As the days grow shorter and sunlight becomes scarce, many people start to feel more tired, low in energy, or even run down. While colder weather and darker mornings play a role, there’s another important factor often overlooked during winter: Vitamin D.
Often called the “sunshine vitamin,” Vitamin D is essential for overall health, and winter is when deficiency is most likely to occur. Understanding why this nutrient matters—and how to maintain healthy levels—can make a noticeable difference to your wellbeing during the colder months.
What Is Vitamin D?
Vitamin D is a fat-soluble vitamin that plays a vital role in several key bodily functions. Unlike most vitamins, your body can produce Vitamin D when your skin is exposed to sunlight. However, when sunlight exposure drops (as it does in winter), maintaining adequate levels becomes more challenging.
Vitamin D exists in two main forms:
- Vitamin D2 (ergocalciferol) – found in some plant-based foods
- Vitamin D3 (cholecalciferol) – produced by the skin and found in animal-based foods
Vitamin D3 is generally considered more effective at raising and maintaining healthy Vitamin D levels.
Why Vitamin D Is So Important
1. Supports Bone and Muscle Health
Vitamin D helps the body absorb calcium and phosphorus—two minerals essential for strong bones and teeth. Without enough Vitamin D, bones can become weak or brittle over time, increasing the risk of fractures and conditions such as osteoporosis.
Muscle strength also relies on adequate Vitamin D levels, which is especially important during winter when people may already be less active.
2. Boosts Immune Function
Your immune system depends on Vitamin D to function effectively. Research suggests that low Vitamin D levels may be linked to increased susceptibility to infections, particularly respiratory illnesses—which tend to peak during winter months.
Maintaining healthy Vitamin D levels can help your immune system respond better when you need it most.
3. Supports Mood and Mental Wellbeing
Seasonal changes in sunlight exposure can affect mood, and Vitamin D plays a role in regulating chemicals in the brain linked to mood balance. Low levels have been associated with feelings of low mood and seasonal blues, making winter an especially critical time to monitor intake.
4. Contributes to Overall Energy Levels
Persistent fatigue is a common complaint during winter. While many factors can contribute, Vitamin D deficiency is often linked to low energy levels and tiredness.
Why Winter Increases the Risk of Deficiency
During autumn and winter, the sun sits lower in the sky, especially in northern regions. This means:
- UVB rays are weaker
- Skin produces far less Vitamin D
- People spend more time indoors and covered up
As a result, even those who maintain healthy levels in summer can become deficient by winter.
Signs You Might Be Low in Vitamin D
Vitamin D deficiency isn’t always obvious, but common symptoms may include:
- Frequent colds or infections
- Fatigue or low energy
- Muscle aches or weakness
- Joint pain
- Low mood
If symptoms persist, a healthcare professional can confirm levels through a blood test.
Dietary Sources of Vitamin D
While food alone often isn’t enough to meet daily needs, including Vitamin D-rich foods in your diet can help:
- Fatty fish (salmon, mackerel, sardines)
- Egg yolks
- Liver
- Fortified foods (such as some plant milks, cereals, and spreads)
Because natural food sources are limited, many people struggle to meet requirements through diet alone—particularly in winter.
Supplementation During Winter
Health authorities in many countries recommend Vitamin D supplementation during autumn and winter months, especially for:
- People with limited sun exposure
- Older adults
- Individuals with darker skin tones
- Those who spend most of their time indoors
Typical daily recommendations range from 400–1000 IU, though individual needs may vary. Always follow guidance from a healthcare professional.
Simple Tips to Maintain Healthy Levels
- Spend time outdoors when daylight allows
- Include Vitamin D-rich foods regularly
- Consider a daily supplement during winter
- Maintain a balanced diet with adequate calcium