Nourish Your Body with Vitamin D3 and Vitamin K2: Food and Sunlight Sources

When it comes to maintaining strong bones and a healthy heart, two vitamins steal the spotlight: vitamin D₃ and vitamin K₂. These power-packed nutrients play a vital role in keeping calcium in our bones and out of our blood vessels as well as in keeping our immune systems robust. But how can you ensure you're getting enough of these essential vitamins? The answer lies in a combination of delicious foods, the great outdoors, and, for some, dietary supplements. Let’s explore the best sources of vitamin D₃ and K₂.

Sunlight: Your Free and Natural Source of Vitamin D

Vitamin D₃ promotes calcium absorption from the food we eat, supporting healthy bones. It also directs immune system function, reducing the risk of respiratory infections and autoimmune disease.^1,2 Adequate levels are vital to prevent bone disorders and to maintain overall health.

Vitamin D is produced from a type of cholesterol in the skin when exposed to UVB sunlight. It is one reason spending time outdoors can boost your mood and energy levels. Here’s how you can help your body produce the vitamin D₃ it needs to thrive:

Midday sun: Vitamin D is produced in response to UVB exposure to skin that does not have sunscreen. UVB rays are most prominent in the Northern Hemisphere between 10 AM and 2 PM during seasons of greatest daylight (April-October, October-April in the Southern Hemisphere). Therefore, it’s important to aim for about 10-30 of exposure during this time. However, it is also crucial to get the right amount of exposure for your skin tone. Those with darker skin may need longer periods of exposure to increase vitamin D levels than those with very light skin. D-Minder is a convenient app that can help you know how much UVB sunlight to get for your skin type.
Sun safety: Remember to balance sun exposure with skin protection. If you’re going to be out for periods longer than your skin pigmentation can handle without burning, make sure to use a nontoxic sunscreen to prevent sunburn. EWG.org is a wonderful resource for nontoxic sunscreen recommendations.

Food Sources of Vitamin D

During overcast days and winter months it can be tough to get enough vitamin D each day. Although there are only a handful of foods that contain vitamin D, they can be helpful when you need an extra boost. The following foods may be useful in boosting vitamin D levels when extra support is needed:³

Fatty fish: Salmon, mackerel, trout, sardines, and cod liver oil are excellent sources of vitamin D in addition to being high in anti-inflammatory omega-3 fatty acids.
Egg yolks: Eggs are an excellent source of protein, and the yolks are high in vitamin D as well as K₂, making them an effective food for addressing both nutritional needs.
Beef liver: Liver is a highly nutrient-dense food containing not only vitamin D but also a wide array of B vitamins, vitamin A, and minerals such as iron.
Fortified foods: Many dairy products as well as nondairy nut, seed, and oat milks are fortified with vitamin D₃.

Vitamin K₂: The Calcium Director

Vitamin K₂, a particular type of vitamin K, ensures that calcium is directed to the right places in our bodies, like the skeletal system. This is crucial for increasing bone density and maintaining healthy bones. Vitamin K₂ also prevents calcium from being deposited in the blood vessels where it can cause calcification and hardening of the arteries (a precursor to atherosclerosis and various forms of heart disease).

Vitamin K₂ in the form of menaquinone-7, MK-7, is more effective for supporting bone mineralization due to greater bioavailability and a longer half-life than other forms of vitamin K such as K₁ and MK-4.⁴

Vitamin K₂-rich foods include:

Natto: This traditional Japanese dish, made from fermented soybeans, is the richest source of vitamin K₂. Its strong flavor might be an acquired taste, but it’s worth acquiring!
Egg yolks from pastured chickens: Chickens that eat a natural diet and have exposure to sunlight produce higher levels of vitamin K₂ in their egg yolks,⁵ as evidenced by the orange yolk color (compared to the yellow of factory-farmed egg yolks) in eggs from chickens raised on a pasture.
Grass-fed butter, cheese, and beef: Similar to pastured chickens, cows that are exposed to sunlight and allowed to eat grass (i.e. pastured) produce higher levels of vitamin K₂ in their milk and fat. The fat of grass-fed cows also takes on a deeper-yellow color.
Additional fermented foods: Sauerkraut and other fermented vegetables provide some vitamin K₂. In addition to K₂ they are also a great source of beneficial probiotics supporting healthy digestion and a healthy gut.

Note the list above does not include leafy green veggies. Vitamin K₂ can only be found in the fermented and animal-sourced foods above. In addition, vitamin D and vitamin K are both fat-soluble vitamins, meaning that they require some fat for absorption, so unless the food itself is high in fat (i.e. fatty fish), be sure to eat these foods with healthy sources of fat (such as olive oil, olives, avocados, fatty fish, etc.).

Combining Forces: A Balanced Approach

To maximize the health benefits of vitamin D₃ and K₂, aim for a balanced approach that includes both food and sunlight. By combining delicious food choices and sensible sun exposure, you can ensure your body gets the vitamin D₃ and K₂ it needs. These vitamins work together to support your overall health, from strong bones to a healthy heart.

However, if you find that getting enough of each of these vitamins through food and sunlight alone is difficult, supplementation may be necessary. Always consult with your healthcare provider for medical advice regarding testing your vitamin D and K₂ levels as well as accurate dosage recommendations of each for you. Get more information on general dosage recommendations of vitamin D₃ and vitamin K₂.

So step outside, enjoy the sunshine, and savor the flavors of nutrient-rich foods. Your body will thank you for it!

If you enjoyed this blog, you may also like these:

Heart Health Heroes: The Vital Roles of Vitamin D3 and Vitamin K2
The Power Duo for Strong Bones: Vitamin D3 and Vitamin K2
Why You Should Include Vitamin K2 With Your Vitamin D3 Supplement
How Fat-Soluble Vitamins A, E, D, and K Work Together

References

1. Martineau AR et al. BMJ. 2017;356:i6583.
2. Aranow C. J Investig Med. 2011;59(6):881-886.
3. NIH. Vitamin D fact sheet for professionals. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/. Accessed July 10, 2024.
4. Halder M et al. Int J Mol Sci. 2019;20(4):896.
5. Rheaume-Bleue K. 2012. Vitamin K2 and the Calcium Paradox. Collins.