Vitamin D is known as the ‘sunshine vitamin’ because our bodies make most of our requirements from the action of sunlight on our skin. Just 15-20 minutes of sun (without sunscreen) every day between 11am and 3pm in spring and summer provides enough vitamin D for most of the year. Foods and supplements containing vitamin D top up our vitamin levels during the summer, but take on an important role during winter when we’re unable to make it from sunlight.

Vitamin D deficiency: the facts

Vitamin D is essential for bone health. It enables the calcium we eat to be absorbed into our bodies. Without vitamin D, we wouldn’t absorb enough calcium. Calcium keeps our teeth and bones strong. Vitamin D deficiency can cause tiredness, aches and pain, and can lead to bone deformities and osteoporosis (weak, fragile bones) in later life. Recent research suggests that vitamin D deficiency may also increase the risk of chronic conditions, e.g. heart disease, cancer and multiple sclerosis.

Studies show that Brits have a low intake of vitamin D and that over 20% of women and teenagers are deficient in vitamin D. This is probably due to the British weather patterns, our attitudes towards sun exposure, low oily fish intake and obesity.

The Department of Health recognises that pregnant women are at a higher risk of vitamin D deficiency, and recommends supplementation.

Why are pregnant women at risk?

Your growing baby needs calcium to form strong bones. During pregnancy, your body adapts by absorbing calcium more efficiently from your diet, to pass to your baby. Vitamin D is needed for this process. If you don’t have enough vitamin D, calcium may be taken from your bones to supply your baby, leaving your bone health at risk. You also need to provide your baby with vitamin D stores. This is to ensure your newborn has enough vitamin D for their first few months of life, and to prevent rickets (bone deformities).

Giving your baby the best start

Follow these steps to give your baby the best start and protect your own bone health:

  • Take a vitamin D supplement every day – all pregnant women should take a supplement containing 10 micrograms of vitamin D every day. You can take vitamin D supplements in addition to folic acid supplements, or you may wish to take daily pregnancy multivitamin tablets or Healthy Start Vitamins. Pregnancy and Healthy Start vitamins include vitamin D, as well as folic acid and other vitamins.
  • Catch some rays – expose your arms and face for 15-20 minutes a day before adding sunscreen. Women with darker skin will need longer than this.
  • Something fishy! – Oily fish is the best natural source of vitamin D. Try to eat one portion (140g) a week, e.g. salmon, mackerel, sardines, pilchards and fresh tuna (tinned tuna doesn’t count).
  • Other foods – eggs and red meat are good sources of vitamin D. Breakfast cereals and spreads/margarines are often fortified with vitamin D. Check the label of your usual brands to see if they are fortified. If not, consider changing brands.
  • Be weight-wise – women who are overweight or obese at the start of their pregnancy may have lower levels of vitamin D in their blood. Try losing weight before pregnancy, and try not to put on too much weight during pregnancy – about 1 stone (6kg) weight gain is appropriate. Ask your midwife for more information.
  • Mind the gap! – deficiency is more likely in women who have several babies with short gaps in between. This is due to the vitamin’s stores getting used up and not having a chance to re-build.
  • Are you in another ‘at risk group’? – Do you have limited exposure to sunlight, e.g. covering up for cultural reasons or housebound? Do you have darker skin, e.g African, African-Caribbean or South Asian origin? If yes, it’s likely your body can’t make enough vitamin D. It’s recommended that you take a daily supplement containing 10 micrograms of vitamin D all the time. Taking vitamin D pre-conception will help optimise vitamin D stores for pregnancy.