Answering the Question: Which vitamin do most people lack in the winter?

October 5, 2025 •

4 min read

According to the Cleveland Clinic, approximately 1 billion people worldwide have a vitamin D deficiency, with levels often plummeting during the winter months. This widespread issue answers the question: Which vitamin do most people lack in the winter?

Quick Summary

Most individuals face lower vitamin D levels in winter due to limited sun exposure. This article explains the causes, recognizes symptoms of deficiency, and outlines effective strategies for maintaining optimal levels through nutrition and supplementation.

Key Points

Vitamin D is the most common winter deficiency: Due to limited sunlight, Vitamin D levels naturally drop in winter, affecting a significant portion of the population.
Limited sunlight is the main cause: Shorter days, weaker sun intensity, and spending more time indoors prevents the body from producing enough Vitamin D naturally.
Symptoms include fatigue and mood changes: Persistent tiredness, bone pain, weakened immunity, and mood fluctuations like SAD are common signs of deficiency.
Other nutrients also matter: While Vitamin D is key, deficiencies in Vitamin C, B vitamins, and iron can also occur due to dietary shifts in winter.
Boosting levels requires a multi-pronged approach: Combining dietary sources (fatty fish, fortified foods), safe sun exposure, and doctor-approved supplements is the most effective strategy.
Dietary changes are crucial: Incorporating nutrient-rich winter foods like root vegetables, leafy greens, and oily fish supports overall health and immunity.
Consult a professional: For an accurate diagnosis and personalized guidance on supplementation, it is important to talk to a healthcare provider.

The Winter's Primary Deficiency: The 'Sunshine Vitamin'

While our bodies require a host of nutrients, one stands out as a prevalent issue during the colder, darker months: Vitamin D. Commonly known as the “sunshine vitamin,” our body produces the majority of its Vitamin D when our skin is exposed to sunlight. However, winter presents a perfect storm for deficiency. Shorter daylight hours, less intense sun, and spending more time indoors mean our skin has fewer opportunities to synthesize this crucial nutrient. Living at higher latitudes exacerbates this problem, as the sun's angle and intensity during winter are often insufficient for effective Vitamin D production.

Beyond its role in calcium absorption for healthy bones, Vitamin D also significantly impacts our immune system and mood. Low levels are linked to a higher susceptibility to infections and conditions like Seasonal Affective Disorder (SAD), which can manifest as fatigue and low mood. A staggering study of adults in Poland, for instance, found that over 84% were Vitamin D deficient during late winter and early spring.

Recognizing the Symptoms of Low Vitamin D

Symptoms of a Vitamin D deficiency can be subtle at first and might be mistaken for general winter blues. However, if they persist, it is important to consider a check-up with a healthcare professional. Signs to look out for include:

Fatigue and Weakness: Persistent tiredness, even after a full night's sleep, is a common symptom.
Bone and Muscle Pain: Chronic pain in bones, especially the back, as well as muscle weakness or cramps, can occur because Vitamin D is critical for calcium absorption.
Mood Changes: Lower levels are linked to mood swings and depression, particularly SAD, due to Vitamin D's effect on serotonin levels.
Weakened Immunity: Frequent colds, flu, and other infections might indicate your immune system is not functioning optimally.
Hair Loss: While less common, some studies have linked Vitamin D deficiency to hair loss.

Other Important Winter Nutrients to Watch

While Vitamin D is the most widely discussed winter deficiency, other nutrients can also be compromised during the colder months due to changes in diet and lifestyle. These include:

Vitamin C: Many people reduce their intake of fresh fruits and vegetables during winter, which are the best sources of Vitamin C. This vitamin is essential for immune function, wound healing, and can reduce the severity of colds. Good winter sources include citrus fruits, bell peppers, broccoli, and kiwi.
B Vitamins (especially B12): B vitamins help the body convert food into energy, and a deficiency can contribute to tiredness and fatigue. Vitamin B12, often found in animal products, helps maintain nerve and blood cell health and can combat fatigue. This is especially important for vegetarians and vegans who may need fortified foods or supplements.
Iron: This mineral is vital for producing hemoglobin, which carries oxygen in the blood. Fatigue, cold hands and feet, and weakness can be signs of low iron. While most common in red meat, other sources include lentils, beans, and leafy greens.

Practical Tips to Ensure Adequate Winter Nutrition

To combat the effects of the season, consider incorporating these strategies into your routine:

Eat a varied diet: Include a range of seasonal produce like root vegetables (carrots, sweet potatoes), dark leafy greens (spinach, kale), and citrus fruits. Add fatty fish like salmon or mackerel a few times a week.
Spend time outdoors: Even on cloudy winter days, a short walk at midday can provide some beneficial sun exposure. Just 10-30 minutes can make a difference, depending on your location and skin type.
Opt for fortified foods: Look for milk (dairy and plant-based), orange juice, and cereals that are fortified with Vitamin D to help bridge the nutritional gap.
Consider a supplement: For those with confirmed deficiencies or limited access to sunlight and fortified foods, a Vitamin D supplement (ideally D3) is often recommended. A healthcare provider can help determine the correct dosage.
Address other nutrient needs: If you're feeling a lack of energy, discuss your diet with a professional to ensure you're getting sufficient Vitamin C, B vitamins, and iron, possibly from supplements or dietary adjustments.

Winter Vitamin Comparison Table


Nutrient	Primary Function	Why Lacking in Winter	Best Winter Sources
Vitamin D	Calcium absorption, bone health, immune function, mood regulation	Reduced sun exposure, weaker sunlight	Fatty fish (salmon, tuna), fortified milk/cereals, mushrooms, egg yolks
Vitamin C	Immune system support, antioxidant, collagen synthesis	Reduced intake of fresh produce, sensitivity to heat during cooking	Citrus fruits, bell peppers, broccoli, strawberries, kiwi, potatoes
Vitamin B12	Red blood cell formation, energy production, neurological function	Diet changes (especially in vegetarians/vegans), poor absorption	Red meat, fish, fortified cereals, legumes, dairy products

Conclusion: A Proactive Approach to Winter Health

While Vitamin D is the most prominent vitamin people lack in the winter, focusing on overall nutritional health is key to thriving through the colder months. Limited sunlight and seasonal changes in diet can create deficiencies that impact energy levels, immunity, and mental well-being. By being proactive—incorporating Vitamin D-rich and fortified foods, taking supplements under medical guidance, and making time for outdoor light—you can support your body's needs. A balanced diet featuring a variety of seasonal produce and hearty whole foods provides the essential vitamins and minerals your body requires to stay strong, healthy, and resilient against winter-related challenges. For more detailed information on Vitamin D recommendations, consult an authoritative source like the NHS guide on Vitamin D.

Note: Always consult with a healthcare professional before starting any new supplement regimen, especially if you have underlying health conditions or are pregnant.

Frequently Asked Questions

Vitamin D deficiency is a condition where the body does not have enough vitamin D. It is more common in winter because the body produces most of its Vitamin D from sun exposure. Reduced sunlight hours, weaker sun rays, and more time spent indoors during winter significantly decrease the body's natural Vitamin D production.

Symptoms of low vitamin D can include persistent fatigue and low energy, bone and joint pain, muscle weakness, frequent infections, and mood changes like depression or Seasonal Affective Disorder (SAD).

Even in winter, try to get 10-30 minutes of sun exposure on your face and arms, ideally at midday when the sun is strongest. However, depending on your location and skin type, sun exposure alone may not be enough, and it should be balanced with skin cancer risk.

Few foods naturally contain high levels of vitamin D, but good sources include fatty fish (salmon, tuna), fish liver oils, egg yolks, and mushrooms exposed to UV light. Many foods like milk, cereals, and orange juice are also fortified with vitamin D.

Government health bodies, such as the NHS, often advise that everyone should consider taking a daily vitamin D supplement during the autumn and winter months, as it's difficult to get enough from food alone during this period. It is best to consult a healthcare provider for personalized advice.

Yes. Due to dietary changes, you might also be deficient in Vitamin C (found in citrus and berries), B vitamins (for energy), and iron (for oxygen transport). A varied diet with plenty of seasonal vegetables can help address these needs.

A simple blood test can measure the level of vitamins in your blood. You can speak to a healthcare professional, who can assess your symptoms and order a test if necessary.