This page is general information, not medical advice. Ask a doctor or pharmacist before starting a supplement, especially if you are pregnant, take medicines or have a medical condition.
In the UK, the NHS says sunlight is not strong enough to make enough vitamin D from October to early March. From late March or early April to the end of September, most people make enough from sunlight. The figures below say whose guidance each one is.
NHS advice (UK)
- Autumn and winter: adults and children over 4, including pregnant and breastfeeding women, should consider a daily 10 microgram (mcg) supplement.
- All year: the NHS advises a daily 10 mcg supplement for adults and children over 4 who are rarely outdoors (for example frail or housebound people), who live in a care home, or who usually cover most of their skin outdoors. It gives the same advice to people with dark skin, such as people of African, African-Caribbean or South Asian background.
- Children aged 1 to 4: 10 mcg a day, all year.
- Babies: breastfed babies, and formula-fed babies having less than 500 ml of formula a day, should have 8.5 to 10 mcg daily all year.
US figures (MedlinePlus)
MedlinePlus, from the US National Library of Medicine, lists recommended daily intakes. Children aged 1 to 18 and adults aged 19 to 70: 600 IU (15 mcg). Adults over 70: 800 IU (20 mcg). Pregnancy and breastfeeding: 600 IU (15 mcg). One mcg of vitamin D3 equals 40 IU, so the NHS 10 mcg is 400 IU. The US and UK figures differ, so follow the advice for the country you live in and your clinician’s guidance.
Related Reading
Upper limits
- NHS: adults, pregnant or breastfeeding women, older adults and children aged 11 to 17 should not take more than 100 mcg (4,000 IU) a day. Children aged 1 to 10: no more than 50 mcg (2,000 IU). Infants under 12 months: no more than 25 mcg (1,000 IU).
- MedlinePlus (US): 4,000 IU (100 mcg) a day for everyone aged 9 and over, 3,000 IU (75 mcg) for ages 4 to 8, and 2,500 IU (63 mcg) for ages 1 to 3.
The NHS says people with some medical conditions may need less, and that a doctor’s advice comes first. It warns that taking too much for a long time can cause too much calcium in the blood, which can weaken bones and damage the kidneys and heart. MedlinePlus says toxicity almost always comes from excess supplements and lists nausea, vomiting, confusion and kidney stones among the effects. The NHS says you cannot overdose from sunlight, though you should still protect your skin.
Food sources
The NHS lists oily fish (such as salmon, sardines, trout, herring and mackerel), red meat, egg yolks and fortified foods such as some fat spreads and breakfast cereals. It says liver should be avoided in pregnancy. It adds that cow’s milk is generally not a good source in the UK because it is not fortified.
