What is vitamin D, and what makes it so important?

vegan vitamin d guide

Vitamin D is a fat-soluble vitamin that refers to a family of prohormones derived from cholesterol that plays an essential role in healthy bone maintenance and efficient calcium absorption.

Without it, the majority of the calcium we intake nutritionally wouldn’t be effectively absorbed, and much of it would be wasted

Originally thought to only play a part in calcium homeostasis with a function to support the intestine, kidneys, bone, and parathyroid gland, 

But alongside that, research has shown vitamin d plays a significant role in the immune system, insulin secretion, heart functioning, blood pressure regulation, and brain & fetal development.

Suffice it to say that its vitamin d is crucial and likely doesn’t get the notice that it should.

Benefits of vitamin D

  • Maintain and regulate calcium absorption
  • Maintenance of healthy teeth and bones
  • Support your cardiovascular health
  • Healthy lung function
  • Help to prevent cancers
  • Decreases the risk of hypertension,
  • Hep to prevent autoimmune diseases,
  • Help to manage diabetes through the regulation of insulin
benefits of vitamin d

But why is Vitamin D a potential problem for vegans, and are vegans the only ones at risk?

To answer this effectively, we first need to look at what things affect vitamin D levels where vitamin D comes from nutritionally and the two main types of vitamin d we need to focus on

Factors that affect vitamin D absorption

5 factors that affect vitamin d absorption

Vitamin D2 or D3

There have been multiple studies done on the effectiveness of vitamin d2 over d3 with conflicting results. 

Some research has shown that when taking regular 1000ui doses of vitamin D from either D2 or D3, the effects are equal 1,2,3.

Whereas other studies have shown that D3 is superior  with some results showing an overall 1.7 times better efficiency of vitamin D3 over D2

Some people have used the D2 to D3 argument as a means to discount plant-based sources of vitamin D since they mainly contain vitamin D2, but one of the most significant sources of vitamin D3 and a source that many of the fish high in vitamin D eat is a blue-green algae called Lichen.

The general takeaway for vegans is that the sources high in vitamin D, especially D3, are low. Mushrooms are a great source of vitamin D (mainly D2) and should be a high priority in a balanced vegan diet but a more effective way to manage vitamin D levels to gain bother D2 & D3 as a vegan is through extra sunshine, fortified foods, and supplementation 


For anyone lucky enough to live in a location that allows for relaxing strolls through the sun, where they can soak up the rays and getting a daily recharge of energizing vitamin d the chances of becoming deficient are extremely minimal. No matter whether you are vegan or non-vegan the sun is an optimal solution to any vitamin d issues

Sunlight obstruction

Multiple factors can prevent how much actual sunlight gets to your skin in a manner efficient enough for you to produce a healthy amount of vitamin D. From the season and time of day, through to clouds in the sky and glass windows they can all affect how much UV light you absorb but one of the biggest factors especially for those living in cities is pollution. 

The contaminated air, with smoke, fumes, car emissions, can prevent the number of UV rays that your skin absorbs which will affect how much vitamin D you can produce as a result.

skin tone

Skin tone

For melanated individuals that live in colder climates in the northern hemisphere, they will be more susceptible to vitamin d issues since those with more melanin in their skin can soak up more of the sun’s rays and therefore need more of it to hit a sufficient vitamin d amount. 

For those of us not living in daily beautiful weather conditions or for those who prefer to stay inside, your vitamin d will need to come from food.


Two issues arise with vitamin d and food. 

The first issue is that not many foods have a high amount of vitamin d content, so the struggle for anyone not living with enough sun becomes prevalent.

The second issue and the reason that there is a potentially higher risk for vegans is that the main food that has the highest amount of vitamin d content and is the most easily accessible is fish. 

But surprisingly still many fish and meat-eaters have a high rate of vitamin D deficiency, so concern over vitamin D is not strictly a Vegan issue

Fish contain the most amount of vitamin d simply due to the number of microalgae that they consume. The plants absorb the sun creating vitamin d which the fish consume, and when a meat-eater consumers the fish, the vitamin d continues on its path from to its next host, you. 

But the main focus there for any vegan should obviously be to notice that the plants are the first source of vitamin d so with that being said 

Which plants based foods have the highest vitamin d content for vegans to boost their vitamin d levels with?

Best vegan sources of VITAMIN D?

best vitamin d food sources

Plant-based foods naturally high in vitamin d

Mushrooms (shiitake, portobello, maitake, chanterelle, cremini)

Mushrooms exposed to sunlight or UV rays increases the amount of vitamin D contained within, making them one of the best sources of vitamin D on any diet.

Solanaceae family

Traditionally, only animal products have been considered a source of vitamin D3, but today we know that vitamin D3 and its metabolites are formed in certain plants. Accordingly, fruits and vegetables have the potential to serve as a source of vitamin D

Potato, tomato, pepper 


One of the main reasons fish are high in vitamin D is due to the microalgae that they eat. Microalgae is one of the only plant sources that we have identified so far that contain vitamin D3 instead of vitamin D2. 

The main microalgae that vegans should focus on are called Lichen.

Lichen is a cross between a fungus and an alga also known as cyanobacteria

Many places will also give it the name blue-green algae due to the similar properties that cyanobacteria and algae have

There are over 20,000 known species of lichen

Main uses of lichen:

  • dyes for wool and fabric
  • Ingredients in perfumes
  • Antibiotics and preservatives

And as we all know it can be used as the source of vitamin d3 in supplements (Link to top vitamin d3 supplements)

Vitamin D fortified foods for vegans

  • Fortified cereals
  • Fortified milk and yogurts (almond, soy, cashew)
  • Fortified juices (orange, tropical)
  • Sunlight 🙂

Most of the vitamin d in the standard American diet comes from fortified foods but without a big focus on the importance of vitamin D, there has still ended up being a high rate of vitamin D deficiency among the general public.

vitamin d supplementation

Vitamin D supplementation

A great way to hit your recommended daily amount is through a quality vitamin d supplement. In fact, the most efficient way for most individuals to get a consistently accurate amount of vitamin d daily is through supplementation. 

A high-quality vegan vitamin d supplement or a multivitamin containing vitamin D can help you keep your diet nutritionally balanced and effectively hit your recommended daily amount.

Lanolin vs Lichen (microalgae), and mushrooms.

Check out the best vegan vitamin d supplements available to find a product that works best for your needs.

How much vitamin d do vegans actually need?

The average recommended daily amount of vitamin D for both vegans and meat-eaters is 600iu but there are a few factors that can affect your requirement and absorption rate.

Vitamin D and Age

More information is constantly coming out, showcasing the importance of vitamin D and how it’s linked to a multitude of functions within the human body. 

Depending on your age, sex, and activity level, your required vitamin D levels will vary, but the average recommended daily amount of vitamin d is around 15micrograms, which is equivalent to 600iu (international units). 

This is enough to allow our bodies to absorb calcium without excess being wasted through urinary excretion.

As we get older, our ability to utilize vitamin D efficiently begins to decrease, so our vitamin d intake needs to increase for our bodies to maintain a healthy supply. 

For men and women above 70, the intake is increased by a third to 20 micrograms a day which is the equivalent of 800iu

Vitamin D and Weight

Bodyweight and fat amount are other factors that can play a part in how much vitamin D your body needs to run efficiently. 

A study in the European Journal of Nutrition found that the weight of participants had a 34.5% variation factor in the circulating vitamin D of those taking part, specifically when taking vitamin D in the form of supplements. 

The general conclusion was the more weight you have, the larger amount of vitamin D is needed for optimal levels to be reached

Vitamin D and Athletes

Due to supplementation growing in popularity, more and more people are turning to supplements as a solution to deficiencies. This is perfectly fine with the prerequisite requirements of knowing how much you need to be taking, how often, and what are the extreme levels that could potentially fall into overdose territory.

With athletes being one of the main groups marketed to when it comes to supplements, they can be prone to taking more than necessary to make sure they excel at their chosen sport. In regards to vitamin D, research shows no need to increase vitamin D intake when going through a rigorous exercise regime. The regular daily dosage given for the general public of 600-800iu per day is enough to hit most athletes needs according to the research 

The key take away is to make sure you get in enough to avoid deficiency, but no extra intake is needed to enhance performance.

Can you have too much vitamin D?

The upper intake level for vitamin D, according to the National Academies of Sciences Engineering and Medicine plus the European Food Standards Agency (EFSA) is 100mcg a day or 4000iu equivalent

Meaning this is the number that healthy adults can safely withstand without adverse side effects, but this does not mean this is the number you should be aiming for. 

Extreme amounts of vitamin D in the system have the potential to cause hypervitaminosis D which is rare but will usually result in symptoms such as

  • Nausea
  • low energy and fatigue
  • Weakness
  • loss of appetite

Since vitamin D plays a key role in the regulation and absorption of calcium, excess vitamin d can negatively affect calcium homeostasis and cause blood levels of calcium to rise which can potentially lead to calcification in the veins and muscle tissues 

Having an excess vitamin D usually occurs through oral means (such as supplementation) and doesn’t tend to occur due to extra time in the sun due since our bodies are able to self regulate our vitamin D levels.

How can I tell if I’m becoming vitamin D deficient?

signs of vitamin d deficiency

Vitamin D deficiency predominantly occurs as a result of dietary inefficiency. Since Vitamin D plays such an important part in so many of our bodily functions, it is important to be aware of some of the symptoms that could be linked to a possible deficiency.

If you notice any of these signs, consult your doctor.

Some symptoms to look out for:

  • Tiredness and fatigue
  • Bone pain
  • Muscle weakness
  • Depression
  • Diseases that can come from vitamin D deficiency are rickets and osteomalacia.
  • Weakened immune system

Vitamin D Cofactors

Cofactors are other sources other than the main nutrient (which in this case is vitamin D) that basically setup the right conditions in your body to allow for optimal and efficient absorption

Main vitamin D cofactors you should be aware of are

  • Vitamin K: Found in green leafy veg (Kale, Spinach, Mustard greens, Parsley) and vegetables such as broccoli cauliflower and brussels sprouts
  • Boron: Found in Apples, Dried fruit (prunes, raisins) Seeds & Nuts 
  • Zinc; Found in Legumes (chickpeas, lentils, beans) Nuts & Seeds, whole grains
  • Magnesium: Found in Spinach, Kale, Nuts & Seeds, legumes, bananas, and raspberries to name a few
  • Vitamin A: Found in carrots, sweet potatoes, Squash, Apricots, and Kale

Also, remember that vitamin d requires fat for optimal absorption since its an oil-soluble vitamin. 

The vegan vitamin D conclusion

  • The rates of vitamin D deficiency as a whole no matter whether you are vegan or meat-eater are high with many not hitting the RDA of 600iu
  • A plant-based diet does limit the amount of vitamin D3 sources available since the majority of plant-based sources of vitamin d are in the form of d2 (ergocalciferol) so its important to either gain more sun or supplement
  • Studies have suggested that vitamin d2 is not as efficient as d3 at increasing overall vitamin d levels in the blood
  • Alternative research has indicated that vitamin D2 and D3 are equivalent when taking a consistent amount daily (around 1000iu)
  • The issue with this data is that 1000iu is higher than the recommended daily amount so for consistency and safety a balanced dose (around 600iu) of d3 through supplementation/fortified foods and d2 through plant-based foods such as mushrooms, is likely the best route.
  • If you live in areas that have a lot of sunlight, don’t waste its rays. It is a good way to allow our bodies to create sufficient stores of vitamin d provided you don’t allow yourself to get cooked so use the sun wisely. The reality is not everyone lives in climates where they can get enough, and even those that do may not have the time or energy to frolic and chill to the point where they can safely get enough.
  • Overall there aren’t many natural food sources that provide large amounts of vitamin d no matter your diet.
  • The highest vitamin d3 content for vegans is found in Lichen, and the highest vitamin d2 content is found in mushrooms
  • Fortified foods and supplementation along with regular sun exposure are generally the best options to boost vitamin D levels along with a regular helping of some tasty mushroom

We hope at the end of all of this you feel more like a sunshine vitamin master and can leave knowing the steps to take to keep your overall vitamin D balanced as you progress on your health journey


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