Why we need vitamin D:
the super supplement

One of the most commonly held beliefs about vitamin D is that its only use is to help keep your bones healthy. But this powerful nutrient can actually play a role in a number of different areas of wellbeing. Here’s all you need to know about vitamin D and what it could do for you. 

What is vitamin D?

Despite its name, vitamin D is more than a vitamin - it's closer to a hormone that the body can synthesise under the right conditions. Regardless, we need to consume it regularly in order to maintain overall health and wellbeing.

How is vitamin D produced?

The trigger for vitamin D synthesis is the sun, which emits UVB light that hits our skin. The UVB light reacts with a type of cholesterol found in the deeper layers of the skin, which produces a vitamin D precursor called pre-vitamin D. This is then converted to active vitamin D (calcitriol) by the liver and kidneys, and it's this form that travels around the body to interact with cells.

Due to the varying amounts of available sunshine, it's hard to get adequate vitamin D levels from sun exposure in the UK. This is especially true outside the summer months; a good rule of thumb is that if your shadow is taller than you are, you're not making vitamin D. We can also get small amounts from our diet. Meals that include eggs, oily fish, foods fortified with vitamin D, and mushrooms are all popular dietary sources of the vitamin.

What does it do in the body?

Vitamin D has many functions within the body, including:

  • Balancing calcium levels in the body (including in the bones)
  • Supporting healthy levels of white blood cells
  • Aiding in immune function during infection

This list isn't at all exhaustive and, in fact, scientists are only just scratching the surface of what vitamin D may help with. More recently, research has found that it may even help to reduce inflammation — suggesting it could aid in the recovery of a disease or condition that has inflammation as a characteristic.1

Are you getting enough vitamin D?

As we've already said, the sun is the trigger for vitamin D synthesis, but does this mean we get enough from sun exposure? It depends. Everyone produces vitamin D at different rates, and many are at risk of vitamin D deficiency.

Healthspan Medical Director Dr Sarah Brewer says: 'Public Health England recommends that everyone over the age of one year should take a daily supplement providing 10mcg vitamin D during autumn and winter. This is very much a minimum to prevent deficiency diseases – I believe that most adults would benefit from taking 25mcg (1.000 IU) per day, increasing to 50 mcg (2,000 IU) per day from the age of 50 onwards, when your ability to synthesis vitamin D in the skin starts to decline. Choose a vitamin D3 (cholecalciferol) supplement which is the same form made in the skin by the body on exposure to sunlight, and which is more effective in producing active vitamin D3 (calcitriol) than the plant-based vitamin D2 (ergocalciferol) form.'

In April 2020, this advice was updated to recommend that anyone spending a large amount of time indoors should take a vitamin D supplement during the spring and summer, too.

Who is most at risk of vitamin D deficiency?

Those who are most vulnerable to vitamin D deficiency include:

  • People who live in cold climates (such as the UK)
  • People who get little direct sun exposure e.g. someone who works in an office job
  • Those with a long-term illness that tends to confine them indoors
  • People who keep the majority of their skin covered e.g. for religious reasons
  • Dark-skinned people
  • The elderly
  • People who wear sunscreen or use products that contain SPF regularly

However, everyone is at high risk of becoming vitamin D-deficient, especially during winter. In fact, according to research, low vitamin D levels might explain why we're more prone to becoming sick during flu season - another reason why you should get your levels checked at the start of each winter. Even living in a city over the countryside may increase the risk of becoming deficient.

Vitamin D: the benefits

There's a significant amount of emerging research to suggest vitamin D may help with specific health conditions.

Vitamin D and immunity

Vitamin D is crucial for activating and regulating infection-fighting T-cells. Vitamin D is needed to activate the transformation into the killer cells that help destroy alien pathogens, or the cells that help the immune system 'remember' a given pathogen, so it can deal with it more effectively if it is encountered again.

Other breakthroughs show vitamin D not only helps to ward off infection and disease but also protects against autoimmune conditions. Vitamin D helps stop the body from attacking healthy tissues by triggering the development of regulatory T-cells – these help to recognise the difference between foreign invaders and 'self', so the immune system does not attack its own cells.

Vitamin D and muscles

Muscle weakness can occur due to vitamin D deficiency, manifesting itself in a feeling of heaviness in the legs, difficulty mounting stairs and raising from a chair, and tiring easily. But a study in the American Journal of Clinical Nutrition found that this is reversible through nutrition.

Vitamin D and mood

One of the most talked about symptoms of vitamin D deficiency is feeling low or possibly displaying symptoms of Seasonal Affective Disorder (SAD). As the nights draw in, sufferers take no pleasure in everyday activities, feel irritable and lethargic, sleep more, find it harder to get up and crave sugary carbohydrates.

As ever more research is conducted into the role vitamin D may play in mood, it's becoming clearer just how essential this vitamin can be for many people.

Vitamin D and exercise

If you're an athlete, or just fitness-conscious, knowing your vitamin D status should be on your priority list. Recent research suggests that there could be a link between your sports performance and how optimal your vitamin D levels are.

In one study in the Journal of Sport Sciences, researchers created a trial that looked at the effects of supplementation on a group of UK athletes and non-athletes. Initially, they found that 62% of athletes and 73% of non-athletes had vitamin D deficiency.

When the same groups were given 5000IU of vitamin D a day for 8 weeks, it not only significantly increased their vitamin D levels, but it also had an impact on their physical performance. For instance, those who were given the supplement found a significant improvement in their 10m sprint time and vertical jump height. Find out more about vitamin D and exercise here.

Vitamin D and bone health

Although vitamin D is essential for every age, it may be especially important for babies and children to get a sufficient amount. This is because vitamin D can helps maintain optimal calcium levels to support the growth and development of healthy teeth and bones in young children.

Children who don't get enough vitamin D may be at risk of developing osteomalacia - the softening of the bones. Osteomalacia can lead to bowing of the bones, particularly of the larger bones (such as leg bones).

Making sure you get enough vitamin D for bone health isn't limited to just children: it's also important for the elderly. One study, published in the International Journal of Gerontology, looked at the effects of vitamin D supplementation in combination with low-level exercise amongst the elderly, and found that this combination was effective at reducing falls in the elderly participants.

For more information on how vitamin D can help support your overall health and wellbeing, head to our advice centre.

Nothing beats a healthy, balanced diet to provide all the nutrients we need. But when this isn't possible, supplements can help. This article isn't intended to replace medical advice. Please consult your healthcare professional before trying supplements or herbal medicines.



Missed Promotion: {{missedPromo.DisplayText}}






(Basket total above includes promotional prices. You have SAVED £{{cart.TotalPriceListDiscount| number : 2}} today.)

Review basket and check out

Your basket is currently empty

Have a query? Chat now