Vitamin D has been the subject of unprecedented news and research of the past few years, with a deficiency believed to cause numerous health problems.
The primary known role of vitamin D is to maintain proper calcium levels in the body. The bones, nervous system and immune system depend on calcium for proper functioning. Without vitamin D, the body is unable to absorb and use calcium efficiently.
Vitamin D from sunlight
Importantly in the UK, our skin simply isn't able to make vitamin D from October to March, as the sunlight hasn't got enough UVB radiation. During these times, seeking dietary vitamin D or supplements is essential.
Our body creates most of our vitamin D from direct sunlight on our skin. Sun exposure does satisfy our vitamin D requirements, but it also damages skin and the NHS tell us "The longer you stay in the sun, especially for prolonged periods without sun protection, the greater your risk of skin cancer."
We are told "If you plan to be out in the sun for long, cover up with suitable clothing, seeking shade and applying at least SPF15 sunscreen". The problem with this advice is too little time outside and heavy sunscreens that prevent the skin from absorbing sunlight may help prevent wrinkles and skin cancer but may also lead to vitamin D deficiency.
Does sunscreen stop vitamin D absorption?
The simple answer is yes it does! A high SPF not only prevents UV rays from damaging the skin, but it also prevents the absorption of vitamin D from sunlight. Using an SPF 8 sunscreen cuts the amount of vitamin absorbed from the sun by 95%, and those with higher SPF rates reduce vitamin D absorption to virtually zero. When sun exposure is limited or blocked with high-SPF sunscreens, you must get enough dietary vitamin D intake (food or supplements) to compensate for the lack of the vitamin absorbed from sunlight.
Because during the winter it is impossible to get enough vitamin D from the sun in the UK, and during the summer it is advisable to use sunscreen, it is clear that vitamin D supplements are important all year round.
Vitamin D through a sunny window
An important but little known fact that most people are unaware of is you can’t make vitamin D from sitting indoors by a sunny window because ultraviolet B (UVB) rays can’t get through, but you can still burn.
Vitamin D advice for young children
The NHS currently advise us that from March to October in the UK, children and babies should:
- cover up with suitable clothing
- spend time in the shade (particularly from 11am to 3pm)
- wear at least SPF15 sunscreen
- to ensure they get enough vitamin D, children aged under five are advised to take vitamin D supplements even if they do get out in the sun.
Dietary sources of vitamin D
We can get some vitamin D from some foods, rich sources include oily fish such as salmon, mackerel and sardines, as well as meat and eggs.
Vitamin D is also added to all infant formula milk, as well as some breakfast cereals, soya products, dairy products, powdered milks and fat spreads.
The amounts added to these products can vary and may only be added in small amounts.