Vitamin D: the sunshine vitamin

Sabina Muminović Last updated: 27 October 2023

You probably know that we need vitamin D for healthy bones. But do you know its other roles and that your genes can influence its optimal levels? It’s time you meet this important nutrient properly.

Vitamins are essential micronutrients – substances our bodies can’t produce but need in small quantities. Out of all the vitamins, vitamin D is perhaps the most intriguing, because our bodies can make it – with just a little help from the Sun!

In this article

What are the benefits of vitamin D?

Not many people know that the so-called sunshine vitamin is not even technically a vitamin, but rather a hormone, or specifically, its precursor – a prehormone.

It was first identified as a vitamin early in the 20th century but is now recognised as a prehormone due to its effects, which are stimulated by the same mechanisms as other steroid hormones. However, it does function as a vitamin, so the scientists let it stay among vitamins.

To produce vitamin D, our bodies need sunlight and one other component. Remember cholesterol, an important fat with many functions? It turns out one of them is helping make a vitamin.

Under the influence of UVB light, cholesterol in our skin is converted to previtamin D. We say previtamin because, at this point, it is still inactive and must undergo two changes in our liver and kidneys. Then it is ready to get to work and help our bodies maintain:

  • Strong bones: vitamin D promotes calcium absorption and ensures proper levels of calcium and phosphorus in your blood. Both minerals are crucial for bone mineralisation, ensuring strong bones and teeth.
  • Normal muscle function: ensures stability, muscle strength, and good physical performance.
  • Effective immune system: vitamin D activates your body’s T-cells, responsible for identifying and attacking pathogens.

Benefits of vitamin D


How can you tell you lack vitamin D? 

We now know that vitamin D is essential for our wellbeing. But which symptoms tell you might be lacking it?

Let’s take a look!

1. Getting sick often

Vitamin D interacts with the cells that are responsible for fighting off infections. So if you’re constantly getting sick and infected, it might be due to low vitamin D levels! Try adding it to your diet, while improving other habits affecting your immune system.

2. Fatigue and tiredness

Feeling tired?

There’s a lot of causes for feeling tired. A lot! Often overlooked, vitamin D deficiency may be one of them. Case studies have shown that very low blood levels can cause fatigue that has a severe negative effect on the quality of life.

3. Bone, joint, and back pain

We mentioned that vitamin D helps maintain strong bones by improving your body’s absorption of calcium. However, it also affects your bone and back pain!

4. Depression and mood swings

Depression along with extreme mood swings may also be a sign of vitamin D deficiency. Try taking supplements and keeping track of your general mood, wellbeing, and outlook on life! See if it helps regulate your mood swings and depression. If not, speak to your doctor about further steps.

You can try improving your outlook on life by discovering your predispositions for stress response and susceptibility, optimism, happiness, fear, and seasonal depression with our MyLifestyle DNA test. 

5. Impaired wound healing

Are your wounds healing too slow? Yup, it might be another sign your body is lacking vitamin D!

This vitamin increases the production of compounds crucial for forming new skin as part of the wound-healing process. It also controls inflammation and fights infection – all important for proper healing of your wounds.

Common symptoms of vitamin D deficiency

6. Hair loss

We often attribute hair loss to stress. Indeed, stress is a common cause of this symptom.

However, when hair loss is severe, it may result from a disease or nutrient deficiency. Hair loss in women has been linked to low vitamin D levels, though there is very little research on this to date.

7. Muscle pain, cramps, weakness

The causes of muscle pain are often difficult to pinpoint. There is a link between chronic pain and low blood levels of vitamin D, which may be due to the interaction between the vitamin and pain-sensing nerve cells.

Thinking you might have a vitamin D deficiency? You must speak to your doctor and get your blood levels measured! Knowing for sure your vitamin D blood levels are low, you can take actions to improve them.

Discover where vitamin D can be found and start incorporating these sources into your daily life.

Sources of vitamin D: Sun, food, and supplements

Sun is the best source of this nutrient. World Health Organization recommends exposing our arms and legs to sunshine for 5 to 15 minutes, between 10 a.m. and 3 p.m., 2–3 times a week. This ensures a sufficient amount of vitamin D.

You might not get enough vitamin D in winter if you live far from the equator, are overweight, older, or have dark skin. In those cases, you need to consider the alternatives for maintaining normal levels: food and supplements.

There is only a handful of foods containing vitamin D:

• oily fish (salmon, tuna, mackerel),
• dairy,
• egg yolk,
• and liver.

But there is an abundance of foods fortified with vitamin D (breakfast cereals, yoghurt). In the USA and Canada, for example, all milk is fortified with vitamin D!

There is also a wide range of dietary supplements to choose from – from fish oil capsules to vitamin D sprays.

Vitamin D promotes healthy skin

Not only does the sunshine vitamin do wonders for your bones, muscles, and immune system, it is also great for your skin! It regulates cell growth, reduces inflammation, and increases skin elasticity by stimulating collagen production. It also helps with many skin conditions such as eczema, psoriasis, acne, rosacea, etc.

But as you know, the Sun doesn’t only replenish your vitamin D reserves but can lead to severe skin damage. So make sure to use sunscreen, which should become your best friend during summer, and limit direct sun exposure to no more than half an hour between 11 a.m. and 3 p.m.

Your genes can help predict your level of vitamin D

Besides sun exposure and diet, there is a genetic component to how much vitamin D our bodies produce. Scientists have discovered three genes linked with vitamin D levels: GC, DHCR7, and CYP2R1.

Every second individual is predisposed to lack of vitamin D! Finding out if you are among them is easy with our DNA test, which analyses all three relevant genes and gives you personal recommendations based on your results.

We think about vitamin D more often during winter months when seeing the Sun is almost a special occasion, but our genes can contribute to an increased need for this nutrient.

Suppose you discover that you are genetically predisposed to lower vitamin D levels. In that case, you can now pay more attention to nutrition or even grab a supplement to make sure your bones – and entire body – stay healthy.

Woman sitting in front of a window and enjoying the sunlight

What about too much of it?

Many people are considered insufficient in vitamin D, but you can get too much of it as well! This most often occurs in people using vitamin D supplements. You can pay attention to specific side effects that indicate too much vitamin D. These are:

  • elevated blood calcium levels,
  • nausea,
  • poor appetite,
  • stomach pain,
  • constipation,
  • diarrhoea.

If your blood levels of vitamin D are way too high, vitamin D toxicity may occur. This is a very rare but severe condition, usually due to excessive long-term intake of the vitamin.

How much is too much?

The recommended dose of vitamin D varies by age and other factors. In general, consuming 400–800 IU (10–20 mcg) of vitamin D should meet the needs of 97–98% of all healthy people.

Trying to pinpoint a healthy vitamin D level is tricky!

Some of the leading epidemiologists and endocrinologists feel that we are over-screening for vitamin D deficiency and unnecessarily treating healthy individuals. So, while in 2011 the Endocrine Society issued a report recommending vitamin D levels of at least 30 ng/mL, the previously mentioned group of epidemiologists say a more appropriate cut-off for vitamin D deficiency would is much lower, at 12.5 ng/mL.

This controversy continues, with many articles and statements made to support one or the other guideline.

As the awareness surrounding vitamin D insufficiency increases, more vitamin D blood tests are being ordered. This leads to healthcare providers suggesting vitamin D supplementation and so-called overcorrection due to consistent overdosing. Overcorrection is thought to be one of the primary causes of vitamin D toxicity. Nonetheless, it is very rare, so don’t worry.

You would need to take extremely high doses of 50,000 IU (1,250 mcg) or more for some time, and overdosing on vitamin D from sunlight only is impossible!

You can see that vitamin D is about way more than just strong and healthy bones. Focus on adding it more to your life – while you can try incorporating some vitamin D-rich foods into your diet, the best way to get more is by simply going outside each day and soaking up the Sun!




Share this article on