This page takes much of its information from the British NHS website. Click here for the original page
Vitamin D is central to many processes in the body, from helping to regulate the amount of calcium and phosphate in the body, keeping bones, teeth and muscles healthy; to the production of serotonin, a hormone and neurotransmitter central to our physiological happiness.
A lack of vitamin D can lead to bone deformities such as rickets in children, and bone pain and tenderness as a result of a condition called osteomalacia in adults.
Good sources of vitamin D
From about late March/April to the end of September, most of us should be able to get all the vitamin D we need from sunlight on our skin. The vitamin is made by our body under the skin in reaction to UVB radiation in sunlight.
If you are out in the sun, take care to cover up or protect your skin with sunscreen before you turn red or get burnt. Between October and March anywhere further north than about 40 degrees (Madrid, New York, Beijing) does not receive adequately intense UVB radiation for skin to produce any vitamin D from sunlight.
Read more about how we get vitamin D from sunlight.
Vitamin D is also found in a small number of foods. Good food sources are:
- oily fish – such as salmon, sardines, herring and mackerel
- red meat
- egg yolks
- fortified foods such as most fat spreads and some breakfast cereals
Another source of vitamin D is dietary supplements.
In the UK, cows’ milk is generally not a good source of vitamin D because it isn’t fortified, as it is in some other countries such as Canada.
How much vitamin D do I need?
Babies from birth to one year need 8.5 to 10 micrograms (8.5-10mcg) of vitamin D a day.
Children from the age of one year and adults need 10 micrograms (10mcg) of vitamin D a day. This includes pregnant and breastfeeding women and population groups at risk of vitamin D deficiency (those with minimal exposure to sunshine and those from minority ethnic groups with dark skin).
From about late March/April to the end of September, most of us should be able to get all the vitamin D we need from sunlight on our skin.
Should I take a vitamin D supplement?
Because vitamin D is found only in a small number of foods, it might be difficult to get enough from foods that naturally contain vitamin D and/or fortified foods alone. So everyone, including pregnant and breastfeeding women, should consider taking a daily supplement containing 10mcg of vitamin D.
Between late March/April to the end of September, the majority of people aged five years and above will probably obtain sufficient vitamin D from sunlight when they are outdoors. So you might choose not to take a vitamin D supplement during these months.
However, some groups of people will not get enough vitamin D from sunlight because they have very little or no sunshine exposure. So the Department of Health recommends that people should take a daily supplement containing 10mcg of vitamin D throughout the year if they:
- are not often outdoors, such as those who are frail or housebound
- are in an institution such as a care home
- usually wear clothes that cover up most of their skin when outdoors
People from minority ethnic groups with dark skin, such as those of African, African-Caribbean or South Asian origin, might not get enough vitamin D from sunlight – so they should consider taking a daily supplement containing 10mcg of vitamin D throughout the year.
What happens if I take too much vitamin D?
Taking too many vitamin D supplements over a long period of time can cause more calcium to be absorbed by the body than can be excreted. This leads to high levels of calcium in the blood (hypercalcaemia).
Too much calcium in the blood can weaken the bones and damage the kidneys and the heart.
If you choose to take vitamin D supplements, 10mcg a day will be enough for most people.
Do not take more than 100mcg of vitamin D a day, as it could be harmful. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11-17 years.
Children aged 1-10 years should not have more than 50mcg a day.
Infants under 12 months should not have more than 25mcg a day.
Some people have medical conditions that mean they may not be able to safely take as much. If in doubt, you should consult your doctor. If your doctor has recommended you take a different amount of vitamin D, you should follow their advice.
Your body doesn’t make too much vitamin D from sun exposure, but always remember to cover up or protect your skin if you are out in the sun for long periods, to reduce the risk of skin damage and skin cancer.
David is a Mindset Trainer and Coach specialising in habituating scientifically proven exercises as natural daily routines. He is the founder of A Good Way To Think, and provides habit-forming coaching via our partner platform: Coach.Me