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Baby sitting in sun

We make vitamin D in our own bodies when rays from the sun hit our skin. In strong sunlight our skin is able to manufacture all the vitamin D it needs for the day in a matter of minutes. And because it’s fat soluble, it can be stored in the body, unlike lots of vitamins

Do we get enough vitamin D from the sun in the UK?

Unfortunately, if you live in the UK (and other countries in the northern latitudes, e.g. Scandinavia), the sunlight available between the months of October and March is too weak to enable us to manufacture sufficient amounts of vitamin D.

It used to be thought that it was possible to make enough vitamin D for the body to store and use throughout the winter. This may have been true in the recent past, when children and adults spent a lot more time outside and active in the sunshine. However, our modern lifestyle doesn’t allow us to make as much vitamin D as in the past because:

  • Children spend a lot of time inside and the sunlight that comes through glass doesn’t activate vitamin D production
  • Lots of children are covered up when outside, whether for cultural reasons, or to protect them from sunburn
  • Darker skin takes longer to make vitamin D, with some research suggesting that it takes 3-10 times longer to achieve the same vitamin D production as a light-skinned person
  • Very light-skinned people tend to cover up in the sun with clothing or sunscreen to prevent burning, skin cancer or premature ageing

Can we get enough vitamin D from a balanced diet?

It is not possible to get all the vitamin D we need from the food we eat. So doctors in the UK have seen an increase in cases of rickets in children, which is a sign of extreme vitamin D deficiency. Many groups such as the Royal College of Paediatrics are so concerned that they have recommended that all children under five, as well as pregnant and breastfeeding mums, take a daily vitamin D supplement.

A German study reported that we get less than 10% of our vitamin D requirement from food.

Which foods contain vitamin D?

Vitamin D is found naturally in oily fish and eggs. It has also been added to some fortified foods such as breakfast cereals and margarines. In the UK, milk is not a good source of vitamin D as it is not fortified.

Why does my baby need it?

Your baby needs vitamin D in order to absorb calcium, which is vital for growing strong bones and healthy teeth. Calcium is needed in the bloodstream for a variety of functions and without enough vitamin D, a child’s body will prioritise this over calcium for their growing bones. This results in the tell-tale bent bones of rickets.

Vitamin D is much more than a bone builder

Vitamin D controls lots of vital body chemical reactions. Many scientific papers have reported that vitamin D deficiency found in northern countries such as Scandinavia, Canada and the UK is associated with increased rates of autoimmune conditions such as Type 1 diabetes, multiple sclerosis, thyroid disorders and several cancers that are much more prevalent in these countries.

So how can I make sure my baby gets enough?

You can pass on vitamin D to your baby during pregnancy and when you are breastfeeding them. In order to give them enough you need to take a vitamin D supplement yourself so it gets into your bloodstream and is available for your baby either across the placenta or in your breast milk.

Vitamin D supplements for pregnant women

The NHS advises that all pregnant women take 10µg (that’s micrograms, not milligrams) of vitamin D throughout their pregnancy. If you are planning to get pregnant, start taking vitamin D supplements straight away.

Supplements for breastfeeding mums

You should continue to take your vitamin D supplement while you are breastfeeding – it’s also a good idea even if you are not breastfeeding. There would be no harm in continuing to take it as you are replacing any vitamin D you have lost in the pregnancy. In addition, if you live in the UK you will probably not be producing enough vitamin D in your skin either, so a supplement is a good idea.

Supplements for babies

  • Babies who are breastfed by a mum who took vitamin D throughout her whole pregnancy, and who is still taking a vitamin D supplement, or babies being fed formula milk with a contained vitamin D supplement, may not need to have vitamin D supplements until they are six months old
  • However, some babies, (e.g. those whose mum didn’t take vitamin D throughout their pregnancy), will need supplements from four weeks. For more information about vitamin supplements for your baby, speak to their doctor
  • Babies do not need vitamin D supplements if they are drinking (not merely being offered) more than 500ml of formula milk each day because formula milk is fortified with vitamin D. Discuss vitamins with your baby’s doctor when she is drinking less than this amount a day
  • If you are more at risk of vitamin D deficiency yourself – that is, if you are darker skinned, always wear clothing that completely covers you or are housebound – you will have been less able to pass on vitamin D to your baby during pregnancy and breastfeeding, so speak to your baby’s GP about what supplements your baby needs and when to start
  • Again, if you are more at risk of vitamin D deficiency yourself, ask your GP or obstetrician to check your vitamin D status as well. This can be done with a simple blood test

Is it possible to have too much vitamin D?

Vitamin D is stored in the body so with continual high levels of supplementation it could be toxic, but you cannot get toxic amounts from the sun alone.

Keep an eye on the recommendations on vitamin D supplements, as the RDA has gone up since the flawed recommendations from the 1950s. Also, speak to your doctor about your own family circumstances and discuss getting a blood test for you or your child if you are really concerned about vitamin D deficiency.

I thought breast milk had everything my baby needed?

When we lived more traditional lives outside with lots of sun exposure, living at lower latitudes and wore fewer clothes, human breast milk would have contained good levels of vitamin D. These days, with our modern lives, breast milk alone does not contain all the vitamin D your baby needs.

Breast milk is still the best food you can give your baby and you can make the milk contain sufficient vitamin D as well if you take a supplement throughout pregnancy and whilst breastfeeding.

In modern studies, breast milk from mums not taking vitamin D supplements contains 15-50 international units per litre (IU/L) of vitamin D, with an average of 25 IU/L (0.62µg). This is not sufficient to meet the requirements of a baby.

Again, we need to look at our modern lifestyle to discover why breast milk has lower levels of vitamin D than we expect. Most people, including breastfeeding women, no longer live outdoors, semi-naked, without houses, offices, cars or pollution. Today, many people spend less than an hour outside per day – they may walk straight to their car, drive to work and walk straight into an office for all their daylight hours.  Children don’t play in the street, they play inside and may then be taken to an indoor soft play area or to the park for an hour or two. Babies in pushchairs are often completely covered up when they do go outside and then when we are outside, we may be wearing sunscreen that slows down vitamin D production.

Sun sense

Children should not be allowed to burn in the sun but this needs to be balanced with some exposure to sun during the summer months – 10 minutes of sun on their arms, legs, face and hands is thought to be enough.

However, if you are giving your child vitamin D supplements, you do not need to worry as much about sun exposure, especially if your baby has light skin.

Light-skinned people in general cannot take as much sun without burning and so may need to have two or three shorter exposures to the sun in one day. However, on hot summer days in bright sunshine and when you are abroad in a hot country, you need to be much more careful.

Babies should not be exposed to the sun to get vitamin D. Follow the vitamin D supplement advice from your baby’s doctor. However, that doesn’t mean staying inside all the time – just take sensible precautions to avoid your baby getting sunburned or overheating.