What is vitamin D deficiency?

What is vitamin D?

Vitamin D is a prohormone which is produced when UV from sunlight acts on the skin, which is why vitamin D is often referred to as the “sunshine vitamin”. Vitamin D is then activated in a two-step process, first by the liver and then by the kidneys resulting in the active form.

However, it’s not always possible to get enough from the sun. In a northern climate, winter sun is not sufficient for most people to make enough vitamin D. 

Activated vitamin D is a hormone that is responsible for controlling calcium in the blood which keeps your bones, muscles and teeth healthy and strong. Beyond that active vitamin D interacts with most cells in your body and probably plays a crucial role in keeping you healthy. We go into a lot more detail on vitamin D and why it’s key to our health in our previous blog post.

There are two main dietary forms of vitamin D. The first is vitamin D2 (ergocalciferol) which is primarily obtained from plant sources, and the second is D3 (cholecalciferol) which comes from animal sources. But dietary supply of Vitamin D is also not usually sufficient on its own to keep levels optimal.

• The current NHS recommendation for prevention of deficiency is 400 international units (IU) daily for all adults from October to March.

• In the absence of testing and during the winter months, a good starting point for healthy individuals is likely to be somewhere between 400IU (10 micrograms) and 2000IU (50 micrograms).

• The Tolerable Upper intake level (UL) is 4000 IU daily, which is the maximum level that’s considered to be safe.

If required, supplements can be taken to ensure that your body receives plenty of vitamin D, which can help prevent you from developing a deficiency. When we take vitamin D supplements, it’s usually taken as vitamin D3 (or plant-based vitamin D2).

What is vitamin D deficiency?

Having low levels of vitamin D is very common, especially during winter when there’s less sunlight available. A blood test is the most reliable method to determine whether you have a vitamin D deficiency, and your doctor will inform you on supplements you can take to boost your levels. As expert opinion tends to differ, the ranges for optimal vitamin D levels aren’t clearly defined. But, there is general medical agreement that people with less than 30 nmol/L are deficient, and while the right amount will vary from person to person, the suggested optimum range is somewhere between 75 – 150 nmol/L.

What are the signs of a vitamin D deficiency?

A vitamin D deficiency can present differently from person to person. Depending on how significant the deficiency is, some individuals may display no symptoms at all. Children with a severe deficiency may go on to develop rickets, so if they display any of the following symptoms, or are at risk of developing a vitamin D deficiency, always speak to your doctor.

Some of the main symptoms of rickets in children include:

• Painful bones – This may result in a child waddling, or they may be more reluctant to walk.

• Skeletal deformities – A child may have thicker ankles, wrists and knees, bowed legs, a soft skull, or in rare cases, bending of the spine.

• Dental issues – Teeth may be slower to come through, tooth enamel may be weak, and the child may have more cavities.

• Poor growth – The child may be shorter than average if their skeleton doesn’t develop as it should.

• Fragile bones – Bones may be weaker and might be more susceptible to fractures in serious cases.

Adults may display similar symptoms, including bone pain, fragile bones that are susceptible to fractures, and weak muscles, which can suggest osteomalacia.

For more information on the signs and symptoms of vitamin D deficiency, head over to our previous article. 

What are the risk factors for vitamin D deficiency?

Certain factors may increase your risk of developing a vitamin D deficiency, including:

• Ethnicity – If you have darker skin – for example you have an African, African-Caribbean or south Asian background – you may need to spend longer in the sun to produce the same amount of vitamin D as someone with lighter skin.

• Sun exposure -How often you expose your skin to sunlight will affect how much vitamin D your body is able to produce. The amount of clothing you cover your skin with, the time of day you work, how long you spend outdoors, and the area you live in can all have an impact.

• Genetics– Some people are genetically at risk of having lower levels of vitamin D. Taking a DNA test can reveal whether this applies to you.

• Age – The older you get, the less vitamin D your body produces. Therefore, older individuals are more at risk of developing a vitamin D deficiency. Plus, decreased mobility may result in less time spent outside.

• Obesity– Obese individuals, or those with an overweight BMI, may have lower levels of vitamin D. Although this idea is debated by clinicians, you may require a higher dosage of vitamin D supplements if you are overweight.

• Low-fat diets – Vitamin D is a fat-soluble vitamin, which means that your body can only absorb it when consuming fat. Therefore, low-fat diets may increase your likelihood of developing a vitamin D deficiency.

• Pregnancy and breastfeeding– When you’re pregnant, this places additional strain on the body, meaning that you may be at risk of developing a deficiency. If you’re breastfeeding, your breast milk may not contain sufficient levels of vitamin D, which could impact your baby’s development. If you plan on taking vitamin D supplements whilst pregnant or breastfeeding, you should always consult your doctor first.

• Taking certain medications– Certain medications, such as steroids and antiepileptic drugs, can increase the risk of developing a vitamin D deficiency.

• Certain medical conditions – Medical conditions such as Crohn’s disease can impair the body’s ability to digest and absorb nutrients as a result of poor bile production. This can lead to a deficiency.

• Kidney and liver disease– If your liver or kidneys are impaired, this can affect your body’s ability to produce vitamin D. If this applies to you, you may be prescribed an alternative form of vitamin D.

Treating a vitamin D deficiency

If you suspect that you have a vitamin D deficiency, it’s important that you book a doctor’s appointment to avoid any future complications. They will advise you on the best course of action to take, which will likely involve taking vitamin D supplements; the dose will range depending on the severity of your deficiency. In less extreme cases, you may be encouraged to eat more foods that are rich in vitamin D, and they may also recommend you spend more time outside.

With the Evergreen Life app, you can take the vitamin D check to track your wellbeing and also receive tips on how to improve other areas such as your sleep and happiness. Download the app and take your available questionnaires to start your wellness journey, and you can also choose to record your vitamin D levels.

Reviewed by Anna Keeble – Head of Content

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