The importance of Vitamin D

Wellbeing | Pregnancy | | Helen Farnsworth

Are you getting enough vitamin D?

Around 1 in 6 adults have vitamin D levels lower than government recommendations, according to the latest Diet and Nutrition Survey data in the UK.1 Similarly, dietary surveys in young children have also shown that some children aged 1-3 are not meeting nutritional requirements for vitamin D and some other important nutrients.2,3 But why is vitamin D important, and how do we get it?

Why is vitamin D important?

Vitamin D helps regulate the amount of calcium and phosphate in our bodies, helping to keep bones, teeth and muscles healthy. It also contributes to the normal function of the immune system in adults.

In children, vitamin D is needed for normal growth and development of bone, and also helps normal functioning of the immune system.

A lack of vitamin D can lead to bone deformities such as rickets in children, and bone pain caused by a condition called osteomalacia in adults.

Where is vitamin D found?

Vitamin D is only found in a few foods such as oily fish and eggs, as well as in some foods that have been fortified with vitamins and minerals, like breakfast cereals.

We also get vitamin D from the reaction of the sun’s UVB with skin. In fact, in the summer months, the majority of adults and children aged 4 years and older will probably get sufficient vitamin D from being outdoors in the sunshine, and by following a healthy, balanced diet.

However, during the winter months, when UVB rays are limited, our intake falls short. That’s why the government recommends all adults and children over 4 years old take a daily supplement containing 10 mcg of vitamin D during the autumn and winter. And for those who have very little sun exposure, this guidance applies all year round.

Vitamin D – in pregnancy

This same advice applies during pregnancy. If you’re not sure whether you need to take a vitamin D supplement during the spring and summer months of your pregnancy, talk to your healthcare professional.

You can also tailor your diet to include more vitamin D, for example by:

  • Incorporating a portion of fortified breakfast cereal served with semi-skimmed/skimmed milk into your daily diet – opt for lower sugar and salt, and higher fibre options, as these are healthier.
  • Eat at least one (but not more than two) portions of oily fish per week, such as salmon, trout, mackerel and herring. (But remember the advice on which fish to avoid during pregnancy – e.g. raw fish, shellfish, shark, swordfish, marlin and fish liver oil supplements). (Please note, with tuna you should have no more than 2 tuna steaks or 4 medium size cans of tuna per week).

For more information on what makes up a healthy balanced diet during pregnancy, follow the guidance of the Government’s Eatwell guide. But remember there’s no need to balance every meal you eat, so long as you aim for balance throughout your day and across the week.

It’s also important to note that the advice on vitamin D supplementation during pregnancy is in addition to the recommendation for 400 mcg of folic acid up to the 12th week of pregnancy. For further advice on folic acid, and vitamin supplements in pregnancy, see our fact sheet‘vitamins and supplements to take during pregnancy'.

Vitamin D – for babies & toddlers

Although summer sunlight on the skin is the main source of vitamin D for older children and adults, it’s really important to keep your little one’s skin safe in the sun – which usually means covering them up, or keeping them in the shade. Since this limits their exposure to the sun, food and vitamin D supplements are really the only suitable source of vitamin D.

For babies aged up to one year, the recommendation for vitamin D supplementation is that:

  • Breastfed babies from birth to 1 year of age should be given a daily supplement containing 8.5 to 10 micrograms
  • Formula fed babies under 1 year of age and drinking more than 500 ml don’t need additional vitamin D supplementation, as formula milk is already supplemented.

Infants from 1 – 4 years of age are recommended to be given a daily supplement containing 10 micrograms of vitamin D.

Once your baby has begun weaning, there are more options to include vitamin D in their diet. For example:

  • Serve a portion of vitamin D fortified baby cereal for breakfast, made with baby’s usual milk.
  • If there is no known allergy to fish, try to incorporate some oily fish into baby’s diet, taking care to avoid raw fish, raw shellfish, shark, swordfish or marlin, and stick to the general recommendations – i.e. ideally two portions of fish a week, at least one of which should be oily. The recommendation is for boys to have a maximum of four portions of oily fish per week and girls no more than two portions a week.
  • If there is no known allergy to egg, serve some egg dishes; egg is a good source of protein, and egg yolks contain vitamin D. As with pregnancy, British, red lion stamped eggs are fine for babies to have lightly cooked; otherwise make sure they are thoroughly cooked before serving.
  1. UK National Diet and Nutrition Survey Rolling programme Years 9 to 11 (2016/2017 to 2018/2019)
  2. Diet and nutrition survey of infants and young children. Department of Health UK, 2011. 
  3. EFSA Scientific Opinion on nutrient requirements and dietary intakes of infants and young children in the European Union. EFSA Journal 2013; 11 (10): 3408.