Digging for Vitamin D

What are the best food sources of the “sunshine” vitamin (if you don’t get any sunshine)?

It’s January in Seattle, and most people I know are planning (or dreaming of) a vacation to a sunnier spot like Arizona, Mexico, southern California, or Hawaii. And that isn’t too surprising, considering that we don’t get much sun this time of year – and as a result, over half of the people living in the Northwest have clinically low levels of Vitamin D.

It’s not just Seattle’s reputation for drearily gray and rainy weather that prevents Vitamin D synthesis in the Winter months, it’s also our northern latitude. As the map below indicates, over half of the US is unable to produce Vitamin D during the winter months, so it’s wise to pay attention to this essential nutrient this time of year.

Vitamin-D-Map Harvard

Image Source: “Time for more Vitamin D” Harvard Nutrition Source

Vitamin D is essential for numerous body systems (immune, skeletal, cardiovascular), but unfortunately not found in many foods. Many North-Westerners rely on a supplement to meet their needs during the Winter months, and that is definitely the easiest way to go. But, if you want to try and meet your requirement for the “Sunshine Vitamin” exclusively through foods when there is no sunshine – this post is for you!! Food sources of Vitamin D are quite limited, so you really do have to go digging for them…


Seafood contains more vitamin D than any other food group by a landslide. Wild Alaskan salmon is an exceptional source, providing over half of your Daily Value per 4oz serving. Wild salmon provides about five times the amount of Vitamin D as farmed (Atlantic) salmon, making it the best choice for both nutrition and the environment.

Canned tuna or sardines are also decent sources, providing about 25% of your Daily Value per 3oz serving – versatile and a great choice for your pocketbook too! Halibut is another NW favorite that is especially rich in Vitamin D; and shrimp, cod, oysters and herring are also popular options… pretty much all seafood provides a good dose of vitamin D. If you are vegan, or don’t like to eat seafood – you should definitely consider a Vitamin D supplement.


Eggs contain a reliable dose of Vitamin D for regular breakfast eaters, but keep in mind that all of the Vitamin D is found in the yolks (none in the egg whites), so I always advise eating the whole egg to get the whole nutritional package. One egg yolk provides approximately 6-8% of your Daily Value for Vitamin D (depending on the size of the egg). So if you regularly eat a 2-egg breakfast (like me), that can be up to 15% of your daily value…not too shabby!

Pasture-raised hens spend more time outdoors than any other egg production practice, and this outdoor sun exposure significantly boosts the vitamin D content of their eggs, making pasture-raised eggs the best choice for both nutrition and animal welfare. A report in Mother Earth News found that Pasture Raised Eggs had 6 times the amount of Vitamin D as conventional (factory farm) eggs, and this was confirmed in a 2013 USDA report.

I haven’t seen research to confirm this, but I speculate that pasture raised eggs from Texas will have more vitamin D than NW produced eggs, so the idiom that everything’s bigger in Texas might apply to Vitamin D levels as well – as a 2-egg “Texas” breakfast might boost vitamin D levels up over 50% of your DV, if you can dig up some TX eggs, such as Vital Farms, a pastured egg producer increasingly available here in the NW.


Mushrooms are quite unique in their ability to produce vitamin D from UV light exposure (sunlight) just like humans, but unfortunately today’s supermarket mushrooms contain only modest amounts of vitamin D, because commercial mushrooms are grown indoors.  We can actually boost the amount of Vitamin D, by exposing mushrooms to sunlight, or UV-light (indoors), and some companies are now marketing Vitamin D fortified mushrooms that have been treated with UV-light after being harvested to boost Vitamin D levels up to 100%.

You can actually boost the vitamin D in your mushrooms yourself by exposing them to UV light (but this only works in the summer months, just like in people): simply place your shrooms on a baking sheet and place them in the sunlight for an hour before cooking (think mushroom tanning salon!). If you slice the mushrooms first, this will increase their surface area, and each slice will therefore get more UV exposure, and will translate into more vitamin D in your food.

A case study in the UK found that if you don’t have access to sunshine, you can also use an indoor UV light to boost the Vitamin D content of your mushrooms. A vegan who didn’t want to take a vitamin D supplement, instead bought a UV light, and was able to raise his blood levels of Vitamin D within just 3 months, by eating mushrooms each day that were “home-fortified” with Vitamin D.

You can also learn to forage for wild mushrooms, as there are numerous groups that lead foraging meet ups and educational sessions as a unique way to connect with nature and learn about fungi. I will never forget the “hen of the woods” I dug up and store in the freezer, so that I had wild mushrooms throughout the year. Grifola frondosa (aka Maitake) is a notable medicinal mushroom often found at the base of oak trees, and is featured in the photo below. It is also known as the “dancing mushroom” and I can attest to the dance you will do when you find one of these beauties growing in the woods! Wild mushrooms provide approximately 12% of your Daily Value per serving.


Dairy products

Most people incorrectly list milk as the top source of Vitamin D, because seafood wins by a landslide. If you read the milk carton closely you will see that milk is fortified with Vitamins A and D. A glass of unfortified, whole milk provides a modest 5% of your daily value, so the 30% Daily Value you see on the carton is a result of fortification.

When milk is “skimmed” of its fat to produce lower fat milks, the vitamin D is also removed, because Vitamin D is a fat-soluble nutrient. Luckily, low-fat (and skim) milks are required to be fortified with vitamin D, to ensure that we don’t lose this precious nutrient in lower-fat milks. However, the loss of fat during skimming inhibits absorption of Vitamin D drastically. Cheeses and other dairy products like ice cream and yogurt are not required by law to be fortified with vitamin D, so they would only provide traces of vitamin D if derived from whole milk.


Animal products contain trace amounts of Vitamin D, dependent on species and outdoor access. According to the USDA database, pork has a little more than beef, and turkey is higher than chicken. Liver tops any other cut of meat, so that is an economical option to maximize your meat budget. I suspect that free-range, pastured, and grass-fed meats would offer superior quantities of the “sunshine vitamin” than their conventional counterparts – but surprisingly nobody has researched this intriguing theory.

Fortified Foods & Supplements

Every day there are more and more foods getting fortified with the sunshine vitamin, including orange juice, milk alternatives (soy, almond, hemp, etc), nutrition bars, breakfast cereals, and fortified beverages creating a range of reliable sources of Vitamin D for many people. (I’m a little concerned about the increasing fortification of foods with vitamin D, so maybe I will get into that in a future post, especially now that Vitamin D will be getting more prominence on the new Nutrition Facts Panels)

The most convenient way to ensure that you (and your family) are meeting your daily vitamin D requirement during the winter months is to consider a supplement. Tablets, softgels, and multi-vitamins are available, but the most economical way to supplement with vitamin D is with a liquid supplement. Just place a drop or 2 of this tasteless, odorless, colorless liquid into your scrambled eggs, on top of your pizza, or in a smoothie, and no one will even know they are getting a boost of the sunshine vitamin!

The majority of vitamin D supplements are derived from lanolin (wool oil) and a few are derived from fish or cod liver oil. An increasing trend is plant derived vitamin D supplements, either derived from mushrooms (labeled as ergocalciferol) or algae. Generally, plant-sources come in the form of D2, while animal sources are in the form of D3, but manufacturers are now able to produce D3 from plant sources such as lichens. D3 is generally considered to be a more bio-available form, but researchers have found that high doses of D2 can produce very similar results as D3. Supplements labeled “vegetarian” are usually derived from lanolin, but vegans should look for D2, or products specifically labeled vegan.

 How much do you need?

According to the IOM, adults require 600 IUs/per day. This Daily Value was increased from 400 IUs a few years ago, but many people (and even supplements) still inaccurately list 400 IUs as the daily requirement on labels and websites. The Vitamin D content of foods and supplements are measured in International Units (IUs), and 1 mg of vitamin D = 40 IUs. Infants need at least 400 IUs of vitamin D each day (up to 1000 IUs is considered safe for infants).

Health professionals often recommend higher intakes for adults (1000-2000 IUs) to boost vitamin D levels especially during winter, and many believe that the IOM’s 600 IUs/day is still too low, as blood levels peak with intakes between 1000-2000 IUs.

I always advocate getting nutrients from whole food sources, rather than relying on supplements because whole foods provide additional benefits not found in supplements. But honestly, most of us in the NW need to take a vitamin D supplement during the winter months (October through March), especially to reach 2000 IUs/day. As the table below highlights, if you do not eat seafood on a regular basis, it can be very difficult to meet this requirement from foods alone.

Food Serving size Vitamin D, in IUs

& (%) of Daily Value

Wild Alaskan Salmon 3 oz 500 (80%)
Sardines (canned) 3 oz 230 (40%)
Halibut 3 oz 200 (33%)
Milk (fortified w/Vit D) 1 cup 100 (17%)
Fortified Soy milk / Orange juice 1 cup 100 (17%)
Pork shoulder 3 oz 80 (13%)
Ground Turkey 3 oz 48 (8%)
Egg* 1 egg 40 (7%)
Mushrooms ½ cup 20 (3%)

*Pasture-raised chickens spend more time outdoors than any other eggs on the market, and this outdoor sun exposure boosts the vitamin D content of their eggs, this table shows the vitamin D content of conventional eggs…pastured eggs can be up to 6 times higher.

Why do we need vitamin D?

“the two basic items to sustain life are sunshine and coconut milk”

This quote comes from Ricco “Ratso” Rizzo (aka Dustin Hoffman) in 1969’s Best Picture Midnight Cowboy –waxing poetic about the many joys of living in warmer climates such as Florida, where Ratso claimed that coconuts were so common they were sold at gas stations in Florida. It’s too bad that Ratso never made it to the “sunshine state” to benefit from his own dietary/lifestyle prescription, because the importance of the sunshine vitamin becomes more and more evident each year.

15 years ago, when I earned my first degree in Nutrition, the nutrition community only recognized Vitamin D’s role in calcium regulation and bone metabolism; but now we now that “Vitamin” D actually functions more like a hormone in our bodies, regulating numerous body systems. In addition to regulating calcium in our blood, Vitamin D also regulates our immune system, blood pressure, and our secretion of insulin – a hormone that tightly controls our blood sugar levels. A Vitamin D deficiency seems to increase the risk for osteoporosis, auto-immune diseases (including MS and type 1 diabetes), muscle weakness/pain, and even colds and flus. Every single cell in the human body has a receptor for Vitamin D, suggesting the widespread significance of this sunshine vitamin in “sustaining life” as Ratso proclaimed so clearly back in 1969.

It’s fascinating to consider the challenge of meeting our Vitamin D requirement here in the Northwest. Sure, we can complain because of the long Vitamin-D-winter that makes it impossible to synthesize vitamin D from October to March…but it seems like a strange coincidence that our environment supports a wide range of Vitamin D rich foods like salmon and mushrooms that can be dried and preserved so that we have a reliable way to find vitamin D even when the sunshine isn’t around.

There’s nothing wrong with relying on a supplement to meet your Vitamin D requirement in the Winter, but if you want to get all your nutrients from wholesome foods, then here’s my recipe for a NW-inspired frittata with all of the Vitamin D superfoods: salmon, eggs, dairy.  An easy recipe to give your cells a little “taste of sunshine” any time of the year.


A Very-Vitamin-D-licious Fritatta!

The most reliable food sources of vitamin D are wild salmon, mushrooms, dairy products, and eggs – so this recipe combines them all together into a very simple frittata, cooked in a mixture of olive oil and butter to provide adequate fat to maximize vitamin D absorption. This frittata can be enjoyed warm or cold, and pairs nicely with wither a green salad or some roasted root vegetables.


  • About 6 eggs (don’t you dare toss out those egg yolks!)
  • ¼ cup Milk (use whole milk for the most natural vitamin d)
  • ½ cup smoked salmon, flaked into tiny pieces
  • Extra Virgin Olive Oil/butter for cooking (I like to use a 50/50 mix)
  • 2 cups mushrooms, sliced or diced
  • 2 shallots, chopped
  • 4 cloves garlic, minced
  • 1 tsp dried herbs – thyme, oregano, etc…
  • Salt and pepper to taste
  • About ¼ cup to ½ cup of Grated cheese (parmesan or gouda are personal faves)


First, cook the mushrooms and shallots in oil/butter mixture for about 5 minutes. Then stir in the garlic and herbs, and cook for another 5 minutes (or so).

While the mushrooms are cooking, whisk the eggs and milk together, and add a few dashes of salt, pepper, and dried herbs (if desired).

Let the mushroom mixture cool for a few minutes, and then mix the mushroom mixture and the salmon in with the whisked eggs. Set oven to broil (high).

Warm a large iron skillet on the stove on medium-low heat, and add some more oil/butter. Pour the egg mixture into the skillet, top with cheese, and cook over low heat for a few minutes – without stirring. Once the bottom of the frittata has started to congeal, and stick to the pan – pull from the stove, and place under the broiler for about 3-5 minutes to cook the top half of the frittata.

Let cool for at least 5 minutes, and then slice for serving either warm or cold. Pairs nicely with a green salad and/or roasted root vegetables.

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Tips to Boost your vitamin D:

  1. Make your own vitamin D by getting outside every day between April and October. Our bodies can store vitamin D in our fat tissues, and we can draw on these reserves in the winter months.
  2. Ask your doctor to test your blood vitamin D levels if you are concerned about a possible deficiency.
  3. If you don’t consume seafood or dairy, you should consider keeping a supplement on hand, especially during the winter months. Liquid vitamin D drops are available in doses ranging from 400-2000 IUs per drop, and can be conveniently added to foods.
  4. The Tolerable Upper Intake Level (the maximum amount of vitamin D that is known to be safe to take each day) is 4000 IU for adults, and 3000 IU for children aged 4-8.
  5. See my recipe for A Very-Vitamin-D-licious Frittata!


More Resources on Vitamin D:




3 thoughts on “Digging for Vitamin D

Add yours

  1. Interesting read – particularly about mushroom increasing serum vit D as I was of the belief that their moderate D2 levels didn’t have much of an effect so found the article intriguing

    Liked by 1 person

    1. It’s safe to say that D3 is definitely more bio-available than D2, but that certainly doesn’t mean that the mushroom’s D-2 is useless. It’s kind of like how the heme-iron from beef is more bio-available than lentils, but that doesn’t mean we won’t get any benefit from the lentils’ non-heme iron…Thanks for the feedback, so glad that you “digged” the article!

      Liked by 1 person

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