What is Vitamin D?


Vitamin D is important for good overall health and strong healthy bones. This is a factor in making sure that your muscles, heart, lungs and brain work well so that your body can fight infection. There are other variations of vitamin D but D3 is the main source which is most beneficial towards the human body.

Vitamin D plays a vital role in the development and maintenance of bones also supporting the immune system and mood. This is different from other vitamins because the human body has the ability to produce this on its own. Vitamin D is produced under the skin from direct sun exposure to sunlight. This is essential and the two main functions in the body include supporting the absorption of the calcium and phosphorus into your bones and to manage communication between the cells in the body.

A simple method which your body can use to create vitamin D is from a source of sunlight; you can also create vitamin D from supplements and also from certain foods you consume.

Once Vitamin D is in your body, your body uses it to manage the quantity of calcium in your blood, bones and gut to help cells all over your body to communicate properly.


What are the Benefits of Vitamin D?

• Good for the immune system which helps to fight infection by attacking and destroying damaging bacteria and viruses.

• Improves muscle function

• Improves cardiovascular function, for a healthier heart and circulation

• Improves respiratory system, for healthier lungs and airways

• Improves brain development

• Good for bone health as vitamin D has a well-established goal in maintaining normal calcium levels and the growth and maintenance of strong bones and teeth.

vitamin D diagrambenefits of vitamin D


How Does Vitamin D work? 

• Vitamin D mainly comes from your skin when exposed to sunlight. After that, your body goes through a number of chemical processes to change it so your body can make use of it

• When your skin is exposed to the sun, it produces vitamin D and sends it to your liver; this is the same if you consume foods or supplements that contain vitamin D.

• After this process, your liver then changes so a substance known as 25 (OH)D. When your doctor mentions your vitamin D levels they look at the amount of 25(OH)D which you have in your blood.

• The chemical is sent all over your body where different tissues including your kidney, turn into activated vitamin D. The vitamin D inside your body is then activated.

• The key duty which vitamin D performs include managing calcium through your bones, blood and gut and helps all the cells in your body to communicate properly.


What are the Sources that contain Vitamin D? 

The most effective way to get source of vitamin is through exposure to sunlight for about 15 minutes of sunshine 3 to 4 times per week (without sunscreen) is sufficient for most people to maintain normal vitamin D levels. Exposure to sunlight during the summer months (hottest months of the year commonly July and August) are when vitamin D is most effective.

There is a high variety of different food sources containing Vitamin D here are some common examples: 

• Cod liver oil

• Beef liver

• Egg yolks

• Margarine spreads

• Spinach

• Soy beans

• Different types of fishes such as trout, tuna, mackerel, salmon

• Calcium and dairy foods/drinks such as cheese, soya milk, orange juice, yoghurt

• Cereals such as corn flakes, weetabix, bran flakes etc./oatmeal

• Fruits such as mangoes, peaches, apricots, avocado 

• Vegetables such as mushrooms, peppers, broccoli 

Vitamin DVitamin D3 vitamin D supplements


What is Vitamin D deficiency? 

Vitamin D deficiency or lack of vitamin D is when you are not consuming enough vitamin D to keep your body healthy and functioning in the way it should be. This is mainly due to distance from the equator as the further you live from the equator, the weaker the sun rays and ability to trigger Vitamin D consumption.

During the winter period there are less hours of daylight and the sun is not as strong as it would in the summer due to cold weather and shorter days. Pollution is worse during the summer period which can form light pollution blocking sunlight from reaching people. An example would include traffic and high industrial areas.

If you do get enough vitamin D in your system then you are at greater risk of developing conditions such as diabetes, heart diseases, weight gain.


What are the Symptoms of Vitamin D deficiency?

• Getting sick or infected often especially colds and flus this can weaken your immune systems.

• Fatigue/Tiredness

• Moodiness

• Bone and muscle pain

• Depression

• Impaired wound healing (vulnerability to cuts, bruises slow healing of wounds after surgery ) 

• Weakness


Who is at greater risk of Vitamin D deficiency?

• People who stay indoor for long periods

• Men and women aged 65 and over

• Pregnant and breastfeeding women

• Children under the age of 5

Vitamin D deficiency


How is Vitamin D deficiency Diagnosed?

Talk to your GP if you believe you are experiencing vitamin D deficiency. If this is the case then your GP or hospital doctor can arrange a blood test for you. This blood test measures a form of vitamin D in the blood known as ‘serum vitamin D’ or 25-hydroxyvitamin D. Your GP may also require calcium levels in your blood if necessary.

Vitamin D supplements come in both micrograms (ug or mcg) and International Units (IU). The UK Government has issued public health advice stating that everyone should consider taking Vitamin D supplements during the autumn and winter.


What are the recommended Vitamin D Levels?

Deficient- Less than 25 nmol/l

Insufficient- 25-50 nmol/l

Sufficient- 50/75 nmol/l

Optimal- Greater than 75 nmol/l

In the UK, research showed that more than half of the adult population have insufficient levels of vitamin D and that 16% have deficient levels during the winter.


What is the recommended intake of Vitamin D? 

The most common recommendation for anyone who may be vitamin D deficient is 400 IU (10 micrograms). Take over the counter vitamin D and vitamin D3 supplements to improve your vitamin D levels. These are easily found in local chemists, pharmacists or even going to your GP and these vary depending on the type of brand.

Vitamin D intakeVitamin D Levels


What is Vitamin D3?

Vitamin D3 is produced naturally in the skin when it is exposed to sunlight. It transforms into a hormone within the body. In this form, it is circulated in the bloodstream to help in the absorption of calcium and phosphorus that is received from digested food sources. Almost 99% of your vitamin D supply is used for regulating the calcium in your body; the remaining part is utilised for strengthening the immune system and maintaining muscle strength.

Vitamin D3 comes from the sun, food and supplements. The active ingredient contained in D3 is cholecalciferol which is a type of Vitamin D made by the skin, found in some foods and taken as a dietary supplement. Vitamin D3 is one of the most effective methods of vitamin D. Research suggests that Vitamin D3 is approximately 85% better in raising and maintaining Vitamin D concentrations in the body and produces 200-300% greater storage of Vitamin D than vitamin D2.