Vitamin D is found in fatty fish, egg yolks, fortified dairy products, certain mushrooms, and sunlight. Compared to most vitamins, relatively few foods contain it naturally, so most people get vitamin D from a combination of sun exposure, fortified foods, and supplements. Here’s a closer look at every major source and how much each one provides.
Fish and Seafood
Fatty fish are the richest natural food sources of vitamin D. Salmon, swordfish, tuna, and sardines all deliver meaningful amounts per serving. Cod liver oil is especially concentrated and has been used for generations as a vitamin D supplement in liquid form. A single serving of salmon or swordfish can supply most or all of your daily needs, which is 600 IU for adults under 70 and 800 IU for those older than 70.
Eggs, Liver, and Other Animal Sources
Egg yolks contain vitamin D, though the amount per egg is modest compared to fish. The vitamin D is entirely in the yolk, so egg white omelets won’t help here. Beef liver also provides some vitamin D, though it’s not as popular a dietary choice as it once was. If you eat eggs regularly, they contribute a small but steady amount to your overall intake.
Mushrooms: The Plant-Based Exception
Mushrooms are the only plant-based food that naturally produces vitamin D, and the amount varies wildly depending on how they’re grown. Standard store-bought portabella mushrooms contain roughly 10 to 11 IU per 100 grams, which is almost nothing. But when those same mushrooms are exposed to ultraviolet light for just 15 to 20 seconds during production, their vitamin D2 content jumps to around 446 IU per 100 grams.
Maitake mushrooms show even more dramatic variation. Depending on the producer, they can range from a negligible 4 IU per 100 grams up to 2,242 IU per 100 grams when grown under UV light. Look for packaging that says “UV-treated” or “high in vitamin D” if you’re relying on mushrooms as a source. Without that label, you’re likely getting very little.
Fortified Foods
Because so few foods contain vitamin D naturally, many everyday products are fortified with it. The most common include:
- Cow’s milk: Manufacturers can add up to 84 IU of vitamin D3 per 100 grams
- Plant-based milks (soy, almond, oat): Fortified with up to 84 IU of vitamin D2 per 100 grams
- Plant-based yogurt alternatives: Up to 89 IU of vitamin D2 per 100 grams
- Orange juice: Many brands are fortified with vitamin D
- Breakfast cereals: Commonly fortified, though amounts vary by brand
Fortification is voluntary, not mandatory, so you’ll need to check the nutrition label. A glass of fortified milk or orange juice at breakfast combined with a fortified cereal can add a meaningful amount to your daily total.
Sunlight
Your skin manufactures vitamin D when exposed to UVB rays from the sun. This is actually how most people get the majority of their vitamin D. When UVB light hits your skin, it converts a cholesterol compound in the outer layer of skin into a precursor of vitamin D3. That precursor then travels through the bloodstream and gets processed by the liver and kidneys into the active hormone your body uses.
About 10 to 15 minutes of sun exposure on bare skin, three or four times a week, is generally enough to maintain healthy vitamin D production. Several factors reduce this, though. Darker skin tones have more melanin, which slows vitamin D synthesis. Living at higher latitudes (farther from the equator) means weaker UVB rays, especially in winter. Cloud cover, air pollution, and sunscreen also block UVB. People who spend most of their time indoors or who cover most of their skin may produce very little vitamin D from sunlight alone.
One important detail: you cannot overdose on vitamin D from sun exposure. Your skin has a built-in regulation mechanism that breaks down excess precursors before they enter the bloodstream.
Vitamin D2 vs. D3
Not all vitamin D is identical. D2 (ergocalciferol) comes from plants and fungi, including UV-treated mushrooms and many fortified plant-based products. D3 (cholecalciferol) comes from animal sources and is the form your skin produces from sunlight. Both raise your blood levels of vitamin D, but D3 is substantially more effective. Research shows D3 can be up to ten times more potent than D2 because it raises blood levels higher and maintains them longer. D2 is cleared from the body more rapidly, and once you stop taking it, levels drop off faster than with D3.
If you’re choosing a supplement or comparing fortified products, D3 is the better option when available. Many plant-based milks use D2 due to its non-animal origin, which is worth knowing if you follow a vegan diet and rely heavily on these products.
How Much You Need
The recommended daily intake depends on your age:
- Infants (0 to 12 months): 400 IU
- Children and adults (1 to 70 years): 600 IU
- Adults over 70: 800 IU
These amounts are designed to maintain bone health and normal calcium metabolism. Vitamin D is fat-soluble, meaning your body absorbs it best when you eat it alongside some dietary fat. Taking a supplement with a meal that includes olive oil, nuts, avocado, or another fat source improves absorption compared to taking it on an empty stomach.
Getting Enough on a Plant-Based Diet
If you don’t eat fish, eggs, or dairy, your main vitamin D sources narrow to UV-treated mushrooms, fortified plant milks and cereals, sunlight, and supplements. Since plant-based fortified foods typically use D2 (the less potent form), you may need to be more intentional about combining multiple sources. A daily routine that includes fortified plant milk, UV-treated mushrooms a few times a week, regular sun exposure, and a D3 supplement (vegan D3 derived from lichen is available) covers your bases more reliably than any single source alone.