Fatty Fish: An Example of a Source of Vitamin D

November 19, 2025 •

4 min read

According to the National Institutes of Health, few foods naturally contain vitamin D, which is essential for bone health and immune function. Among the best natural dietary options, fatty fish serves as a prime example of a source of vitamin D, providing significant amounts of this crucial nutrient. Understanding which foods are naturally rich in this vitamin can be a powerful tool for managing your nutritional intake effectively.

Quick Summary

Fatty fish, including salmon, tuna, and sardines, are one of the most potent natural sources of vitamin D. Fortified foods, like milk and cereals, and sun-exposed mushrooms also provide the vitamin. Supplements are another option for those with limited access to food sources or sunlight.

Key Points

Fatty Fish: Oily fish like salmon and tuna are a top natural source of vitamin D, specifically the highly absorbable D3 form.
Fortified Foods: Many dairy products, plant-based milks, cereals, and juices are fortified with vitamin D to increase public intake.
Sunlight Exposure: The body produces vitamin D naturally when skin is exposed to UVB rays, though this is dependent on location and time of year.
Mushrooms: Certain mushrooms exposed to UV light can provide vitamin D2, making them one of the few natural non-animal sources.
Supplements: For those with dietary restrictions or insufficient sun exposure, supplements containing vitamin D2 or D3 are a reliable option.
Egg Yolks: Eggs from free-range chickens, which get more sun, naturally contain more vitamin D in their yolks.
Cod Liver Oil: This supplement is an extremely concentrated source of vitamin D, providing a significant boost.

Why is fatty fish a great example of a source of vitamin D?

Vitamin D is a fat-soluble vitamin that plays a critical role in calcium absorption, bone mineralization, and immune system regulation. The body primarily produces it through direct exposure of skin to sunlight. However, dietary intake is essential, especially for those with limited sun exposure due to geographic location, season, or lifestyle. This is where fatty fish shines as an exemplary dietary source.

The power of fatty fish

Fatty fish, often called oily fish, contains a high concentration of vitamin D3, the same type produced in the human body. The amount can vary depending on whether the fish is wild-caught or farmed, but both offer substantial benefits. For instance, a 3.5-ounce serving of sockeye salmon can provide a large portion of the daily recommended intake.

Other notable examples of fatty fish and their vitamin D content include:

Salmon: A popular and potent source, whether wild or farmed.
Sardines: These small, oily fish are packed with nutrients, including vitamin D.
Cod Liver Oil: A highly concentrated supplement derived from cod liver, offering a significant dose of the vitamin.
Tuna: Canned light tuna also contains a good amount of vitamin D.
Mackerel: Another excellent oily fish choice with high vitamin D levels.

Other dietary and non-dietary sources of vitamin D

While fatty fish is a top contender, several other sources can help you meet your daily vitamin D requirements. These include fortified foods, certain mushrooms, and the ever-important sunlight.

Fortified foods

Many common food products are fortified with vitamin D to help boost public intake, making them accessible sources for many people. Examples include:

Milk: Both dairy and plant-based milks (soy, almond, oat) are often fortified.
Cereals: Many ready-to-eat breakfast cereals have vitamin D added.
Orange Juice: Some brands of orange juice are fortified with vitamin D.
Yogurt and Cheese: Certain types of yogurt and cheese may also be fortified.

Mushrooms and sunlight

Mushrooms are one of the few non-animal food sources of vitamin D, specifically D2. When exposed to ultraviolet (UV) light, either naturally in the wild or intentionally by commercial growers, mushrooms can produce substantial amounts of the vitamin. In fact, some UV-exposed mushroom varieties can contain high levels of vitamin D.

Of course, the most direct non-dietary source is sunlight. The body's natural production of vitamin D from UVB exposure is a highly efficient process. However, factors like time of year, geographical location, and skin pigmentation can affect production. It's also crucial to balance sun exposure to minimize skin cancer risk.

Natural vs. fortified sources: A comparison

To help clarify the differences between natural and fortified sources, here is a comparison table:


Feature	Natural Food Sources (e.g., fatty fish, eggs)	Fortified Food Sources (e.g., milk, cereal)
Form of Vitamin D	Primarily vitamin D3 in animal products; D2 in mushrooms.	Can contain either D2 or D3, depending on the fortification process.
Potency	Often very high, especially in sources like salmon and cod liver oil.	Varies widely by brand and product; content is typically listed on the nutrition label.
Bioavailability	Generally considered highly bioavailable, especially D3.	Good bioavailability, though some studies suggest D3 may be slightly more effective at raising serum levels long-term compared to D2.
Source Origin	Naturally occurring in the food source.	Added by manufacturers to increase the food's nutritional value.
Suitability	Excellent for those who eat animal products; specific mushrooms for vegetarians.	Ideal for those who may not get sufficient vitamin D from other dietary sources; can be suitable for vegans.

Conclusion: Incorporating vitamin D sources into your diet

Knowing what is an example of a source of vitamin D is the first step towards ensuring you maintain adequate levels. While fatty fish offers one of the most potent natural dietary options, a combination of sources is often the best strategy. Incorporating fortified foods and, when safe and appropriate, moderate sun exposure can help you build a well-rounded approach to vitamin D intake. For those with concerns about their levels, a healthcare provider can recommend supplements to ensure you meet your needs. A balanced and varied diet, rich in options like salmon, fortified milk, and UV-treated mushrooms, provides a robust foundation for a healthy lifestyle. For more information, consider reading resources from authoritative health bodies like the National Institutes of Health.

Practical list of sources

To simplify your meal planning, consider adding these items to your diet regularly to boost your vitamin D intake:

Wild salmon and mackerel
Canned tuna or sardines
Cod liver oil
Beef liver
Free-range egg yolks
UV-exposed mushrooms (maitake, portobello)
Fortified milk (dairy or plant-based)
Fortified cereals and orange juice
Supplements (if dietary intake is insufficient and advised by a professional)

Frequently Asked Questions

Fatty fish, such as salmon, mackerel, and tuna, are widely regarded as one of the best natural food sources of vitamin D.

Yes, many foods fortified with vitamin D, including milk, cereals, and orange juice, are a reliable and accessible way to boost your daily intake.

Mushrooms that have been exposed to ultraviolet (UV) light can produce significant amounts of vitamin D2, making them a good option, especially for vegetarians and vegans.

Sunlight is a primary way the body produces vitamin D naturally. However, sun exposure should be balanced with caution to minimize skin cancer risks.

Vitamin D supplements, available as D2 or D3, provide a concentrated dose of the vitamin, offering a reliable alternative for those with limited sun exposure or dietary intake.

While all egg yolks contain some vitamin D, the amount can be higher in eggs from free-range chickens that have more exposure to sunlight.

The body can use both, but some evidence suggests that vitamin D3 (found in animal products and produced by the skin) may raise serum levels more effectively and for longer than D2 (found in plants and fungi).