The great influence of vitamin D on your health
Winter has begun again, and the sun is much less powerful. You start the day in the dark and end it in the dark. No wonder you feel a bit sluggish. During these dark months, many people don't produce enough vitamin D, and you notice this sooner than you think. Fatigue, lowered immunity, low mood, or muscle pain can all be signs of a deficiency. Vitamin D isn't called the sunshine vitamin for nothing, as it plays a major role in how we feel and function.
Vitamin D is one of the most important natural sources of health. Of all vitamins, it's the only one the body can produce naturally. All we need to do is expose our skin to the sun, which has been the case for millions of years. And that's precisely the problem, because many people now consider the sun a health hazard. The sun provides the warmth that makes life on Earth possible. Almost all living things need sunlight to survive.
What is vitamin D and how is it produced?
Vitamin D isn't actually a true vitamin, but a fat-soluble, hormone-like substance that our bodies can produce naturally under the influence of sunlight (UVB radiation). When sunlight hits our skin, our bodies convert cholesterol into vitamin D3. This active form of vitamin D helps with numerous processes in the body, especially in bones, muscles, and the immune system.
In the summer, we often build up a supply. In the winter, especially in the Netherlands, the sun is too low to provide sufficient UVB radiation. That's why many people experience a deficiency in the fall and winter.
How does vitamin D work with calcium and vitamin K2?
Vitamin D works closely with calcium and vitamin K2, keeping our bodies strong and healthy. When there's enough vitamin D, it helps us better absorb calcium from food. Calcium is a mineral essential for strong bones and teeth. But that's not the end of the story. Vitamin K2 ensures that the absorbed calcium reaches the right places in the body. In the bones, it provides strength and control. However, it doesn't belong in the blood vessels, where it can actually cause damage. Without enough K2, a high dose of vitamin D can even be counterproductive. It's the collaboration between vitamin D, vitamin K2, and calcium that ensures your body remains balanced and functions optimally. Our supplement (referred to as vitamin D3 + K2) uses vitamin D3 in combination with K2.
Vitamin D in food
There are two forms of vitamin D: D2 and D3. Vitamin D2 is primarily found in plant products and mushrooms, while D3 comes primarily from animal sources and is produced in the skin under the influence of sunlight. D3 is generally better absorbed and more effectively converted into the active form that the body uses.
Although sunlight is the main source of vitamin D3, you can also get a small amount through food. Oily fish, such as anchovies, sardines, herring, and mackerel, contain relatively high levels of vitamin D. Eggs, especially the yolk, and liver or cod liver oil also contain it. However, it remains difficult to get enough through food alone, especially during the winter months when sunlight is weak. Therefore, taking a supplement is often recommended, especially for people at increased risk of deficiency.
How Vitamin D Affects Our Cells
In the body, vitamin D is converted into an active form that binds to a receptor (a kind of switch found in many different cells). Once this switch is turned on, it controls the activity of certain genes. This allows cells to produce more proteins, for example, that are important for calcium absorption, but also substances that regulate the immune system or inhibit inflammation. In this way, vitamin D directly influences the way our cells function and work together.
The benefits of vitamin D
Vitamin D is essential for our bodies. It helps with calcium absorption, keeping bones and teeth strong. It also supports our muscles: sufficient vitamin D contributes to strength and balance. Furthermore, it supports the functioning of the immune system, which protects us from pathogens.
But vitamin D's role extends beyond bones, muscles, and immunity. A growing body of research shows that it can also influence our mood and may have a protective effect against low mood and depressive symptoms. Furthermore, there are indications that good vitamin D levels can reduce the risk of chronic conditions such as cardiovascular disease, cancer, and diabetes.
Who is at greater risk of vitamin D deficiency?
Vitamin D deficiency is particularly prevalent in groups with lower production or absorption. Older adults produce vitamin D less efficiently through the skin and also absorb it less effectively from food. People with darker skin have lower melanin metabolism in the skin with the same amount of sunlight. People who rarely spend time outdoors, wear opaque clothing, or consistently use sunscreen are also at greater risk. Reduced absorption can also occur with intestinal, liver, or kidney disorders. Furthermore, young children, pregnant women, and people who eat few foods rich in vitamin D are more likely to develop low vitamin D status.
Practical tips
- Get outside for 15–30 minutes every day with your face and hands uncovered (between 11:00 AM and 3:00 PM, when the sun is strong enough). Enjoy the sunshine! :)
- Eat oily fish 2-3 times a week.
- In winter, consider a vitamin D supplement of 25–75 µg per day, depending on your needs.
- Combine vitamin D3 with vitamin K2 for optimal absorption and balance.
- Have your blood values tested occasionally to know where you stand.
Book tips
- “Superhormone vitamin D” by Jörg Spitz
- “New light on vitamin D” by Gert Schuitemaker
