but how can you make sure children are getting enough?
Vitamin D, best known as the 'sunshine vitamin', is made in our bodies by the reaction of our skin to ultraviolet B (UVB) rays in sunlight. Unfortunately, between October and April, it is estimated that much of Western Europe, including about 90 per cent of the UK, lies too far north for the sunlight to have enough of the UVB rays necessary for making vitamin D in the skin - the UV index has to be greater than three. As a rule of thumb, it is said that if your shadow is longer than your body, the sun is not strong enough to have an effect.
Vitamin D is needed to regulate the amount of calcium and phosphate in the body and these nutrients are needed to keep teeth and bones healthy. It also stimulates the production of new cartilage building blocks within the joints. Vitamin D deficiency can lead to bone deformities such as rickets in children and bone pain and tenderness in adults as a result of a condition called osteomalacia (or soft bones).
New research indicates that vitamin D boosts the activity of immune cells, which fight infection and target cancer cells. The vitamin also plays a role in protecting us from some other chronic disorders such as heart disease, multiple sclerosis and diabetes.
Studies have found that people with lower levels of vitamin D in their blood are at higher risk of depression. Other problems associated with deficiency include constipation, muscle weakness, increased susceptibility to infection, poor growth and irritability.
However, although all the scientists may agree on how vital this vitamin is in the diet, doubts still remain over the dosage we should strive to achieve each day. Using the most natural method - sun exposure - we are told to have between ten and 15 minutes, two to three times a week. Others advocate a small daily sunbath. In all instances, sunscreen is not supposed to be applied.
SUPPLEMENTS
In supplement form, dosages are expressed either as micrograms (mcg) or IUs (international units) - and 1 mcg equals 40 IUs. The Department of Health recommends:
- all pregnant and breastfeeding women should take a daily supplement containing 10 mcg (0.01mg) of vitamin D to ensure the mother's requirements for vitamin D are met and to build adequate foetal stores for early infancy
- all babies and young children aged six months to five years should take a daily supplement containing vitamin D in the form of vitamin drops to help them meet the requirement set for this age group of 7-8.5 mcg (0.007-0.0085mg) of vitamin D a day
- babies fed infant formula will not need vitamin drops until they are receiving less than 500ml (about a pint) of infant formula a day, as these products are fortified with vitamin D
- breastfed infants may need to receive drops containing vitamin D from one month of age if their mother has not taken vitamin D supplements throughout pregnancy
- people aged 65 years and over and people not exposed to much sun should also take a daily supplement containing 10 mcg (0.01mg) of vitamin D.
FOOD SOURCES
Of course, there are certain foods that are rich in vitamin D. These include:
- baby milk or follow-on milk - if a child is drinking at least a pint a day of formula or follow-on milk, they are getting an adequate supply of vitamin D
- cod liver oil - as one teaspoonful contains a massive 450 IU, it is probably the richest source of vitamin D, but if you are of a more mature generation, like me, you may well remember your mother spooning that into your unwilling mouth!
- oily fish - which includes salmon, sardines, mackerel and tuna (100g of canned salmon contains about 547 IU of vitamin D, whereas the same sized portion of tuna yields 234 IU of the vitamin and mackerel 360 IU)
- fortified milks - one cup of soy milk contains 102 IUs. Check the vitamin D content of other milks on the packaging
- tofu - 100g of tofu contains about 157 IU
- eggs - a large egg contains 44 IU; the yolk accounts for 37 IU
- fortified fats and spreads - check the details on the packaging
- fortified breakfast cereals - check the details on the packaging
- mushrooms - this one is surprising, when you think of the conditions in which mushrooms are grown commercially. They love the dark and never see the sunlight. Portobello mushrooms (one cup, diced) contain about 384 IU; other types of mushrooms contain varying amounts of vitamin D.
Because most of the foods containing the 'sunshine vitamin' are either dairy or meat products, I recently turned my attention to whether children with a vegan diet were receiving enough vitamin D. I concluded that there are enough fortified dairy-free milks, spreads, cereals and mushrooms to ensure their intake of vitamin D was not much different from vegetarian or meat-eating children. So, time to get cooking.
GET COOKING
Although mushrooms may be a good source of vitamin D, they are also a bit like Marmite in that they are a food that seems to be either loved or hated. Much of the dislike appears to centre round the slightly slimy texture of mushrooms once they are cooked -hence my soup recipe (see box) recommending that the mushrooms be blended to a smooth consistency.
Their battleship grey colour lends nothing to their appeal, but swirl some single cream on the top and add a little parsley to finish it off. This soup can also be adapted to make a sauce for pasta - just add less liquid and make it a bit thicker.
You can also adapt many popular recipes to increase children's vitamin D intake. For example:
- the addition of one or two egg yolks to a creamy sauce will give it a gloss as well as adding vital vitamin D. Ensure it is cooked into the sauce
- use fortified milks instead of your usual cow's milk
- look out for cereals that are fortified with vitamin D, but watch out for the sugar content. Our children love cornflakes as an afternoon snack from time to time. Serve the cereal with the fortified milk and put bowls of chopped fruit on the table for them to add to the cereal if they choose.
- tuna canned in sunflower oil contains double the amount of vitamin D of tuna in brine or spring water.
June Graham is an early years practitioner at Cowgate Under 5s Centre, Edinburgh. www.cowgateunder5s.co.uk
MORE INFORMATION
- 'An essential guide to...vitamin D' by Mary Evans and 'Food groups - on balance' by Diana Hawdon at www.nurseryworld.co.uk
- List of foods rich in vitamin D, http://bembu.com/vitamin-d-rich-foods
- 'The new vitamin D debate' at Eating Well, www.eatingwell.com/nutrition_health/nutrition_news_information/the_new vitamin_d_debate
- NHS guidance, www.nhs.uk/Conditions/vitamins-minerals/Pages/Vitamin-D.aspx
- The Essential Guide to Vitamins, Minerals and Herbal Supplements by Dr Sarah Brewer
Ingredients100g butter
2 onions, finely chopped
700g Portobello mushrooms, sliced
2 pints vegetable stock (if using stock cubes, use a low salt variety)
3 pints milk
85g plain flour
2 tsp Worcestershire sauce
Seasoning, to taste
Single cream to swirl on top
]]
