If you live anywhere north of a line running roughly through San Francisco, Richmond, and St. Louis — which covers most of the country — the winter sun sits too low in the sky to do one of its quietest but most important jobs. From about November through March, your skin makes almost no vitamin D, no matter how many midday walks you take. (Boston, at 42°N, is the textbook case: classic research found that skin there produces essentially zero vitamin D for roughly four months a year.) National survey data consistently shows that a large share of U.S. adults fall short on vitamin D, and the gap widens in winter and across the northern half of the country. So “how do I get vitamin D from food?” isn’t a theoretical question — it’s a practical one for most of the year.
Here’s the catch: vitamin D is genuinely hard to eat in meaningful amounts. It shows up in only a narrow set of foods, most of them fatty. This guide won’t replace a blood test (the lab marker is called 25(OH)D), and it won’t recommend a specific supplement. What it will do is show you which foods actually deliver vitamin D, how much each one contains, and what helps — or quietly sabotages — absorption.
Below: a full table with real numbers per 100 g (3.5 oz), the top 10 sources explained, the absorption factors that matter, and answers to the questions people ask most.
Table of Contents
Natural Food Sources of Vitamin D
Vitamin D comes in two forms: D3, the “animal” form (from fish, eggs, liver), and D2, the “plant” form (from mushrooms and fortified plant foods). The chemical names — cholecalciferol and ergocalciferol — you can safely ignore. For choosing food, the only thing that matters is the number after the letter D.
Research shows something straightforward: at the same dose, D3 raises blood vitamin D more effectively than D2. In other words, the animal form does more per unit.
Vitamin D content by food (per 100 g / 3.5 oz)
| Food | Amount (IU) | % of RDA (600 IU) | Form | Notes |
|---|---|---|---|---|
| Cod liver oil | ~10,000 IU per tbsp | >1,500% | D3 | The most concentrated source there is — use by the spoonful, not the serving |
| Wild salmon (cooked) | 526–988 IU | 88–165% | D3 | Wild has 2–4× more D3 than farmed |
| Farmed salmon | 200–360 IU | 33–60% | D3 | Depends on what the fish was fed |
| Rainbow trout (farmed) | 645 IU | 108% | D3 | One of the richest sources among affordable fish |
| Herring (Atlantic) | 216 IU | 36% | D3 | Inexpensive where you can find it |
| Mackerel | 360 IU | 60% | D3 | Fatty fish; holds its D3 well when cured |
| Sardines, canned in oil | 193 IU | 32% | D3 | A convenient, budget-friendly staple |
| Tuna, canned in oil | 269 IU | 45% | D3 | Check the label — packed in water has less |
| UV-treated mushrooms (white, portobello) | 400–1,000 IU | 67–167% | D2 | Regular mushrooms have only 5–20 IU |
| Egg yolk | 37 IU per yolk | 6% (1 yolk) | D3 | Pasture-raised hens’ eggs have 2–3× more |
| Beef liver | 49 IU per 100 g | 8% | D3 | Modest for D, but rich in B12 and iron |
| Hard cheese | 7–24 IU per oz | 1–4% | D3 | A trace source, but small amounts add up |
| Fortified milk | 115–130 IU per cup | 19–22% | D3 (added) | In the U.S., fortification is standard |
| Fortified plant milk | 100–144 IU per cup | 17–24% | D2/D3 | Soy, oat, almond — only if the carton says so |
| Fortified breakfast cereal | 40–140 IU per serving | 7–23% | D2/D3 | Check the panel — many brands don’t fortify |
Source: USDA FoodData Central (fdc.nal.usda.gov), updated 2024–2025.
What this means in practice. Fatty fish is in a league of its own. A single serving of wild salmon (about 5 oz) roughly covers a full day’s requirement. Almost everything else delivers 5–25% per serving, so covering your needs from food alone takes either regular fish or a deliberate combination of several foods. Because D3 from animal sources absorbs better than D2 from mushrooms, betting on fatty fish is the most efficient strategy for a mixed diet.
Top 10 Foods Highest in Vitamin D
1. Cod liver oil
The undisputed champion: one tablespoon beats a week’s worth of the RDA. Alongside D3, it carries vitamin A and omega-3s. Don’t exceed a tablespoon a day, though — with the D you also get a large dose of vitamin A (the active form is retinol), and too much of it can stress the liver.
2. Wild salmon
Up to 988 IU per 100 g of baked fillet. Wild is far richer than farmed: in the ocean, salmon eat plankton and small fish loaded with vitamin D, while farmed salmon get formulated feed.
3. Rainbow trout
A surprise standout among affordable fish: farmed trout delivers about 645 IU per 100 g. Fatty, tender, and easy to cook — a solid alternative to pricey salmon.
4. UV-treated mushrooms
Plain mushrooms contain almost no vitamin D. But mushrooms hold a compound called ergosterol that converts to vitamin D2 under ultraviolet light — the same way our skin makes D under the sun. Some brands print “UV-treated” on the package, and it genuinely works. You can even “charge” mushrooms at home: set them gill-side up in direct sun for 15–30 minutes.
5. Mackerel
360 IU per 100 g, plus a high dose of omega-3s. Smoked or cured mackerel keeps most of its D3, since the vitamin stands up to moderate heat and salt.
6. Canned tuna
Up to 270 IU per 100 g packed in oil; less in water. Convenient for everyday meals — but watch mercury in large species like bigeye and bluefin. The FDA advises limiting these; two servings a week is a reasonable ceiling.
7. Sardines
193 IU per 100 g, with a bonus: calcium from the soft bones. A budget source that gets overlooked far too often.
8. Herring
216 IU per 100 g of Atlantic herring. Less of a staple on American shelves than canned salmon or sardines, but worth grabbing when you see it — and pickled or cured versions lose under 10% of their vitamin D.
9. Fortified milk and plant milks
A genuine win in the U.S., where vitamin D fortification of milk has been standard since the 1930s. Don’t assume, though: many plant milks are fortified to similar levels, but only if the carton actually says so — check the label.
10. Egg yolks
37 IU per yolk — a small number, but a regular one. Eggs from pasture-raised hens have 2–4× more, because the hens synthesize D3 in the sun themselves.
Absorption and Interactions: What Helps and What Hurts
What IMPROVES vitamin D absorption
Fat in the same meal. Vitamin D dissolves only in fat. With no fat on the plate, your body never switches on the mechanism that pulls the vitamin across the gut wall. One study found a striking effect: taking vitamin D with the largest meal of the day raised blood levels about 50% higher than taking it on an empty stomach. In practice, a salad with salmon and olive oil delivers more than the same fish poached and eaten plain.
Magnesium. The vitamin D you eat isn’t yet the “working” form. Before your body can use it, the liver and kidneys have to activate it — and that takes magnesium. Without enough magnesium, even plenty of dietary vitamin D leaves little usable in the blood.
Vitamin K2. Think of K2 as a traffic cop: it directs calcium into your bones and keeps it from settling on artery walls. The best natural pairing is fatty fish (your D3) with fermented foods or aged cheese (your K2). Together they work better than either alone.
What INTERFERES with absorption
Long cooking at high heat. Deep-fry your fish and it loses 25–40% of its vitamin D — nearly half. Baking, grilling, and steaming preserve far more.
GI conditions. Some chronic gut conditions — celiac disease (gluten intolerance), Crohn’s disease (intestinal inflammation), and cystic fibrosis (an inherited disorder) — impair fat absorption, and vitamin D goes down with it. If you have one of these diagnoses, hitting your target from food alone is nearly impossible.
Certain medications. Drugs that can blunt vitamin D absorption include weight-loss medications (such as orlistat), cholesterol-lowering bile-acid binders (like cholestyramine), and some anti-seizure drugs. If you take any of these, talk it through with your doctor — don’t change your regimen on your own.
A very low-fat diet. Ultra-low-fat eating sets a trap: you eat the “healthy” fish, but without fat on the plate your body can’t properly absorb the vitamin D from it. The paradox is that healthy becomes less healthy.
Common Myths About Vitamin D in Food
“Milk is the main source of vitamin D”
This idea traces back to a 1930s American public-health campaign, when the U.S. began fortifying milk to fight rickets. The campaign worked — and fortified milk really does supply about 120 IU per cup. But that’s exactly the point: milk is a helpful contributor, not a one-stop solution. You’d need several glasses a day to approach your target, and plenty of people drink little milk or switch to plant milks that may not be fortified at all. The real workhorses are fatty fish and clearly labeled fortified foods.
“A tan replaces food sources completely”
Skin can make vitamin D under the sun — but only when the sun is high enough in the sky. Here’s a simple test: if your shadow is shorter than you are, the sun is “working” and your skin is making vitamin D. If your shadow is longer, it isn’t. In a city like Boston or Chicago, that “working” sun only shows up roughly April through September, between about 10 a.m. and 3 p.m. From October through March, skin synthesis drops to essentially zero, even on a bright, clear day. For much of the country, that makes food and/or supplements the main source for half the year.
“Mushrooms are a complete fish substitute for vegans”
Mushrooms — especially UV-treated ones — are a real source of vitamin D, but in the D2 form. And D2 absorbs about 1.5–2× less efficiently than the animal-derived D3 in fish. Vegans usually struggle to hit their target from food alone; the common workaround is a D3 supplement derived from lichen (the only plant-based source of D3) — but that’s a decision to make with your doctor, based on a 25(OH)D blood test.
The Bottom Line
Meeting your vitamin D needs from food is hard, but not hopeless. Fatty fish two or three times a week, plus regular eggs, cheese, UV mushrooms, and fortified foods, gives most adults a real foundation in the warmer months. From November through March, when skin synthesis shuts down, food usually isn’t enough on its own — and that’s when a decision about supplementing is best made with your doctor, based on a 25(OH)D blood test, not “just in case.”
The most practical move you can make today: plan two fish into next week’s menu (one fatty, one convenient canned option for the office), add eggs at breakfast three or four times a week, and keep a stash of salmon or mackerel in the freezer for a fast dinner. That alone covers 60–80% of your needs with almost no effort.