What is rickets? Just the fact that so many people ask that question goes to show you how far we’ve come.
Before vitamin D fortification in foods like dairy milk became mandated by law, a relatively high percentage of infants were experiencing broken bones. Likewise in adults – especially the elderly – due to osteomalacia, which is similar to rickets but the name given when adults have the disease.
After this vitamin was discovered over a century ago in 1914, it was quickly discovered that there was correlation between rickets/osteomalacia and vitamin D levels in the blood.
Then in 1923 a biochemist figured out a way to trigger some foods to produce D by exposing them to UV light (like mushrooms, which have no D2 content beforehand).
Thanks to that invention, by 1945 rickets was considered eliminated in the United States (1).
In danger again?
Let’s consider the facts…
The popularity of veganism is a definitely good thing, but the bad thing is that those who are on a plant-based diet are consuming very few vitamin D food sources. Most fortified sources like dairy milk and eggs are obviously not eaten.
But it’s not just vegans, as omnivores are also getting less D. Simply put, no one has time to be outside.
About a half-century ago, a household may have consisted of one person working 40 hours per week, with plenty of time leftover for that person – and the rest of their family – to live life. Go to the store, the park, wherever.
Contrast that to now. Both spouses probably stare at a computer screen 10 hours per day for at least 5, maybe even 6 days per week. Time for errands? Ha! We only have time for Amazon Prime, not a trip to the store. As a result of these factors, many of us are not even in the sun 10 minutes per day.
And even the “10 minutes per day” requirement is a myth.
According to the NIH, we may need up to 30 minutes (2). Those with naturally darker skin (non-caucasians) and anyone wearing long sleeves needs more time than average for their skin to produce an adequate amount. Likewise for the elderly and those who are obese (and being that most Americans are now overweight, obviously that factor affects many).
And no, you can’t blame deficiency on living in Seattle, Boston, or Ohio.
Despite the constant sunshine, the Middle East has some of the highest vitamin D deficiency rates in the world (3). In Saudi Arabia up to 37% of the population is deficient. Not because the sun isn’t available, but because of a similar lifestyle as us.
If it’s that bad in Saudi Arabia, you can only imagine how it is in your location which actually experiences seasons!
But even if you do have time to be in the sun, it may not be a good idea to rely on that as your source. The American Academy of Dermatology’s official stance is that you should rely on vitamin D supplements and fortified foods instead of getting it from UV, which includes both natural sunlight and indoor tanning (4).
Skin cancer is the worst, but accelerated aging of your skin from the sun is a pretty bad side effect too!
Brittle bones may not be the only worry
Weak bones which are prone to fractures may be a more obvious symptom, at least if you’ve already encountered fractures. But there are a lot of not-so-obvious reasons why vitamin D may be the most underappreciated nutrient.
Over the years, studies have suggested that deficiency might be linked in some way to adversely affecting the following diseases and conditions:
- Autoimmune diseases – “a strong correlate for asthma, allergic rhinitis and wheezing” (5), multiple sclerosis (6), and as an anti-inflammatory, for Crohn’s disease and ulcerative colitis (7)
- Viral infections – higher risk of infections including the flu (8), the common cold (9), and HIV (10)
- Colon cancer – lower levels have been linked to risk of colon cancer (11) (12)
- Shorter lifespan – for the elderly, the use of vitamin D3 supplements have been found to correlate with longer life (D2 like that from vegan food sources did not show the same) (13)
- Cognitive decline – “deficiency is associated with a substantially increased risk of all-cause dementia and Alzheimer disease” (14)
- Mood and depression – the evidence for this is somewhat weak, but studies suggest it (15)
- Pregnancy complications – birth to small infants, preeclampsia (PE), and gestational diabetes mellitus (GDM) (16)
Even though findings from research are not the same as undeniable conclusive proof for something, at the very least, they are suggestions as to why you should probably pay more attention to maintaining healthy vitamin D levels.
Meat vs. vegan sources of D
The good news is that as a vegan, you’re not getting cholesterol or the types of advanced glycation end products exclusively found in meat (which by the way, are linked to cancer and signs of premature aging).
The bad news is that your primary source, which is vitamin D2, has been shown to be dramatically less effective than the animal-derived D3 in terms of bioavailability and absorption.
Officially, the government still counts an IU of D2 as being equivalent to an IU of D3. That fluke dates back to the 1930’s and still remains. For the full history of how it happened, check out our post on vitamin D2 vs. D3.
And unlike other issues, almost all scientists seems to be in agreement on the vitamin D2 absorption inferiority. For the most part, the only thing you see disagreement on is the conversion ratio or efficacy difference between the two.
A decade ago, The American Journal of Nutrition did an interesting opinion piece on the body of research and cited many sources of the conversion ratio being 4 to 1 (17). For example, 4 IU of D2 being required to equal the effect of 1 IU of D3 in the human body. The article claims:
“vitamin D2, or ergocalciferol, should not be regarded as a nutrient suitable for supplementation or fortification”
How much D do you need per day?
Since the US government still doesn’t count the value of D2 and D3 as being different, they only report an RDA for the umbrella category of vitamin D.
|Vitamin D Recommended Dietary Allowances|
|0–12 months*||400 IU (10 mcg)||400 IU (10 mcg)|
|1–13 years||600 IU (15 mcg)||600 IU (15 mcg)|
|14–50 years||600 IU (15 mcg)||600 IU (15 mcg)||600 IU (15 mcg)||600 IU (15 mcg)|
|51–70 years||600 IU (15 mcg)||600 IU (15 mcg)|
|>70 years||800 IU (20 mcg)||800 IU (20 mcg)|
|* Adequate Intake (AI)
Source: Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D (2010)
It even can be hard for omnivores and vegetarians to reach those amounts from diet, since by far the naturally highest food sources of vitamin D3 are fatty fish like tuna and salmon. Relative to those, most animal sources are significantly lower. Meats provide small amounts. An 8 ounce vitamin D fortified dairy milk is only 115 to 124 IU. Products made from dairy like cheese and ice cream typically aren’t fortified (18).
If you’re getting all of your dietary vitamin D exclusively in the D2 form, you should ask your doctor if perhaps you should be taking higher amounts.
With all those caveats out of the way, let’s go through these
Top 10 vegan sources of vitamin D
For the most part, those on pure plant based diets will heavily rely on mushrooms as a food source for this nutrient.
Unfortunately the most common mushrooms are a terrible source. According to the USDA’s National Nutrient Database, 1 cup of diced portabella contains only 9 IU. For white button, it’s 5 IU and for crimini, it’s 2 IU.
You probably don’t want to eat 120 cups of white ‘shrooms to reach the RDA of 600 IU!
Luckily a couple more exotic species have exponentially higher amounts. You probably can’t stroll into your local Whole Foods and buy these fresh, but you can buy them online for reasonable prices in the dried form (that’s what the vegans here at Superfoodly do).
What do maitake taste like? Many describe them as having a spicy apple flavor. However what’s really unique about their flavor is that it contains L-glutamate, which has been described as “the 5th taste” since it stimulates certain receptor nodes on your tongue which most foods normally don’t affect. The sensation is the same as that after-taste you get from dry champagne.
Maitake is by far the best plant source. 1 cup diced (70 g) contains 786 IU of vitamin D2 and is only 22 calories, when measured fresh or reconstituted with water. Whole dried as well as ground powder supplements are sold online.
The second best is the morel, but it is a distant second: 136 IU in a 1 cup (66 g) serving when fresh.
These are another variety that aren’t normally sold at grocery stores. Like maitake (and most mushrooms for that matter) make sure you cook them thoroughly. They can be quite hard to digest if undercooked, causing stomach aches and other digestive issues.
Their taste is bland but still woodsy. If you don’t like the taste of common mushrooms like portabella, then you probably won’t like the flavor of morel since it’s even more earthy.
The 3rd best source is the chanterelle. Also one you are unlikely to find at the supermarket.
The highest quality golden chanterelle can cost you a lot, upwards of $80 or more per pound dried. It’s definitely not a cost effective way of getting vegan vitamin D. The flavor can be described as mild but with a slight bit of earthy spice to it.
1 cup (54 g) contains 114 IU and is 21 calories.
No, not the seafood. The fungus! With a mild and velvety texture, the taste of oyster is comparable to white button mushrooms.
This is the highest “normal” mushroom and its vitamin D content is a far cry versus maitake. 1 cup (86g) only contains 25 IU of vitamin D2. For that reason the mushroom powder supplement you see for sale in nutrition stores is a bad idea.
Sure at 28 calories for that size, in theory you could just eat a lot. But if you choose to do that, let us know how awful your stomach feels after!
Next up is that one that sounds like a swear word. Common in Asian cuisine, they have a spongy texture and a taste that is described as being meaty and woodsy.
Even well cooked shiitake can be hard to digest so when serving sizes are referenced, no one talks about them in a one cup increment. The USDA nutrient database lists the serving as 4 mushrooms (15 g dried) which offers 23 IU and 44 calories.
What will be of more interest to vegans is some controversial research which claims shiitake has a pseudo form of vitamin B12 that is bioavailable to humans.
This one is such a scientific anomaly, it’s worth mentioning for that reason alone. Even though it is a natural vegetarian source of vitamin D, it’s not a viable food source for humans.
Over 30 years ago research was done which discovered that the alfalfa plant (Medicago sativa) could be grown in the field and then irradiated with UV light to stimulate the production of D (19).
Not a big deal, right? Same thing as mushrooms! But not quite…
Field-grown alfalfa exposed to the sun was found to contain 1920 IU of vitamin D2 per kilogram (2.2 lbs). But that’s not the biggest surprise. Is there a vegan vitamin D3 source? It turns out there is one pure plant (non-fungus) that is. The tests showed that same amount of alfalfa contained 25 IU of D3!
How does alfalfa make D3 or where is it coming from? No one can say for sure, though it appears to be producing it internally. Another explanation may be a symbiotic bacteria which lives and grows on the hay which is responsible for creating its content.
Then should go out and graze in the field with the cattle? Nope.
There are good reasons why alfalfa is not a human food. Alfalfa seeds contain large amounts of canavanine, a toxic amino acid. Excess consumption can cause deterioration of your blood platelets through a condition called pancytopenia (20). Occasional alfalfa sprouts on your salad or sandwich are probably fine, but don’t make a habit of eating the seeds regularly.
Plus, the vitamin D measurements were for the hay/straw and not the seeds or sprouts.
We opt for other varieties, since systemic lupus erythematosus (SLE) has been induced in monkeys using alfalfa sprouts (21). Meanwhile the hay has high levels of saponins, which can reduce the absorption of minerals like iron.
In short, alfalfa is not a vegan food source. Even if you were to ignore the health dangers, eating 2.2 lbs to get a measly 25 IU of D3 would be insanity. In theory, supplements could be made by extracting and purifying the vitamin from it, but as of 2016 no one is doing that. Probably because there’s another better source (see #10 below).
7. Fortified cereal
Some cereals have fortification of D, but most don’t.
The exclusively vegan line, One Degree cereals, does not have any fortification. It tends to be only the big brands that fortify, at least in some of their products.
General Mills’ Cheerios provides 60 IU per serving, which is 10% of daily value. You will probably want the regular variety without honey.
Kellogg’s Rice Krispies have 90 IU or 15% of daily value.
Kellogg’s Raisin Bran has 60 IU or 10% of DV.
Most use bone-charred sugar. That makes cereal feasible for some vegetarians and vegan diets, but certainly not a universal option for those abiding by the strictest definition.
8. Fortified non-dairy milk
Not all, but many almond milks and soy milks fortify with vitamin D2.
A good source is So Delicious Almond Plus because it provides 30% of your daily value as well as 5 grams of plant protein coming from peas. It does cost more than the non-protein versions.
While not available in every market, Good Karma Flax Milk is our number one choice. An 8 ounce serving provides you 25% of the daily value but the real unique benefit is that it contains 1,200 mg of omega 3 (ALA) since it’s made with flax seeds.
What are lichens? A combination of a fungi and a plant. They are actually two different types of organisms living together, that benefit from one other. Consisting of a fungus and an algae, they can frequently be found growing on rocks, trees, and wood.
There are more than 18,000 species in the world and some colonies are estimated to be 9,000 years old!
Normally they are not used for food. Many are poisonous, only some are edible. In a few cultures, edible species are considered a delicacy. Like the Cetraria islandica in Scandinavia and the Umbilicaria esculenta in Japan.
Many produce D. There are some types of reindeer moss (which are actually a lichen, not a moss) that could be considered a vegan vitamin D3 food. Yes, they produce the D3 as well as the D2 form (22).
Given the fact that they are not consumed as food (at least in the United States) and that about 94% of fungi are toxic, it would be dangerously bad for you to harvest and eat them yourself.
10. Vegan D3 supplements
After looking over the list, you will probably agree with the vegans here at Superfoodly that a vitamin D supplement would be the best way to make sure you get your RDA.
Normally D3 is made from lanolin, which comes from sheep’s wool. For that reason, up until recently, there was no such thing as a vegan vitamin D supplement for that form.
But now we have options. A couple companies are making supplements using it derived from lichens. They do cost more than the lanolin-derived version, but that’s not surprising given the demand for them is much smaller.
Here are a few of our favorites: