Scientific studies have consistently linked low
vitamin D to cancer, heart disease, diabetes, multiple sclerosis, and many
other major and minor conditions. The amount of vitamin D required to protect
against these conditions is much greater than that required for protection
against rickets and osteomalacia. Growing urbanization, reduced physical
activity and low exposure to sunlight are believed to contribute to a spurt of
Vitamin D deficiency diseases as evidenced from low circulating vitamin D
levels. Vitamin D is now considered
more as a pro-hormone, than a vitamin. Incidentally, vitamin D can be
synthesized in the body in adequate amounts just by exposing yourself to bright
sunlight for 5 minutes a day.
the UK, there has been an evidence of a resurgence of vitamin D deficiency in
children. The National Diet and Nutrition
Survey (NDNS) for young people (4-18 years old) in Great Britain reports
that approximately 8 percent of children have less than 25 nmol/L of 25-hydroxy
Vitamin D (25[OH]D) levels (or
the storage form of vitamin D) and are thus considered vitamin D
deficient. They also report that this deficiency is evident in most population
age groups including older children and young adults.
Deficiency of vitamin D is seen to occur
either due to dietary factors or non-dietary factors.
of vitamin D rich food
vitamin D supplementation
vitamin D levels due to obesity
Vitamin D is mainly obtained from foods
that are rich sources of this vitamin, for example, fatty fish such as
salmon, tuna, and mackerel, fish liver oils, beef liver, cheese, and egg yolks. Other sources include dietary
supplements, fortified foods such as infant foods, milk, or breakfast cereals
and sunlight exposure.
The Recommended dietary allowance
developed by the Food and Nutrition board for children, United States is as
There are no UK Reference Nutrient Intake
values for vitamin D or government supplementation recommendations for older
children.Recent UK government
published guidelines recommend vitamin D supplementation at a level of
7mcg/day, only to children younger than 5 years of age.
The 2007 Scientific Advisory Committee on
Nutrition report recommends that individuals at risk of inadequate sunshine
exposure should receive supplementation of up to 10mcg/day. Additionally the UK
government recommendations suggest regular, short periods of sunlight exposure
without sunscreen during the summer months. They also highlight the risk of skin
cancer and recommend the use of sunscreen (with a high UVB factor) for the
majority of time spent outside.
In view of the paucity of data in the UK
and indeed worldwide on the prevalence, predictors and associations of vitamin
D insufficiency (VDI) astudy was
conducted to evaluate the prevalence and predictors of vitamin D insufficiency
VDI in children in Great Britain. A
nationally representative cross-sectional study survey of children (1102) aged
4-18 years (999 white, 570 male) living in private households (January
1997-1998) was conducted. Information about dietary habits, physical activity,
socio-demographics was taken and blood samples were collected.
The following variables, proposed as the
possible predictors or causes for vitamin D deficiency amongst the children
Age, gender and ethnicity
Whether on income support
Blood levels taken between December and May
Amount spent per week in sports involving outdoor exercise or play
Amount spent a day per week watching TV
Vitamin D dietary intake and supplemental Vitamin D intake
Body Mass Index (BMI [kg/m2
For the purposes of this study, Vitamin D
status was defined as insufficient when 25(OH) D levels were less than 50
nmol/L). Vitamin D levels were available for 1102 samples.
Following results were derived:
.35.1 percent of children aged between 4
to 18 years were vitamin D insufficient
·Plasma vitamin D levels decreased
progressively with age in both sexes.
·There was no difference in the deficiency
noted between girls and boys.
·There were marked seasonal differences
found for vitamin D levels in children.
whose families were on income support had significantly lower vitamin D levels.
spent more time doing outdoor exercise (at least half an hour/day/week) and
less time watching TV per day (less than 2.5 hours) had higher vitamin D
dietary intake had no influence on vitamin D status. However, children who were
taking vitamin D supplements had higher overall vitamin D levels.
and obese children had lower vitamin D levels.
The results from this study confirm the
high prevalence of VDI amongst UK children. The findings also clearly show that
in children, there is no significant gender difference, but there is an increasing
risk of VDI in older age groups. The researchers state that older children
probably are lesser exposed to sunlight due to fewer incentives and
opportunities to play outdoors. Supplements may be beneficial for older
children, especially during the winter months given the higher risk of VDI
Additionally, children whose families
were in receipt of income support had more than twice the odds of those not on
income supports; hence potentially government initiatives to tackle social
inequalities may have an impact on vitamin D status.
Marked seasonal differences found in the
study also stress that preventative strategies may be more necessary during the
winter and spring months when vitamin D levels are at their lowest.
Children, who exercised outdoors for less
than half an hour/day/week, were overweight and watched more than 2.5
hours/day/week of TV were at a greater risk of being deficient. These are
potentially modifiable risk factors and therefore need to be seriously taken
care of by the parents.
study implies that initiatives to increase safe sunlight exposure by increasing
opportunities and encouraging more outdoor activities, particularly in the
summer months, may have an impact on vitamin D status. This also suggests that
guidelines encouraging safe sunlight exposure and how this message is portrayed
may need to be revised.
It is interesting that dietary intake was not associated with vitamin D status,
and therefore the study states the efforts in this area, would not be as effective
as other suggested methods.
of vitamin D insufficiency in childhood may potentially prevent longer term
chronic disease with presentation in adulthood and this is an area, which is
under research at present. Unfavorable cardio metabolic risk factors in adults,
hyperglycemia and the metabolic syndrome, type-1 diabetes, multiple sclerosis,
malignancy and schizophrenia have all been implicated as potential consequences
of early vitamin D insufficiency.
Experts suggest the need for devising clearer
guidelines for vitamin D deficiency prevention coupled with increased awareness
(especially in older children and at risk groups). Altogether the research
undertaken clearly gets the clinicians to understand the severity of the
problem and further guide their clinical decisions in order to establish
D requirements for children: The Recent Indian Recommendation:
As the body largely depends on vitamin D synthesis
by the skin on sun-exposure, its dietary requirement is usually very small in
the Indian context. It is important to note that even in India, the young
growing children and adults, particularly in the urban areas, are physically
less active and are not being exposed outdoors. This has eventually reduced the
chances of vitamin D formation. This problem is being increasingly felt as more
and more studies are reporting reduced circulating levels of 25 HCC in children
of school age and also in some adults.
The Expert group of Indian Council of Medical
Research feels that increasing the RDI (recommended dietary intake) is not the
solution. Rather, ensuring adequate exposure to sunlight is the way out.
Outdoor physical activity is a way of achieving both adequate vitamin D status
and controlling overweight and obesity in the population. However, under
situations of minimal exposure to sunlight, a recommendation of a daily
supplement of 400 IU (10 μg) is suggested.
Prevalence and Predictors
of Vitamin D Insufficiency in Children: A Great Britain Population Based Study;
Michael Absoud et al; Plos One 2011.
Nutrient requirements and recommended dietary allowances for Indians
A report of the expert group of the Indian council of medical research,
2009. National Institute of Nutrition. Indian Council of Medical Research,