By Cathy Monaghan, RD MINDI, Paediatric Dietitian.

Adapted from the HSE Guidelines for Vitamin D supplementation in Ireland.

Vitamin D, often referred to as the “sunshine vitamin,” is unique because it can be synthesized by the body when the skin is exposed to sunlight. In a country like Ireland, where sunshine can be scarce, obtaining sufficient levels of Vitamin D solely through sunlight can be challenging, especially during the winter months. Therefore, it becomes essential to consider alternative sources to meet the recommended daily intake.

One of the primary roles of Vitamin D is in promoting bone health by aiding in the absorption of calcium and phosphorus. Sufficient levels of this vitamin are crucial, particularly for growing children, as it ensures proper bone development and strength, reducing the risk of conditions like rickets and osteoporosis later in life.

Beyond its role in bone health, Vitamin D also supports immune function, making it a valuable nutrient for bolstering the body’s defenses against infections and illnesses. Studies have shown that individuals with lower levels of Vitamin D may be more susceptible to respiratory infections, a concern that holds particular relevance in today’s health landscape.

So, how much Vitamin D does your family need? The recommended daily intake varies by age and life stage, with infants, children, adults, and seniors each having specific requirements. While sunlight remains an excellent natural source, it’s often insufficient, especially during the winter months. Therefore, incorporating Vitamin D-rich foods into your family’s diet, such as fatty fish, fortified dairy products, and fortified cereals, can help bridge the gap.

Supplementation is another option to ensure adequate intake, particularly for those at risk of deficiency, such as individuals with limited sun exposure or certain medical conditions.

Low vitamin D levels in our bodies can contribute to:

  • Rickets in children – a condition that leads to soft bones causing severe bone deformities such as bowed legs and spine curves.

  • Rickets in adults – a condition known as osteomalacia. This can cause bone fractures, muscle weakness and bone pain.

    Research also shows that vitamin D also plays an important role in helping the immune system. It may help prevent:

    • diabetes

    • heart disease

    • rheumatoid arthritis

    • MS (multiple sclerosis)

    • some forms of cancer

If you have black or brown skin, for example if you have an African, African-Caribbean or south Asian background, you are more likely to have a baby with low levels of vitamin D. This is because people with black or brown skin may not make enough vitamin D from sunlight.

Why do babies need vitamin D?

Your baby needs vitamin D because:

  • their skin is very sensitive to the sun and they should not be in direct sunlight
  • their food (breast milk or solid foods) may not have enough Vitamin D in it
  • between 0 to 12 months babies grow very quickly and have a greater need for vitamin D to help form strong bones

Vitamin D for babies 0 to 12 months

Give your baby 5 micrograms of vitamin D3 as a supplement every day from birth to 12 months if they are:

  • breastfed or

  • taking less than 300ml of infant formula per day

You do not need to give your baby a vitamin D supplement if they are fed more than 300ml of infant formula a day. Infant formula comes with vitamin D added to it.

All breastfed babies need a vitamin D supplement from birth, even if you took vitamin D during pregnancy.

There are many suitable infant vitamin D3 supplements available to buy in Ireland. These are available in liquid form and can be given to your baby by dropper or by oral syringe. They are not expensive. Do not use a multivitamin. Use a supplement that contains vitamin D only. Please talk to your pharmacist if you need help choosing one.

Vitamin D supplements for children age 1 to 4

Children age 1 to 4 need a vitamin D supplement during the winter months from Halloween until St. Patrick’s Day. This is because they cannot get enough from the sun or their diet in winter months. They need vitamin D for healthy bones and teeth.Liquid drops of a vitamin D-only supplement are usually best for children age 1 to 4. Give them 5 micrograms every day during winter. Ask your pharmacist if you need advice on choosing a supplement.

Adults and Children over 5 years.

If you choose to take a vitamin D supplement, try:

  • 10 micrograms for healthy children age 5 to 11
  • 15 micrograms for healthy teenagers and adults age 12 to 64

If you were prescribed a higher dose by your doctor then you should continue to take it.


People at risk of vitamin D deficiency

Some people will not get enough vitamin D from sunlight because they have very little or no sunshine exposure. Or, they do not get enough vitamin D from sunlight. You may need to take a daily supplement of vitamin D throughout the year if you:

  • are not often outdoors – for example, if you’re frail or housebound
  • are in an institution like a care home
  • usually wear clothes that cover up most of your skin when outdoors
  • have black or brown skin

Effects of taking too much vitamin D

Taking too many vitamin D supplements over a long time can cause too much calcium to build up in the body (hypercalcaemia). This can weaken the bones and damage the kidneys and the heart. Do not take more than 100 micrograms of vitamin D a day as it could be harmful. This applies to adults, the elderly, and children aged 11 to 17 years. Children aged 1 to 10 years should not have more than 50 micrograms a day. Infants under 12 months should not have more than 25 micrograms a day. Some people have medical conditions that mean they may not be able to safely take as much. If in doubt, talk to your GP.

Follow the advice of your GP if they recommend that you take a different amount of vitamin D.


Foods rich in vitamin D

Your family can get vitamin D from a range of foods but you are unlikely to meet your requirements to prevent deficiency.

Foods rich in Vitamin D include:

  • oily fish

  • liver

  • egg yolks

  • fortified foods such as some fat spreads, milk and breakfast cereal

Continue to include a range of foods in your diet but also supplement with Vitamin D for each age group as explained above. If you would like to discuss further, please consider a 1:1 consultation with one of our expert Dietitians.

Adapted from the HSE Guidelines for Vitamin D supplementation in Ireland. If you are worried about your families intake you can book a 1:1 Consultation here.