What Vitamin Should You Take If You Don't Get Sun? The Answer is Vitamin D

December 31, 2025 •

4 min read

It is estimated that around 50% of the global population has a vitamin D deficiency, primarily because sunlight is the most natural source. While the sun is often called the "sunshine vitamin," those who are indoors, live in certain climates, or have darker skin tones must seek alternative sources.

Quick Summary

This article explores the critical role of vitamin D in the body and details how to supplement your intake through diet, fortified foods, and specifically, vitamin D3 supplements, to combat low levels caused by limited sun exposure.

Key Points

The essential vitamin: If you do not get sun, the most important vitamin to take is Vitamin D to support bone health, immune function, and overall well-being.
Choose Vitamin D3: The D3 form (cholecalciferol) is more effective at raising and sustaining blood vitamin D levels than D2.
Supplements are a reliable option: Because few foods naturally contain significant vitamin D, supplements are often the most effective way to ensure adequate intake for those with limited sun exposure.
Incorporate fortified foods: Boost your intake by consuming foods like fortified milk, cereals, and orange juice, which have added vitamin D.
Consult a healthcare professional: Before starting supplementation, it is best to speak with a doctor to determine the right dosage for your needs, especially if you have a known deficiency.
Be mindful of the seasons and geography: Individuals in northern latitudes, or during winter months, are particularly at risk of deficiency due to reduced sun intensity.
Dietary sources can help: Include fatty fish, beef liver, and egg yolks in your diet to naturally increase your vitamin D, though it may not be enough on its own.

Why Vitamin D is Crucial for Your Health

Vitamin D is a fat-soluble vitamin that plays an essential role in numerous bodily functions, far beyond just bone health. It is integral to the absorption of calcium and phosphorus, which are vital for maintaining strong, healthy bones and teeth. Without adequate levels, the body's ability to absorb these minerals decreases, which can lead to weakened bones over time, increasing the risk of conditions like osteoporosis in adults and rickets in children.

Beyond skeletal health, vitamin D is also involved in the function of the immune system, helping the body fight off infections. Research suggests a link between low vitamin D levels and an increased risk of certain autoimmune diseases. Additionally, it supports nerve and muscle function and has been studied for its potential effects on mental health, with some studies showing a correlation between low vitamin D and symptoms of depression.

Natural vs. Supplemental Sources of Vitamin D

For most people, the body's primary method of producing vitamin D is through direct exposure to sunlight. The skin synthesizes vitamin D3 when exposed to ultraviolet B (UVB) rays. However, factors such as geographic location, time of year, use of sunscreen, and skin pigmentation can all limit this production. For those who don't get enough sun, including during the winter months, other sources become essential. Food sources containing vitamin D are relatively limited, making supplementation an important alternative.

Food Sources of Vitamin D

While food alone is unlikely to provide sufficient vitamin D, especially without sun exposure, incorporating these items into your diet can help boost your levels.

Fatty Fish: Salmon, mackerel, sardines, and tuna are excellent sources of naturally occurring vitamin D.
Fortified Foods: Many everyday foods are enriched with vitamin D. Look for fortified milk (dairy and plant-based), certain breakfast cereals, orange juice, and yogurt.
Egg Yolks and Beef Liver: These animal products contain smaller, but still beneficial, amounts of vitamin D.
Mushrooms: Some mushrooms, particularly those grown under UV light, can contain good amounts of vitamin D2.

Supplementation with Vitamin D

For those with limited sun exposure, taking a supplement is often the most reliable way to ensure adequate vitamin D intake. Vitamin D supplements are typically available in two forms: D2 (ergocalciferol) and D3 (cholecalciferol). Most experts and studies suggest that vitamin D3 is more effective at raising and maintaining blood levels. The typical recommended daily allowance for adults ranges from 600-800 IU, though those with a confirmed deficiency may require a higher dosage as advised by a healthcare provider.

Vitamin D2 vs. D3 Supplements: A Comparison

When choosing a supplement, understanding the difference between the two main forms can be helpful. While both forms are absorbed by the body, they are sourced differently and have varying levels of efficacy.


Feature	Vitamin D2 (Ergocalciferol)	Vitamin D3 (Cholecalciferol)
Source	Produced from plant-based sources, such as fungi.	Typically derived from animal products, such as the lanolin in sheep's wool, but vegan D3 from lichen is available.
Efficacy	Less effective at raising and sustaining blood vitamin D levels compared to D3.	Considered more effective at increasing blood concentrations of vitamin D.
Availability	Prescription-strength doses are available, and some is in fortified foods.	Widely available over-the-counter in various dosages.
Suitability	A vegan-friendly option, though less potent than D3.	The preferred choice for most people, including many doctors, due to its higher potency and effectiveness.

Conclusion

If you find yourself with limited sun exposure, the vitamin you should take is unequivocally vitamin D. Maintaining adequate levels is vital for bone health, immune function, and overall well-being. While dietary sources can help, supplementation, particularly with vitamin D3, is often the most effective method. It is always wise to consult with a healthcare professional before starting any new supplement regimen to determine the correct dosage for your individual needs. The risk of deficiency is high for those with minimal sunlight exposure, making proactive supplementation a crucial part of a healthy lifestyle.

For more detailed information on vitamin D supplementation and deficiency risks, consult the Harvard T.H. Chan School of Public Health.

How to Supplement Your Vitamin D Intake

Assess your lifestyle: Consider your location, sun exposure habits, and skin type to determine your risk of deficiency. People living farther from the equator or with darker skin need more consideration.
Increase dietary sources: Incorporate foods like fatty fish, fortified dairy or plant-based milk, and eggs into your meals to naturally boost your intake.
Choose the right supplement: A vitamin D3 supplement is generally recommended for optimal absorption and effectiveness.
Determine dosage with a professional: Consult a doctor or registered dietitian to find a daily dose that is appropriate for your age and specific health needs.
Consider a blood test: A healthcare provider can perform a blood test to check your current vitamin D levels, providing clarity on whether you need to supplement.

Practical Tips for Getting Enough Vitamin D

Combine sun and supplements safely: If you have limited access to sun, use supplements consistently, and when you do get sun, follow safe exposure guidelines.
Mind the seasons: Be especially vigilant about supplementation during autumn and winter, when UVB rays are weaker.
Pair with a meal: Since vitamin D is fat-soluble, taking your supplement with a meal containing healthy fats can enhance absorption.
Prioritize fortified foods: Make a habit of checking nutrition labels and choosing products fortified with vitamin D to add extra protection to your diet.

Frequently Asked Questions

A vitamin D deficiency can lead to weak bones, increasing the risk of conditions like osteoporosis in adults and rickets in children. Low levels can also negatively impact the immune system, leading to higher rates of infection, and can contribute to feelings of fatigue or depression.

No, you cannot. Glass windows block the UVB rays from the sun that your skin needs to produce vitamin D. To get it naturally, you need direct skin exposure to sunlight outdoors.

While the sun is the most natural source, supplements are a safer and more reliable option for those with limited sun exposure. Relying solely on sunlight for vitamin D can increase the risk of skin damage and cancer, whereas supplements offer a controlled dosage without this risk.

The recommended daily amount varies by age, but for most adults, it's typically between 600 and 800 International Units (IU). However, a doctor may recommend a different dosage based on a blood test revealing your current vitamin D levels.

Vitamin D2 comes from plant sources and is less effective at raising and maintaining blood vitamin D levels than vitamin D3. Vitamin D3 is produced in the skin and found in animal products, and it is the form most commonly recommended for supplementation due to its higher potency.

Few foods are naturally rich in vitamin D, but some good sources include fatty fish like salmon, fortified milk and cereals, and egg yolks. For most people, diet alone is insufficient to meet their needs without adequate sun exposure.

People who are not often outdoors, live in northern climates, have darker skin, are older, or have conditions affecting fat absorption (as vitamin D is fat-soluble) are at a higher risk of deficiency.