Vitamin D, the sunshine vitamin


Doctors and nutritionists tell use that Vitamin D is essential for optimal body function; it has an important role in maintaining bone structure and healthy teeth.

Science reveals that is more of a sun hormone which affects up to 2,000 genes in the body, deficiencies in adults may be one cause of a vast array of chronic conditions including osteomalacia (bone softening) and osteoporosis, which affects both men and women. Low levels in children are linked with rickets. A disease in which the bone tissue doesn’t mineralise well, leading to skeletal deformities. Rickets was virtually eradicated in the UK half a century ago as diets improved in the postwar boom and following the introduction of fortified foods. A report in 2013 by the chief medical officer highlighted a recent rise this preventable condition.

Exciting recent studies suggest other benefits too; vitamin D is important for a healthy heart and blood vessels. Emerging research reveals its importance in protecting against a host of health problems. Also, vitamin D boosts immunity which may prevent diseases like rheumatoid arthritis or diabetes. The exact role vitamin D plays in preventing these conditions continues to be explored by scientists and researchers alike. For those diagnosed with osteoporosis, vitamin D doesn’t offer a cure but may slow further bone loss, again more research is needed. Low levels of Vitamin D may be a factor in people suffering from winter depression, also known as seasonal affected disorder (SAD)

Furthermore, it can be used to treat skin conditions including vitiligo, scleroderma and psoriasis. Studies show a link between mood disorders and vitamin D; research hasn’t yet shown whether low vitamin D causes depression. Or that the levels drop as a result of depression, further research aims to clarify this.The body produces vitamin D in response to our skin’s exposure to sunlight; which is cleverly stored in the fatty tissues and the liver until needed. Sun exposure is an easy, reliable way for people to acquire vitamin D.

Here’s the science bit.

A chemical compound naturally present in the outer layers of skin converts on exposure to UV-B radiation to vitamin D3. 15 – 30 minutes, three times a week should be enough, for most of the UK population. Exposure time varies with age, skin colour, the season and time of day, for example with fair-skinned people 10 minutes may be sufficient. Consequently, people with darker skin tones will need longer exposure to obtain beneficial levels.

How to safely get it from the sun

The bare skin of the face, hands and arms gives the best results. Deficiency increases in people over 65 years of age, they have fewer skin receptors to synthesise UV-B on the skin. Spending all day indoors or only venturing out in the early morning or late evening, will not produce enough ultraviolet radiation to achieve adequate vitamin D. Moreover, sunscreen blocks UV-B radiation and prevents the manufacture of vitamin D. Although the brief sun exposure needed to produce sufficient vitamin D, is not enough to cause skin cancer, for those with concern about being in the sun, applying sunscreen after the first 15 minutes in the sun will keep skin protected.

Are you deficient?

An estimated 40-75% of the UK population live with silent vitamin D deficiency, which is increasing in northern latitudes, due to lifestyle changes and lower wintertime light levels and weaker sunlight during the months October – April. Lots of people don’t get enough sun exposure as they spend the majority of their day inside buildings. Also, the daily use of sunscreen, and covering up when outdoors in the spring and summer contribute to reduced levels.

Other at-risk groups

People who are housebound, along those who cover most of their bodies for cultural or religious reasons.  Living with a milk allergy, digestive conditions, anorexia and other eating disorders increases the risk of deficiency .  Along with strict vegans who may be susceptible to severe deficiencies. The other groups are pregnant women, breastfeeding mothers and their babies are especially vulnerable, and children under five years of age are also at risk.

How much do we need?

The recommended dietary allowance for adults and children over 8 years is 600 International Units (IUs) per day with the upper-level being 4,000 IUs.

It can be a challenge to obtain enough vitamin D from sun exposure and food alone. Although fat its soluble it is not abundant in the average UK diet, the richest foods sources are salmon,  sardines, egg yolks,ce cheese and mushrooms. To make this easier several foods are fortified with vitamin D including milk, yoghurt, breakfast cereals and orange juice. Our grandmas were right! Cod liver oil is an excellent source, 1 tablespoon gives more than twice the recommended daily dietary allowance.

The Department of Health guidance

The DOH suggests that people need a mix of sun exposure, food sources and supplements to maintain adequate levels of this essential vitamin. It is possible to obtain enough vitamin D without the aid of supplements, eating a healthy balanced diet and topping up sun exposure with a winter sun holiday will usually do the trick for those able to escape to sunnier climes during Britain’s long winter.

Finally, talk to your doctor or pharmacist before starting supplements of vitamin D.  This is especially important for people taking prescribed medication as vitamin D can interact with some drugs.  It worth noting that taking too many supplements can result in excessive calcium levels in the body, which can cause kidney damage, lead to calcium being leached from the body.

Please note:

This is for guidance only, it should not be regarded as a substitute for medical advice, examination or treatment given in person by an appropriately trained health professional.


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