Many people know vitamin D as an essential nutrient for healthy bones. But vitamin D plays a much bigger role in our overall wellbeing, including immunity, mood and preventing chronic disease. 

Let’s take a look at why getting enough vitamin D is about more than just bone health.

What is vitamin D?

Vitamin D is one of the essential fat-soluble vitamins humans need to stay healthy.

Most of our vitamin D comes from cholesterol being converted into vitamin D when our skin is exposed to the sun. This is why you’ll often hear it referred to as ‘the sunshine vitamin’.

Unlike other vitamins, vitamin D acts as a steroid hormone in the body. It binds to receptors that can turn genes on or off, which can lead to changes in your body’s cells. 

There are two main forms of vitamin D – D2, or ergocalciferol, and D3, or cholecalciferol. D2 is found in some plants, mushrooms and yeasts. D3 is found in fatty fish and egg yolks. 

Of the two forms, vitamin D3 is almost twice as effective at raising vitamin D levels in the blood.

Why is vitamin D important for well-being?

There are numerous reasons why vitamin D is essential for your general health. Let’s have a closer look at some of the evidence-based benefits of getting enough vitamin D.

• Healthy bones. Vitamin D has a variety of effects on bone health. It promotes the absorption of calcium and phosphorus from the digestive tract. Studies suggest that good levels of vitamin D can protect against osteoporosis, falls and fractures.

• Reduced risk of chronic disease.  Low levels of vitamin D are associated with a higher risk of heart disease, diabetes, cancer, dementia and autoimmune conditions. Many of these conditions have elements of inflammation or immune involvement. 

Although more studies are needed to confirm vitamin D’s impact on these conditions, having sufficient vitamin D can reduce the risks.

Improved physical strength. As we age, we lose physical strength. This can often contribute to issues such as falls. But studies have shown that vitamin D can increase physical strength in both the upper and lower limbs.

Managing symptoms of depression. Sunshine can often make us feel more cheerful – and it turns out there might be a good reason. Studies have shown that vitamin D may ease symptoms for some people with clinical depression.

Longer life expectancy. Vitamin D deficiency is linked to a reduction in overall life expectancy. Some studies suggest that vitamin D can reduce the risk of dying, which means it could help you to live a longer life.

How much vitamin D do we need?

This can depend on the individual. Factors such as chronic illness, skin colour and exposure to the sun can change a person’s risk of deficiency. The NHS recommends that adults in the UK consider taking a daily supplement with 10mcg (400IU) of vitamin D. 

However, this may not be a sufficient dose for those who are already deficient in vitamin D. Research suggests that 25mcg, or 1000IU, would bring 50% of the population’s vitamin D levels into a beneficial range for wellbeing. 50mcg, or 2000IU, would help nearly everyone reach optimal vitamin D levels.

Why we suggest taking vitamin D with vitamin K2

You might have heard that it’s best to take vitamin D with vitamin K2. This comes back to how too much vitamin D taken without vitamin K could increase the risk of heart disease and other chronic conditions.

One of the roles of vitamin D is to maintain calcium levels in the blood. It enhances the absorption of calcium from food. If there isn’t enough calcium in the foods you eat, vitamin D will draw on the calcium from your bones.

Although vitamin D maintains the blood levels of calcium, it doesn’t control where extra calcium ends up in the body. That is the role of vitamin K. Vitamin K promotes the accumulation of calcium in your bones and teeth. It also prevents calcium from accumulating in tissues such as blood vessels and the kidneys.

Excess calcium in blood vessels is believed to play a role in chronic diseases such as heart and kidney disease.

What does this have to do with vitamin D? Excess vitamin D can cause hypercalcaemia – extremely high levels of calcium in the blood. This is known to lead to calcium in the blood vessels, or BVC. BVC is one of the main underlying causes of heart disease.

Low vitamin K is associated with BVC. Research has shown that vitamin K can prevent blood vessels from calcifying in animal studies. Although there are limited studies in humans, people who eat a high amount of K2 in the diet have a reduced risk of BVC and heart disease.

So to summarise – excess vitamin D may cause blood vessels to calcify, but vitamin K may help to prevent this from occurring.

If that wasn’t reason enough, combining vitamin D and K2 may be beneficial in itself. The two vitamins have synergistic effects, meaning that they work as a team to support healthy bones.