Getting enough vitamin D3 and K2 from food alone is genuinely difficult for most people, and understanding why helps explain why deficiency in both nutrients is so widespread globally. These two fat-soluble vitamins work closely together in the body, particularly around calcium metabolism and bone health, yet their natural dietary sources are quite different and, in many cases, quite limited. This article looks at the best foods high in vitamin D3 and K2, the realistic amounts you can expect from each, and who is most likely to need additional support beyond diet.
Why Food Sources Matter for Vitamin D3 and K2
Vitamin D3 (cholecalciferol) is unique among vitamins because the body can synthesise it through sun exposure on the skin. Vitamin K2 (menaquinone) is produced in small amounts by gut bacteria. However, neither of these internal sources is reliable for everyone, which is why dietary intake remains an important conversation. Before looking at specific foods, it is worth being honest: both nutrients have a fairly short list of meaningful dietary sources, and even the best food sources may not cover the full daily requirement for many individuals.
For a broader look at what these vitamins actually do in the body, see our guide on the science behind vitamin D3 and K2.
Natural Food Sources of Vitamin D3
Vitamin D3 specifically (as opposed to the plant-based D2 form) is found almost exclusively in animal-derived foods. This is an important distinction because D3 is generally considered more effective at raising blood levels of 25-hydroxyvitamin D than D2.
Fatty Fish
Fatty fish are consistently the richest dietary source of vitamin D3. Salmon, mackerel, sardines, herring, and trout all contain meaningful amounts, with wild-caught salmon generally providing more than farmed varieties. A standard serving of cooked salmon can deliver a substantial proportion of the recommended daily intake in a single meal, making it the standout food in this category. Canned fish, including sardines and tuna, also contributes, though usually at lower levels than fresh oily fish.
Cod Liver Oil
Cod liver oil is one of the most concentrated natural sources of vitamin D3 available from food. A single teaspoon provides more vitamin D3 than almost any other dietary source. It also contains vitamin A, which is worth noting because very high intakes of preformed vitamin A can interact with vitamin D metabolism. Cod liver oil is considered a supplement rather than a whole food by many definitions, but it is worth including here as it comes directly from a whole food origin.
Egg Yolks
Egg yolks contain vitamin D3, though in more modest amounts than fatty fish. The exact content varies considerably depending on how the hens are raised. Eggs from free-range or pasture-raised hens exposed to sunlight tend to have meaningfully higher vitamin D3 content than conventional eggs. This makes sourcing relevant if you are relying on eggs as a dietary contribution.
Beef Liver
Beef liver provides a small but real amount of vitamin D3 alongside a dense nutritional profile that includes vitamin K2 (discussed below), B vitamins, and iron. It is not a primary source of vitamin D3, but it contributes to overall intake in those who eat organ meats regularly.
UV-Exposed Mushrooms
Mushrooms exposed to ultraviolet light can synthesise vitamin D, though they predominantly produce D2 rather than D3. Some commercially available mushrooms are now UV-treated and labelled accordingly. While D2 has some biological activity, it is not the same compound as D3, so mushrooms are an imperfect substitute for those looking specifically for D3 from non-animal sources.
Natural Food Sources of Vitamin K2
Vitamin K2 is the less commonly discussed form of vitamin K. It differs from vitamin K1 (phylloquinone), which is found abundantly in leafy greens. K2 exists in several forms called menaquinones (MK-4 through MK-13), with MK-4 and MK-7 being the most studied. Food sources tend to fall into two camps: animal products containing MK-4, and fermented foods containing longer-chain menaquinones like MK-7.
Natto
Natto, a traditional Japanese food made from fermented soybeans, is by far the richest known dietary source of vitamin K2, specifically the MK-7 form. A small serving of natto contains exceptionally high levels of MK-7, far exceeding what is found in any other food. Its strong flavour and texture mean it is not widely consumed outside Japan, but for those who can incorporate it, it is genuinely in a category of its own. Population studies from Japan have linked regular natto consumption with better bone density outcomes, though this research has limitations.
Fermented Cheeses and Dairy
Hard and aged cheeses, particularly those produced through traditional fermentation, contain vitamin K2 in the MK-8 and MK-9 forms alongside smaller amounts of MK-4. Gouda, Brie, and Edam are frequently cited in research as reasonable dietary sources. The K2 content comes from bacterial fermentation during cheese production, meaning highly processed cheese products tend to have much less. Butter and full-fat dairy from grass-fed animals also contribute modest amounts of MK-4.
Meat and Organ Meats
Chicken, beef, and pork contain small amounts of vitamin K2 as MK-4, with organ meats tending to have higher concentrations than muscle meat. Chicken breast has notably lower content than chicken liver or chicken fat. Grass-fed and pasture-raised animals generally contain more K2 than grain-fed counterparts, reflecting the role of diet in nutrient composition.
Egg Yolks (Again)
Like vitamin D3, vitamin K2 (MK-4) is present in egg yolks, with pasture-raised eggs again showing higher content. The yolk contains both fat-soluble vitamins, making it a convenient dual source, albeit in quantities that are relatively modest compared to the foods listed above.
Top Food Sources at a Glance
| Food | Primary Nutrient | Form | Relative Amount | Notes |
|---|---|---|---|---|
| Wild salmon (cooked) | Vitamin D3 | D3 | Very high | Wild-caught higher than farmed |
| Cod liver oil | Vitamin D3 | D3 | Very high | Also contains vitamin A; use cautiously |
| Sardines (canned) | Vitamin D3 | D3 | Moderate-high | Good budget option |
| Egg yolks (pasture-raised) | Vitamin D3 and K2 | D3, MK-4 | Moderate | Dual source; quality matters |
| Natto | Vitamin K2 | MK-7 | Exceptionally high | Richest known K2 food source |
| Aged hard cheese (e.g. Gouda) | Vitamin K2 | MK-8, MK-9 | Moderate | Traditional fermented varieties preferred |
| Chicken liver | Vitamin K2 | MK-4 | Moderate | Also provides D3 in small amounts |
| UV-exposed mushrooms | Vitamin D | D2 (not D3) | Variable | D2 only; less effective than D3 |
Dietary Factors That Affect Absorption
Both vitamin D3 and K2 are fat-soluble, which means they are absorbed more effectively when consumed alongside dietary fat. Eating fatty fish with a meal that contains fat is generally redundant since the fish itself supplies fat, but taking supplements or eating lower-fat sources of these vitamins alongside healthy fats like olive oil, avocado, or nuts can improve absorption. Conditions that impair fat absorption, such as inflammatory bowel disease, Crohn’s disease, coeliac disease, and certain liver conditions, can significantly reduce how much of either vitamin actually reaches circulation from food. Magnesium is also involved in vitamin D metabolism, and low magnesium status may blunt the effectiveness of vitamin D from any source.
Who Struggles to Get Enough From Diet Alone
Several groups are at particular risk of inadequate vitamin D3 and K2 from food sources alone:
- People following vegan or strict vegetarian diets have very limited access to D3 specifically, and almost no access to preformed K2 outside of natto and some fermented plant foods.
- Older adults have reduced skin synthesis of vitamin D and often eat smaller, less varied diets.
- People with fat malabsorption conditions absorb less of both fat-soluble vitamins regardless of intake.
- Those living at high latitudes or spending little time outdoors cannot rely on sun exposure to compensate for low dietary D3.
- People who rarely eat fermented foods or oily fish, which describes a large proportion of many Western populations.
- Individuals on certain medications, including some anticoagulants and cholesterol-lowering drugs, may have altered vitamin K metabolism.
The NIH Office of Dietary Supplements provides detailed reference values and population data on vitamin D adequacy that are worth reviewing.
Dietary Sources vs. Supplements
The honest answer is that for most people, food sources of vitamin D3 and K2 are valuable but are unlikely to be sufficient on their own, particularly for vitamin D3 in northern climates or for K2 in populations that do not regularly eat natto or traditional fermented cheeses. Supplements allow for consistent, measurable dosing in a way that food cannot easily replicate given the variability in nutrient content between food sources, cooking methods, and individual absorption. That said, whole food sources come with co-occurring nutrients, such as omega-3 fatty acids in oily fish and other fat-soluble vitamins in organ meats, that may support overall health in ways a single-nutrient supplement does not.
For those considering supplements, combining D3 and K2 in a single product has become increasingly common based on their complementary roles in calcium regulation. You can read more about how D3 and K2 work together and about choosing the right supplement format in our related guides.
The practical approach for most people is to prioritise food sources as a foundation while acknowledging the limits of diet, particularly during winter months or in the absence of regular sun exposure, and to consider supplementation as a consistent, reliable top-up rather than a replacement for a varied diet.
Frequently Asked Questions
Can I get enough vitamin D3 from food without any sun exposure?
For most people, this is very difficult. Even with regular consumption of oily fish and eggs, dietary intake of vitamin D3 alone is unlikely to maintain optimal blood levels, particularly in autumn and winter at latitudes above approximately 35 degrees north or south. Sun exposure on the skin remains the most efficient way to raise vitamin D status, which is why deficiency is so common in northern countries and among people who spend most of their time indoors regardless of diet.
Is the K2 in cheese the same as the K2 in supplements?
Not exactly. Cheese primarily contains longer-chain menaquinones (MK-8 and MK-9), while most supplements use either MK-4 or MK-7. MK-7, derived from natto fermentation, has a longer half-life in the body than MK-4 and is the form most commonly used in combined D3 and K2 supplements. All forms have biological activity, but MK-7 at relatively low doses appears to have a more sustained effect on K2-dependent proteins in the body compared to shorter-chain forms.
Do I need to eat natto to get meaningful amounts of K2?
Not necessarily, but natto is genuinely unrivalled as a food source of MK-7 K2. If natto is not a realistic part of your diet, moderate amounts of aged hard cheese, pastured dairy, eggs, and organ meats can collectively contribute to K2 intake, though in much smaller amounts. People who do not regularly eat these foods and who do not eat natto are likely to have quite low dietary K2 intake, which is one reason K2 supplementation is often recommended alongside D3.
Are there any plant foods that provide vitamin D3?
No plant foods naturally contain vitamin D3. Plants produce vitamin D2 when exposed to ultraviolet light, not D3. UV-exposed mushrooms are often cited as a plant-based vitamin D source, and while they do raise vitamin D levels in the body, the form is D2 (ergocalciferol), which is metabolised somewhat differently. For vegans seeking D3 specifically, there are now vegan D3 supplements derived from lichen, which is a technically non-animal source of cholecalciferol.
Can cooking destroy vitamin D3 or K2 in food?
Both vitamins are relatively heat-stable compared to water-soluble vitamins, so normal cooking methods do not dramatically reduce their content. Some loss does occur with very high temperatures or prolonged cooking, and because both are fat-soluble, they can leach into cooking oils or liquid if food is cooked in a way that drains fat away. Grilling fish rather than poaching it in water, for example, preserves more of the fat-soluble nutrients in the fish itself. Overall, cooking is not a major concern for these two vitamins compared to preparation method and food quality.
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Content is for informational purposes only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.
