Should a teenage girl take a Vitamin D supplement?

Yorky

This is an ongoing debate amongst the parents concerned regarding the absorption of calcium for bone density.

The rationale of one parent is that due to lack of sunlight in Ireland (especially the northern half) it is necessary to take a supplement.

The other parent maintains that sunlight levels are adequate and the naturally occuring vitamin D in a balanced diet, albeit only in small amounts, is also adequate.

The supplements being taken at the moment are these http://www.healthspan.co.uk/bone-health/vitamin-d-tablets-400iu-the/ProductDetail-p414-c158.aspx

Can anyone definitively answer this question and provide links to supporting evidence?

Thanks in advance.

Sapsorrow

Yorky wrote: »

This is an ongoing debate amongst the parents concerned regarding the absorption of calcium for bone density.

The rationale of one parent is that due to lack of sunlight in Ireland (especially the northern half) it is necessary to take a supplement.

The other parent maintains that sunlight levels are adequate and the naturally occuring vitamin D in a balanced diet, albeit only in small amounts, is also adequate.

The supplements being taken at the moment are these http://www.healthspan.co.uk/bone-health/vitamin-d-tablets-400iu-the/ProductDetail-p414-c158.aspx

Can anyone definitively answer this question and provide links to supporting evidence?

Thanks in advance.

YES YES YES and YES! There is NO debate on this one (who ever said there was ) it's a fact that we don't get enough sunlight from November through March in Ireland fas the UVB rays cannot penetrate the atmosphere sufficiently due to our latitude, the only exception is someone who spends a LOT of time on sun holidays, not wearing sunscreen and sunbathing, as the stores they will develop abroad will offer them protection for some of the autumn and winter.
Also a calcium supplement is equally important, neither are toxic in anyway, the only issue is that calcium can inhibit Iron absorption and so should be taken at a time in the day away from the meal suppling the most iron (probably dinner) if the girl is a vegetarian.
The nutrition dept in my college does loads of work on vitamin D and bone health as well as being partners in all the major Irish food consumption surveys over the last decade, so I've seen all the stats from the north south food consumption survey and the childrens/teens surveys in class many times and most children and teenagers in Ireland aren't getting anything near enough calcium or vitamin D. From the teens survey: 23% of boys and 42% of girls don't meet the minimum requirement for calcium, the mean daily intake for vitamin D is 2.7 micrograms and 22% get less than 1 microgram a day. Very disturbing really. After childhood obesity it's easily Irelands primary nutrition+child related public health problem.
I'm too busy to go looking up papers, anyone interested should be able to do that for themselves, I'd reccomend looking for the results of the children and teens Irish food cunsumption surveys though to put it all into perspective. Like I said already though it's hardly up for debate.

EDIT: to put the mean Irish vitamin D intake into perspective I should have mentioned the requirement is 5 micrograms a day for teenagers and adults.

El_Dangeroso

Totally agree with Khrystyna. At this latitude we get a pathetic amount of vitamin D. Deficiency is widespread across all age groups:

Hill TR, O'Brien MM, Lamberg-Allardt C, Jakobsen J, Kiely M, Flynn A, et al. Vitamin D status of 51-75-year-old Irish women: its determinants and impact on biochemical indices of bone turnover. Public Health Nutrition. 2006 Apr;9(2):225-33.

McCarthy D, Collins A, O'Brien M, Lamberg-Allardt C, Jakobsen J, Charzewska J, et al. Vitamin D intake and status in Irish elderly women and adolescent girls. Irish Journal of Medical Science. 2006 Apr-Jun;175(2):14-20.

There has been a new study published in the American journal of clinical nutrition where they gave 1,200IU(15micrograms) a day to Japanese school children. There was a drastic reduction in incidence of asthma and type A influenza in the supplemented group compared to the placebo, no adverse effects of supplementation were observed. This is three times the RDA for an adult and this was in sunny Japan so you can see how woefully inadequate the RDA for Irish people is at the moment.

I recommend 5,000IU a day of D3(the type our body creates from sunshine) for adults on days when they don't get 1 hour mid-day exposure on their bare arms in the summer sun. The only reason not to supplement is if you have sarcoidosis or hyperparathyroidism.

Vitamin D isn't strictly vitamin, it's technically a hormone. So you can imagine the implications of not having sufficient supply of a hormone in your body. Bone maintenance is actually probably one of it's least important functions. So far we've discovered hundred's of genes whose expression is under the direct control of vitamin D. I've even heard it can prevent the male pattern baldness gene from expressing! Though there haven't been any experiments testing that yet

Iristxo

I concur with the replies above but

khrystyna100 wrote: »

the only issue is that calcium can inhibit Iron absorption and so should be taken at a time in the day away from the meal suppling the most iron (probably dinner) if the girl is a vegetarian.

I thought this had been already disproved several times? Proof is some countries who happen to eat a lot of diary (Mexico for example) do not have a higher incidence of anemia

Sapsorrow

Iristxo wrote: »

I thought this had been already disproved several times? Proof is some countries who happen to eat a lot of diary (Mexico for example) do not have a higher incidence of anemia

Epidemiology can't actually prove anything it can only form the basis of a hypothesis. I doubt there are many vegetarians in south America either! There could be any number of other confounding factors that need to be taken into consideration anyway and I was more referring to the use of supplements that dietary intake, as most vegetarian female tennagers should really be taking an iron supplement unless they have a phenomenally good diet.
From the Irish teen survey: 74% of ALL (not just vegetarian) teenage girls fail to meet the minimum requirement for Iron despite 16% of their energy needs being met by meat and meat products,18% from breads and cereals (which should contribute a lot through voluntary fortification) and 11% being met from milk, cheese and yoghurt.

Iristxo

khrystyna100 wrote: »

Epidemiology can't actually prove anything it can only form the basis of a hypothesis. I doubt there are many vegetarians in south America either! There could be any number of other confounding factors that need to be taken into consideration anyway and I was more referring to the use of supplements that dietary intake, as most vegetarian female tennagers should really be taking an iron supplement unless they have a phenomenally good diet.
From the Irish teen survey: 74% of ALL (not just vegetarian) teenage girls fail to meet the minimum requirement for Iron despite 16% of their energy needs being met by meat and meat products,18% from breads and cereals (which should contribute a lot through voluntary fortification) and 11% being met from milk, cheese and yoghurt.

I'll see if I manage to dig out the studies that proved that too much calcium does not hinder iron absorption, I'll report back if I find the links

EileenG

Just to add that vitamin D occurs naturally in high fat foods like egg and butter and oily fish. A typical teenager will often avoid these foods in an effort not to put on weight, and due to the stuff that's still being taught in home ec classes in school.