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The Importance of Vitamin D

A nationwide survey conducted by the NHS in the United Kingdom showed that more than 50% of the adult population have insufficient levels of vitamin D.

Sunlight is a well-known source of vitamin D, but what else can we do to top up our vitamin D levels, especially if we are stuck inside?

This article will provide clarity on what exactly Vitamin D is, how to obtain good sources of it and whether we should consider taking supplements.

What is vitamin D?

Vitamin D helps regulate the amount of calcium and phosphate in the body. These are the nutrients needed to keep bones, teeth and muscles healthy.

The NHS states 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. A clinical review published by the British Medical Journal in 2010 presented evidence that vitamin D deficiency may increase the risk of developing several chronic conditions, such as:

  • Heart disease
  • Diabetes
  • Cancer

However, the results from this particular study were inconclusive and did not provide a strong enough argument but has since sparked a debate and further research exploring in the importance of Vitamin D.

How do we source vitamin D?

Vitamin D is somewhat unusual from other vitamins, in that we obtain it from two difference sources: sunlight and our diet.


From about late March/early April to the end of September, most people should be able to get all the vitamin D they need from sunlight.

The body creates vitamin D from direct sunlight on the skin when outdoors. It is said that 10-15 minutes of sun exposure to your bare skin will help build up stores of vitamin D. This should be done with care, ensuring we are not participating in long periods of exposure without sun protection. Sitting by a window doesn’t count, as UVB rays can’t penetrate glass. Never be tempted to stay in the sun for longer than 10-15 minutes without sun protection, as exposure increases the risk of skin damage and cancer.

Dietary sources

When sunlight is limited, what we eat can play a part instead. There are few foods that contain vitamin D in sufficient quantities, so it can be difficult to get enough from diet alone. However, we can find small amounts of vitamin D in some food sources, such as:

  • Oily fish – such as salmon, sardines, herring and mackerel
  • Red meat
  • Liver
  • Eggs
  • Fortified foods – such as most fat spreads and some breakfast cereals

The NHS argues that 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.

If you’re a vegan or strict vegetarian, you should monitor your vitamin D levels more closely as most of the foods which naturally contain vitamin D are products of animal origin, so looking out for foods which have been fortified instead.

The NHS also states it can be difficult to get enough vitamin D from food alone, so people should consider taking a daily supplement containing 10 micrograms of vitamin D. Some people may choose to do so, particularly during the autumn and winter months where the sun is not strong enough to provide the body with enough vitamin D. There also are people that could benefit more from Vitamin D supplements, including those who…

  • aren't often outdoors – for example, if you're frail or housebound
  • are in an institution, such as a care home
  • usually wear clothes that cover up most of your skin when outdoors
  • are unable to be outside for longer periods of time (e.g. during social distancing measures)

What is vitamin D deficiency?

Vitamin D deficiency is when the body does not have enough vitamin D to properly absorb the required levels of calcium and phosphate. There are different levels of severity when measuring vitamin D deficiency, but even mild to moderate vitamin D deficiency can lead to bone pain and weakening of the bones (known as osteoporosis). This could make you more likely to fracture a bone if you had a fall. The more severe levels of deficiency can lead to the development of rickets in children and osteomalacia in adults.

Osteomalacia develops because of softening of the bones. The main symptom of osteomalacia is a dull, throbbing and often severe bone pain that usually affects the lower section of the body. Osteomalacia can also result in muscle weakness. If you are experiencing these symptoms, then it is recommended that you discuss with your GP.

The NHS concludes that, by simply trying to making more of an effort to get outdoors during the lighter months, remembering to aim for small and frequent bursts of sun exposure rather than long sessions (to prevent skin damage), and eating food rich in sources of vitamin D should be enough to reduce risk of vitamin D deficiency.