Vitamin D in Danish Summers:
Do You Still Need Supplements?

When summer finally arrives in Denmark, many people feel a sense of relief. The days grow longer, the light stretches late into the evening, and it’s tempting to believe that a few months of sunshine will naturally restore our bodies after a long, dark winter. Vitamin D, often called the "sunshine vitamin," seems like something we can stop worrying about once June rolls around. But is that actually true?

The reality is more complicated. Despite the longer daylight hours, a surprising number of Danes still experience vitamin D deficiency during the summer months. Limited sun exposure, sunscreen use, indoor lifestyles, and even the angle of the sun itself play a role in how much vitamin D your body can produce — and it’s often not as much as you might think.

Let's take a closer look at why vitamin D is so important, whether the Danish summer is enough to meet your needs, and if supplements still have a place even when the sun is high in the sky.

Why Is Vitamin D So Important?

Vitamin D is crucial for many processes in your body. Its most famous role is helping you absorb calcium to build and maintain strong bones and teeth. But its influence goes much further than that. Vitamin D supports your immune system, muscle function, and mood regulation. Some research even links sufficient vitamin D levels to reduced risk of diseases like type 2 diabetes, depression, and certain cancers.

When your body doesn't get enough vitamin D, you might not notice symptoms immediately. Over time, though, deficiency can contribute to weaker bones, increased risk of fractures, muscle weakness, fatigue, low mood, and a weakened immune response. It’s not something you want to ignore, especially when the fix can be relatively simple.

Sunlight and Vitamin D Production: The Danish Reality

In theory, the body can produce all the vitamin D it needs when your skin is exposed to UVB rays from the sun. However, several factors limit how much vitamin D you can actually synthesize — even during the bright Danish summer.

First, there's the simple matter of latitude. Denmark lies relatively far north, and while the days are long in summer, the strength of UVB radiation is still not as high as in southern countries. The effective “vitamin D window” where sunlight is strong enough for production is actually quite narrow.

Second, there's how we live our lives. Most people spend large parts of the day indoors, working, studying, or engaging in indoor activities. Even when we do go outside, sunscreen use is heavily promoted — and for good reason, to prevent skin cancer — but sunscreen with a high SPF can reduce vitamin D synthesis in the skin by up to 95%.

Clothing also matters. Light dresses, long sleeves, hats — all can block UVB rays from reaching your skin. Even cloudy days, which are common in Denmark, cut down UVB exposure significantly.

Research from DTU Food Institute has shown that even during summer months, many Danes don’t reach optimal blood levels of vitamin D unless they intentionally expose skin to the midday sun several times a week without sunscreen — something few people actually do consistently.

How Much Vitamin D Do You Really Need?

Health authorities generally recommend that adults aim for around 10 micrograms of vitamin D per day, while older adults over 70 years, individuals with darker skin, or those at risk for deficiency may need up to 20 micrograms daily.

In blood measurements, optimal vitamin D levels are usually considered to be around 50 nmol/L (nanomoles per liter) or higher. Many Danes fall short of this, especially outside of high summer.

It's important to remember that vitamin D is a fat-soluble vitamin. This means your body can store it, especially during the sunnier months, and tap into those reserves during darker times. But you can only store so much, and if your levels never peak high enough in summer, you may enter autumn and winter already running low.

Can Diet Cover Your Needs?

Some foods naturally contain vitamin D, though the list is relatively short. Fatty fish like salmon, mackerel, and herring are the richest natural sources. Liver, egg yolks, and fortified foods like margarine and certain dairy products can also contribute.

The problem is that most people simply don’t eat enough of these foods to rely on diet alone. Danish dietary surveys consistently show low consumption of fatty fish, especially among younger people and the elderly.

Even if you eat fish twice a week as recommended, it's unlikely to be enough to fully meet your needs year-round without some sunlight or supplementation.

Sunscreen: A Blessing and a Barrier

It would be irresponsible to suggest skipping sunscreen. Protecting your skin from sunburn and reducing the risk of skin cancer is vital. However, it's also true that diligent sunscreen use significantly limits your skin's ability to produce vitamin D.

This creates a tricky balancing act. Health experts suggest brief, unprotected sun exposure — about 15–30 minutes a few times a week — on bare skin during midday hours to support vitamin D production. After that, sunscreen should be applied to prevent damage.

For many people, though, the reality is different. They may wear sunscreen all the time, seek shade, or simply not be outside enough, effectively closing the window for natural vitamin D production almost entirely.

Who Should Seriously Consider Supplementing — Even in Summer?

While everyone can benefit from mindful sun exposure and a vitamin D-rich diet, there are groups for whom supplementation makes particular sense even during the bright months.

If you spend most of your time indoors, have darker skin, wear covering clothing, are older, overweight, or suffer from conditions that affect fat absorption (like Crohn’s disease or celiac disease), you may not produce or absorb enough vitamin D naturally.

Even healthy individuals with active outdoor lifestyles sometimes find supplementation a safer and more reliable way to maintain consistent blood levels throughout the year.

Ultimately, it's about being realistic about your habits, skin type, and health status — not relying solely on sunshine optimism.

What Kind of Vitamin D Supplements Are Best?

When it comes to supplements, quality matters. Look for vitamin D3 (cholecalciferol), which is more effective at raising and maintaining vitamin D levels than D2 (ergocalciferol).

Supplements come in various forms — capsules, softgels, drops, sprays, and chewables. Choose what fits best into your routine. Consistency is more important than format.

For most healthy adults, a daily dose of 10–20 micrograms (400–800 IU) is sufficient for maintenance. Some might need higher doses if blood tests show deficiency, but it's important not to self-prescribe high doses long-term without medical advice, as too much vitamin D can lead to toxicity.

Is It Worth Testing Your Vitamin D Levels?

Testing isn't necessary for everyone, but if you suspect you’re at risk for deficiency or just want a clearer picture of your health, a simple blood test can measure your 25(OH)D levels. This can guide whether you need supplementation and how much.

Especially if you experience persistent fatigue, muscle weakness, bone pain, or low mood, checking your vitamin D status might be a smart move.

In Denmark, vitamin D testing isn't part of routine health checks unless there's a specific reason, but you can request it through your doctor or order private testing if needed.

Finding a Healthy Balance

Getting enough vitamin D is about balance — balancing sun exposure with skin protection, balancing diet with practical supplementation, balancing optimism with realism.

Danish summers are beautiful but fleeting. The light, while abundant, doesn't always deliver what your body needs without a conscious effort to get enough sun, the right foods, and possibly the right supplements.

In the end, vitamin D is not just a winter problem. It’s a year-round priority. Thinking critically about your personal habits and needs — not just the calendar — will help ensure your body stays strong, resilient, and ready for whatever the season brings.

Final Thoughts: Should You Take Vitamin D Supplements in Summer?

For many people in Denmark, the answer is yes — or at least, it's worth considering.

If you know you spend hours outdoors daily without sunscreen on some parts of your body, eat lots of fatty fish, and feel confident about your overall health, you might get away without supplements during the peak summer months.

But for most of us, a small, daily dose of vitamin D is an affordable and low-risk way to safeguard our health — even when the sun is shining.

It's not about fear or overmedicating. It's about giving your body the basic building blocks it needs to thrive. In that sense, a little capsule each day could be one of the simplest investments you can make in your future well-being.