What is Vitamin D?
Vitamin D is essential for so many reasons, playing a vital role in bone health, immune function and overall health and wellbeing. But over half of us don’t get enough Vitamin D - and perhaps there’s more to it than just the weather! (source)
In this article, we’re looking at:
The role that Vitamin D plays in the body
Types of Vitamin D deficiencies
Signs and symptoms of Vitamin D deficiency & the causes
How much Vitamin D we need
Types of Vitamin D supplements
Foods that help with Vitamin D levels
Why do we need Vitamin D?
Vitamin D is essential, playing a key role in many bodily functions, including:
- Bone Health: Vitamin D enhances calcium absorption, which helps to reduce the risk of osteoporosis and fractures.
- Immune Support: Vitamin D helps to fight infections, reducing inflammation and protecting against illness.
- Mood Regulation: some studies such as this one have found a correlation between Vitamin D and wellbeing, noting ‘symptoms related to depression and Vitamin D deficiency’, which were improved by achieving higher levels of the vitamin in the body.
- Muscle Function: Vitamin D supports muscle strength and works to reduce the risk of falls in older adults.
What are the types of Vitamin D deficiency?
There are three categories of Vitamin D deficiency:
- A mild Deficiency doesn’t always have symptoms associated, but some could experience mild fatigue or muscle weakness.
- A moderate Deficiency will have more pronounced symptoms, which could include bone pain. You might also find you’re more susceptible to illness or infections too.
- A severe Deficiency can lead to serious conditions - such as rickets in children (a codition affecting bone development) and osteomalacia in adults.
What are the signs and symptoms of Vitamin D deficiency?
It's easy to miss the signs and symptoms of a Vitamin D deficiency, or to assume that what you’re experiencing is down to something else - and they can vary from person to person too. Most common symptoms of low Vitamin D include:
- Fatigue and tiredness
- Bone and muscle pain
- Frequent illnesses or infections
- Depression or mood changes
- Hair loss
- Impaired wound healing
If you’re concerned about how much Vitamin D you’re getting, speak to your GP for advice, especially if you’re experiencing any of these symptoms. Read more about the signs and symptoms of Vitamin D deficiency.
What causes low Vitamin D?
Think you might be low in Vitamin D, and wondering what on earth caused it? You’re not alone.
Low Vitamin D levels can be caused by various factors:
- Limited exposure to the sun: it’s official, bad weather is bad for us! Lack of outdoor activity or covering up too much can hinder vitamin D synthesis, keeping levels low and exacerbating symptoms.
- Poor Diet: Not consuming enough foods rich in vitamin D.
- Medical Conditions: some conditions can impair nutrient absorption.
- Obesity: being overweight doesn’t help, as excess fat can interfere with vitamin D utilisation in the body.
- Pregnancy and breastfeeding: an increased demand for nutrients can lead to deficiencies, especially if your diet is low in Vitamin D rich foods
Read more about what causes low Vitamin D.
It’s common to be deficient in Vitamin D and to also have low iron levels too - you can find out more about iron here.
What tests are available to check Vitamin D levels?
If you’re concerned about your Vitamin D levels, make an appointment to check in with your GP. Make a list of symptoms you’re experiencing, and be ready to answer questions on your diet and lifestyle.
Your doctor is likely to recommend a blood test to measure your Vitamin D levels. You may also be advised to have a bone density test too.
How much Vitamin D do I need?
So how much Vitamin D do we need per day?
Vitamin D for Adults
Adults need enough vitamin D to maintain bone density, muscle strength, and immune function. The recommended daily intake for adults is 10mg per day - including pregnant and breastfeeding women (NHS).
Vitamin D for Teens
Teens need vitamin D for bone growth and hormonal balance. Again, the recommended daily dose according to the NHS is 10mg per day.
Vitamin D for Pregnancy
Pregnant women need enough vitamin D for foetal bone development, as well as for their own health and wellbeing. The recommended dose for pregnant women remains the same, but according to the World Health Organisation (WHO) it can be common for mums-to-be to experience Vitamin D deficiency. If you’re concerned, speak to your midwife and/ or GP for advice.
What types of Vitamin D supplements are available?
If your Vitamin D levels are low, your doctor might recommend you take a supplement. As with other supplements, these should be taken alongside a healthy and balanced diet, and not as a repayment. Speak to your doctor for advice before you take them.
The Vitamin D supplements your doctor might recommend include:
- Vitamin D2 (Ergocalciferol): found in plant-based sources and fortified foods.
- Vitamin D3 (Cholecalciferol): derived from animal sources or synthesised through sunlight exposure. This one is more effective at raising blood levels of vitamin D.
- Tablets, capsules, and gummies : available in different doses for easy consumption.
- Liquid drops and sprays: ideal if you struggle with swallowing pills.
- Prescription-strength supplements: Given under medical supervision for severe deficiency.
Vitamin D3 and K2
You might notice that some supplements pair Vitamin D3 with Vitamin K2. Vitamin K2 has bone and heart health benefits, and is found in animal based foods and cheese. When combined, Vitamin D3 K2 help the body to absorb calcium more easily and keeps bones healthy.
What are the side effects of Vitamin D supplements?
Vitamin D is essential, but there can be side effects when you take supplements. Speak to your GP if you’re concerned.
Common side effects can include:
- Nausea and vomiting
- Hypercalcemia (high calcium levels) - a condition which can weaken bones
- Kidney stones
- Weakness and confusion
- Heart arrhythmias - an irregular heartbeat
Do I need to take Vitamin D supplements in the summer?
So if we get Vitamin D through sunshine and supplements, do we still need to take supplements in the summer time?
According to the NHS, most people are able to make enough Vitamin D through sunlight and diet between late March up to the end of September. Many choose not to take a supplement during these months, but if you spend a lot of time indoors it might be an idea to take a supplement all year round.
Speak to your doctor for guidance, and make sure you don’t exceed the recommended dose.
Foods to help with Vitamin D deficiency
There are many ways that you can get enough Vitamin D through the foods you eat. Foods rich in Vitamin D include:
- Fatty fish: salmon, mackerel, tuna
- Cod liver oil
- Fortified dairy products: milk, cheese, yogurt
- Fortified cereals
- Orange juice
- Egg yolks
- Mushrooms: look for the ones that have been exposed to UV lights
The bottom line on Vitamin D
Vitamin D is essential for overall health, yet many people experience deficiency due to limited sun exposure, poor diet, or medical conditions. Small changes to diet, spending time outdoors, and taking appropriate supplements can help to maintain optimal levels.
