of
25(OH)D in 7437 whites from the 1958 British birth cohort
when the subjects had reached the age of 45.
Hyppönen and Power report that prevalence of low vitamin D
levels was highest during the winter and spring, when 46.6
per cent of participants had 25(OH)D concentrations of less
than 40 nanomoles per litre while this fell to 15.4 per cent
during the summer and autumn.
Vitamin D is produced in the skin on exposure to UVB
radiation and can also be consumed in small amounts from the
diet. However, recent studies have shown that sunshine levels
in some northern countries are so weak during the winter
months that the body makes no vitamin D at all, leading some
to estimate that over half of the population in such
countries have insufficient or deficient levels of the
vitamin.
"Prevalence of hypovitaminosis D in the general population
was alarmingly high during the winter and spring, which
warrants action at a population level rather than at a risk
group level," concluded the researchers.
Vieth and his collaborators said the study was yet another
publication in a series that document low vitamin D levels,
and this will continue while recommended levels of vitamin D
intake remain outdated.
"Because of the convincing evidence for benefit and the
strong evidence of safety, we urge those who have the ability
to support public health-the media, vitamin manufacturers,
and policy makers-to undertake new initiatives that will have
a realistic chance of making a difference in terms of vitamin
D nutrition," wrote Vieth and collaborators.
A recent review of the science reported that the tolerable
upper intake level for oral vitamin D3 should be increased
five-fold, from the current tolerable upper intake level (UL)
in Europe and the US of 2000 International Units (IU),
equivalent to 50 micrograms per day, to 10,000 IU (250
micrograms per day).
Source: The American Journal of Clinical Nutrition
March 2007, Volume 85, Number 3, Pages 860-868
"Hypovitaminosis D in British adults at age 45 y: nationwide
cohort study of dietary and lifestyle predictors"
Authors: E. Hyppönen and C. Power
Editorial: The American Journal of Clinical Nutrition
March 2007, Volume 85, Number 3, Pages 649-650
"The urgent need to recommend an intake of vitamin D that is
effective"
Authors: R. Vieth, H. Bischoff-Ferrari, B.J. Boucher, B.
Dawson- Hughes, C.F. Garland, R.P. Heaney, M.F. Holick, B.W.
Hollis, C. Lamberg-Allardt, J.J. McGrath, A.W. Norman, R.
Scragg, S.J. Whiting, W.C. Willett, and A. Zittermann"
--
Matti Narkia
