Why you can trust Nutri Advanced  Every article on our site is researched thoroughly by our team of highly qualified nutritionists. Find out more about our editorial process.

Article at a glance:

Vitamin D is vital for growth, development and immune balance
Babies are at higher risk of vitamin D deficiency because they must avoid full sun exposure
Advice from UK Department of Health is that all children aged 0-4 should be given a daily supplement of 400 IU vitamin D (unless they’re getting enough from fortified formula milk)
Vitamin D is best supplemented as D3 (cholecalciferol) - the form naturally made in the skin following sun exposure

Why do babies need to supplement vitamin D?

The main source of vitamin D is not food, but sunlight. And babies under the age of 6 months are advised to stay out of the sun completely so this puts them at particularly high risk of vitamin D deficiency. Babies under 6 months, and in fact all children under 4, are considered at higher risk and advised to supplement regularly.

Vitamin D is crucial for infants, not just to grow healthy bones and prevent the bone-softening disease ‘rickets’, but also for normal physical and brain development, immune balance, heart health and even to support optimal levels of friendly bacteria. Vitamin D helps to control the amount of calcium and phosphate in our bodies; both of which are needed for healthy bones, teeth and muscles. It has antioxidant and anti-inflammatory actions and plays a crucial role in immune balance. There may even be links between vitamin D deficiency and risk of developing autoimmune problems such as type 1 diabetes and multiple sclerosis.

Do breastfed babies need vitamin D?

The level of vitamin D in breast milk will vary according to how much vitamin D mum gets. And unless it’s regular full body bare skin exposure to the sun, the likelihood is that it’s not enough, especially between the months of October – April, when vitamin D production is at its lowest. Breastfed babies will benefit from a supplement of 400IU vitamin D daily. The only time a breast fed baby doesn’t need additional vitamin D is when a mother is certain that she is getting enough, either through regular bare skin exposure to the sun, or by taking a daily supplement herself.

Researchers from the University of South Carolina discovered in a 6 month follow up pilot study, just how much of a challenge it is for breastfed babies to get enough vitamin D via breast milk:

In one study, researchers found that mothers who took a daily supplement of 6,400 IU gave their babies over 800IU vitamin D per litre of breast milk. In the same study however, those mothers who supplemented with only 400 IU daily gave a small fraction of just 50 IU in each litre of breast milk – nowhere near enough to give their babies what they needed. 

Considering how many new mums are likely to be low in vitamin D, and unlikely to be getting anywhere near enough themselves, the latest advice from the UK Department of Health is that breastfed babies from birth to one year should be given a daily supplement containing 8.5 – 10 mcg (400IU) of vitamin D daily to make sure they are getting enough.

How about formula fed infants?

The Department of Health also advises that all children aged 0 – 4 should be given a daily supplement of 400IU vitamin D. The only exception is infants fed fortified formula milk. In this case, vitamin D supplements are often only necessary for babies who are receiving less than 500ml daily, as levels above this will usually supply enough vitamin D. For formula fed babies, first check the ingredients label to work out how much daily vitamin D your baby is getting. If it’s less than 400 IU, add in an extra supplement to make up the difference. And remember that the amount will change according to how much formula your baby is getting, so you will probably need to add in a supplement once you start weaning, as total daily milk volume will start to reduce at this point.

What is the best form of vitamin D for babies?

It is generally advised that vitamin D is best supplemented as D3 (cholecalciferol), as this is the form made naturally in the skin from sunlight.  And this same form is recommended at any age - from babies, right through to old age. A tasteless, liquid version is convenient and safest for babies as this can be gently dropped into the mouth or easily added to a bottle.

How long should babies take vitamin D?

The Department of Health advises that all children aged 0 – 4 should take a daily supplement of 400IU vitamin D, all year round. It is important however to assess intakes from other sources, so exceptions to this are if you know your breast milk contains plenty of vitamin D, or if your baby is receiving more than 500ml fortified formula milk daily. In these cases, supplementation won’t be necessary.

1. Vitamin D & Health Report.  Scientific advisory committee on nutrition (SACN) 2016.  https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/537616/SACN_Vitamin_D_and_Health_report.pdf
2. Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM; Endocrine Society. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011 Jul; 96(7): 1911-30.
3. Hollis BW, Johnson D, Hulsey TC, Ebeling M, Wagner CL. Vitamin D supplementation during pregnancy: double-blind, randomized clinical trial of safety and effectiveness. J Bone Miner Res. 2011 Oct; 26(10): 2341-57. doi: 10.1002/jbmr.463
4. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010.
5. Wagner CL, Hulsey TC, Fanning D, Ebeling M, Hollis BW. High-dose vitamin D3 supplementation in a cohort of breastfeeding mothers and their infants: a 6-month follow-up pilot study. Breastfeed Med. 2006 Summer; 1(2): 59-70.
6. Wagner CL, McNeil R, Johnson DD, Ebeling M, Hulsey TC, Hollis BW. Health characteristics and outcomes of NICHD and Thrasher Research Fund (TRF): vitamin D (VITD) supplementation trials during pregnancy. Vitamin D Workshop, presented June 2012.
7. Norriss JM et al. Plasma 25-hydroxyvitamin D concentration and risk of islet autoimmunity.  Diabetes 2018 Jan; 67(1): 146-154. https://doi.org/10.2337/db17-0802
8. Munger KL, Levin LI et al. Preclinical serum 25-hydroxyvitamin D levels and risk of Type 1 diabetes in a cohort of US Military Personnel.  American Journal of Epidemiology: online February 3, 2013; March 1, 2013 print edition.
9. Rhead B, Baarnhielm M. et al. Mendelian randomisation shows a causal effect of low vitamin D on multiple sclerosis risk.  Neurol Genet. 2016 Oct; 2(5): e97.  Published online 2016 Sep 13. Doi: 10.1212/NXG.0000000000000097
10. Munger KL, Ascherio A et al. 25-hydroxyvitamin D deficiency and risk of MS among women in the Finnish maternity cohort.  Neurology.  Published online ahead of print doi: 10.1212/WNL. 0000000000004489

This website and its content is copyright of Nutri Advanced ©. All rights reserved. See our terms & conditions for more detail.

Nutri Advanced has a thorough research process and for any references included, each source is scrutinised beforehand. We aim to use the highest value source where possible, referencing peer-reviewed journals and official guidelines in the first instance before alternatives. You can learn more about how we ensure our content is accurate at time of publication on our editorial policy.