Where can we get vitamin D? A comprehensive guide to sources

October 18, 2025 •

3 min read

Approximately 1 in 5 adults in the UK may experience a vitamin D deficiency during winter and spring, highlighting the importance of understanding where can we get vitamin D?. This essential nutrient, vital for bone health and immune function, is primarily synthesized through sun exposure, though diet and supplements also play a crucial role.

Quick Summary

Vitamin D is primarily obtained from sun exposure, but diet and supplements are also key sources. Foods rich in vitamin D include fatty fish, egg yolks, and fortified products like milk and cereal. Supplements, especially D3, can help bridge the gap, particularly during winter or for at-risk groups.

Key Points

Sunlight is the primary source: The body synthesizes vitamin D (D3) from UVB exposure, but factors like location, skin tone, and season affect production.
Dietary sources include fatty fish and fortified foods: Excellent food sources include salmon, sardines, and egg yolks, while many dairy products and cereals are fortified.
Supplements offer a reliable alternative: For those with limited sun exposure or specific dietary needs, supplements, particularly the D3 form, provide a consistent and controlled dosage.
D3 is more effective than D2: Research indicates that vitamin D3 is more potent and maintains blood levels more effectively than vitamin D2.
Combine sources for optimal intake: A balanced approach involving safe sun exposure, dietary sources, and supplements is often the most effective strategy for maintaining healthy vitamin D levels.
Consult a healthcare provider for personalized advice: It is best to seek medical guidance for determining your specific needs and correct supplementation dosage.

Vitamin D is often referred to as the “sunshine vitamin,” as the body can produce it when the skin is exposed to ultraviolet B (UVB) rays from the sun. This is the most direct source for many, but various factors can impact how much vitamin D your body makes from sunlight, including geographic location, time of year, and skin tone. For optimal levels, a combination of sun exposure, diet, and supplements is often recommended.

The Sun: A Major Source of Vitamin D

Sunlight triggers the skin to convert a cholesterol compound into vitamin D3. This D3 is then processed by the liver and kidneys into the active form the body uses. Brief, regular sun exposure (around 5-30 minutes, 2-3 times per week) can often provide sufficient vitamin D for many individuals.

Factors Affecting Sun-Based Vitamin D Production

Several factors influence vitamin D synthesis from sunlight, including geographic location, skin pigmentation, time of day, and age. Additionally, sunscreen and clothing can block UVB rays and reduce vitamin D production.

Dietary Sources: From Foods and Fortification

When sun exposure is insufficient, diet becomes crucial. While few foods naturally contain high levels of vitamin D, many are fortified.

Naturally Vitamin D-Rich Foods

Foods that naturally contain vitamin D include fatty fish such as salmon, mackerel, and tuna, as well as cod liver oil, egg yolks, beef liver, and some mushrooms exposed to UV light.

Fortified Foods

Many common products are fortified with vitamin D, including milk, plant-based milks, cereals, orange juice, yogurt, and margarine. Checking nutrition labels is recommended to determine the vitamin D content.

Supplements: An Effective and Controlled Option

Supplements are a reliable way to ensure adequate intake, particularly for those with limited sun exposure or specific dietary needs. Vitamin D supplements are available as D2 (ergocalciferol) and D3 (cholecalciferol).

Choosing Between D2 and D3

Vitamin D3 is generally considered more effective at raising and maintaining blood levels than D2. Supplements typically contain D3, often derived from lanolin, though vegan alternatives from lichen are available. Consulting a healthcare provider is advised to determine the appropriate dosage.

Comparison of Vitamin D Sources


Source	Primary Form	Pros	Cons
Sunlight	D3	Most natural; free.	Risk of skin issues with overexposure; variable effectiveness based on location, season, skin tone, age, sunscreen.
Fatty Fish	D3	Natural food source; contains omega-3s.	Limited options; variable content; potential mercury in some species.
Fortified Foods	D2 or D3	Widely available; convenient.	Variable fortification; may have added sugar; not all products fortified.
Mushrooms (UV-treated)	D2	Good vegan/vegetarian source.	Limited availability; primarily D2.
Supplements	D2 or D3	Reliable, controlled dosage; easy to take.	Risk of toxicity with high doses; requires medical guidance for dosage; less natural than sun.

A Balanced Approach to Vitamin D Intake

Achieving healthy vitamin D levels often involves a combination of sensible sun exposure, a diet including natural and fortified sources, and potentially supplements. Consider your lifestyle and location to find the right balance. Regular blood tests and consultation with a healthcare professional can help monitor your vitamin D status. By utilizing a combination of sources, you can help ensure your body has the vitamin D needed for bone health and immune function.

Authoritative Link: For more in-depth information, explore the {Link: Harvard T.H. Chan School of Public Health nutritionsource.hsph.harvard.edu/vitamin-d/}.

Frequently Asked Questions

The best food sources include fatty fish like salmon, mackerel, and sardines, as well as cod liver oil, egg yolks, and fortified foods such as milk, cereals, and orange juice.

Most people can get enough vitamin D by spending approximately 5 to 30 minutes in the sun two to three times a week, with exposed arms, face, and legs. The exact time depends on factors like skin tone, location, and season.

In many regions far from the equator, the sun's UVB rays are not strong enough during the autumn and winter months for the body to synthesize adequate vitamin D. This is when dietary sources and supplements become especially important.

Both have benefits. Food sources provide vitamin D along with other nutrients, while supplements offer a controlled and reliable dosage. The best approach for many is a combination of diet, safe sun exposure, and potentially a supplement if deficiencies exist.

Vitamin D2 (ergocalciferol) comes from plant and fungal sources, while Vitamin D3 (cholecalciferol) comes from animal sources and sunlight exposure. D3 is generally considered more effective at raising and sustaining blood levels of vitamin D.

Groups at higher risk include older adults, people with darker skin, breastfed infants, those with limited sun exposure, and individuals with conditions that affect fat absorption or those with obesity.

It is not possible to get too much vitamin D from sun exposure, as the body self-regulates. However, taking excessively high doses of supplements can be harmful and lead to toxicity. Stick to recommended dosages unless advised otherwise by a doctor.