What is vitamin D and why do we need it? The understanding nutrients series.

I thought that as we get into winter it would be a perfect time to cover vitamin D. 

Vitamin D is also called the sunshine vitamin as we can make it in our skin when exposed to sunlight. But as it’s winter and there’s no sun, (in the UK at least), vitamin D needs to be supplemented. This edition will cover why we need vitamin D and how much you should be having.

Check out all the other nutrients covered in the understanding nutrients series here. 

Roles of vitamin D: 

Vitamin D has many roles in the body, so I’ll touch on a few.

Bone and muscle health: the main thing you may know vitamin D for is helping to regulate the amount of calcium and phosphate in the body. This is linked to our bone health as these nutrients keep our bones healthy and strong. Vitamin D also has a part to play in muscle function and strength. 

Immune system: vitamin D also plays key roles in the immune system. It helps regulate the antimicrobial proteins in the gut which helps us fight infection. These antimicrobial proteins kill bacteria. It also increases the development of special white blood cells called macrophages. These cells engulf harmful microbes and stops them from making us ill.

Vitamin D does a lot for the body!

How much vitamin D should we be having? 

There are foods that contain vitamin D, but this typically isn’t enough for us to get all our needs. As I mentioned earlier, vitamin D can be made in the skin during the summer. But in winter months the UK doesn’t get enough sunlight for us to make enough vitamin D. Because of this, we need to supplement our vitamin D levels from October to March.

People with darker skin, people who spend a lot of time indoors, people who cover most of their skin, and pregnant/lactating people need to supplement all year round. As they’ll be at a higher risk of having low levels of vitamin D.

Adults should be having 10µg (or 400IU) daily to maintain their vitamin D levels. You can also get 'high strength' tablets that are 25µg (or 1000IU) and these are safe to take daily. Vitamin D3 is better absorbed by our bodies so opt for this if you can.

Vitamin D is a fat soluble vitamin meaning it's better absorbed with fats. So it's worth taking your supplement with a meal if possible.

Foods that contain vitamin D: 

Vitamin D from food can be poorly digested, so we can't totally rely on food sources to meet our requirements. But oily fish, egg yolks, and fortified cereals tend to be good sources of vitamin D for us.

• 100g of sardines has 3.27ug
• 100g of egg yolks has 10.8ug
• 100g of whole eggs (about 2 eggs) has 2.9ug
• 100g of pork loin has 1.2ug
• 100g of Rice Krispies (fortified with vitamin D) contain 8.4ug

What happens if we don’t get enough vitamin D?  

A lack of vitamin D can lead to a bone disease called osteomalacia. In children, this is called rickets.

Osteomalacia means your bones become softer and weaker. So, they can break more easily and bend. Symptoms can include pain felt in the bones and joints, muscle pain and weakness, and difficulty walking.

As rickets occurs in children, it affects bone development and can lead to bone deformities. The symptoms are similar to osteomalacia with bone pain, poor growth, and weak bones.

The treatment for both is the same – supplementing vitamin D and eating a diet that includes foods that are sources of vitamin D and calcium.

 

I hope this blog post has served as a reminder to take your vitamin D supplements! As you can see, it’s a crucial nutrient. I set an alarm on my phone to remind me to take mine each day.

Key points: 

• Vitamin D has many roles in the body including: maintaining our bone health, helping muscle function, and supporting the immune system.
• We need 10ug (micrograms) of vitamin D daily. People in the UK should supplement this in the winter months.
• Food sources of vitamin D include eggs, fortified breakfast cereals, and red meat.
• A deficiency in vitamin D leads to weak and soft bones. This is called rickets in children and osteomalacia in adults. It’s treated with vitamin D supplementation.

I hope you enjoyed this post! I’d love to hear your thoughts in the comments below.

Bye for now! 👋

References:

https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7019735/

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/743790/Dietary_Reference_Values_-_A_Guide__1991_.pdf

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/537616/SACN_Vitamin_D_and_Health_report.pdf

https://www.nhs.uk/conditions/rickets-and-osteomalacia/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5643801/