Vitamin D is known particularly for its effects on bone health. It maintains the body’s calcium and phosphate balance and improves the absorption of calcium in the small intestine1, 2. In addition, it plays a role in immunity regulation as well as the growth and differentiation of various cell types. The health effects of vitamin D are currently being widely researched.
Vitamin D is an essential nutrient only in geographical areas where the sun’s UV radiation is limited1. Our skin forms vitamin D when it comes into contact with the sun’s UV radiation. However, if there is not enough UV radiation throughout the year, vitamin D intake must be taken care of in other ways. Finland is one of these areas, which is why people living in Finland should make sure they are getting enough vitamin D.
Where do vegans get vitamin D?
Vegan food products are not good natural sources of vitamin D, as forest mushrooms are the only vegan food in which vitamin D occurs naturally3. Vitamin D is added into many fortified food products, such as margarines, vegetable oil-based spreads, as well as plant-based milks, yogurts, and quarks. Because vegans only get small amounts of vitamin D from their diet, it is important that they take it as a regular supplement2, 4, 5. A vitamin D supplement is necessary from the beginning of October to the end of March, when it cannot be obtained from sunlight. For those pregnant or breastfeeding, children between the ages of 0 and 17, as well as people over the age of 75, a year-round vitamin D supplement is recommended. Those following a vegan diet also benefit from a year-round supplement.
In food and supplements, vitamin D occurs in two different forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol)1. It was previously thought that vitamin D2 occurs in non-animal-based sources and vitamin D3 in animal-based ones. In recent years, however, vitamin D3 supplements suitable for vegans have entered the market, derived from lichen2. Most vitamin D3 supplements are made from the lanolin in sheep’s wool and are therefore not vegan. There are also small amounts of vitamin D3 in vegan DHA and EPA supplements, produced by microalgae.
Daily recommended intake of vitamin D
The Finnish and Nordic recommendation for overall intake of vitamin D is 10 µg per day, and for those over the age of 75, 20 µg per day. For as many people as possible to reach this overall intake, the nutritional recommendations advise eating fatty fish twice a week, as well as using fortified dairy products. If fatty fish and fortified dairy products are not consumed daily, using a vitamin D supplement is usually necessary. The recommended dose for the supplement is generally the same as the overall daily recommended intake.
However, there exist different recommendations for vitamin D, because there is no clear consensus among experts on sufficient vitamin D serum levels. Adequate intake of vitamin D is represented by vitamin D levels (25-(OH)-D levels) in blood serum. In Finland and other Nordic countries, > 50 nmol/l of 25-(OH)-D is considered a sufficient level for good health, and the Finnish recommendation for vitamin D intake is based on this. Some experts, however, argue that the target level should be 75 nmol/l6. This is why many vitamin D experts as well as experts on vegan nutrition specify higher amounts than the Finnish recommendation as the recommended daily intake: at least 20 – 25 µg2 7 8 9 10. The Endocrine Society recommends 38 – 50 µg per day6, and the Canadian Pediatric Society recommends 50 µg per day for pregnant people and 20 µg per day for babies that are exclusively breastfed11.
Using a strong enough supplement dose is especially important for vegans, because the vegan diet contains very few sources of vitamin D. According to a Finnish study, vegans got 34% less vitamin D from their diet than their cohorts on an omnivorous diet. In addition, 24% of vegans did not reach the recommended serum vitamin D levels, compared to only 6% in the omnivore group. In practice, this shows that without a vitamin D supplement, vegans are at a considerably greater risk of deficiency11. Taking a vitamin D supplement is safe as long as it does not exceed the upper limit for safe intake over a long-term period4 13 14. In pregnant people and infants, serum levels of 25-(OH)-D exceeding 125 nmol/l have been associated with slower growth in infants. In adults, levels exceeding 125 nmol/l have been shown to cause adverse effects to cardiovascular health16. These levels may be reached if the upper limit for safe intake is exceeded repeatedly. Table 1 shows recommendations for different age groups as well as the upper limits for safe intake. Because there is no scientific consensus on adequate vitamin D intake, we also do not give just one recommended amount, but instead a range based on recommendations from expert organizations in different countries4 6 11 15 16 17.
| Age groups and special cases | Recommended overall daily intake, μg | Upper limit for safe daily intake, μg4 13 14 |
| 0 – 6 m | 10 – 25 | 25 |
| 7-11 m | 10 – 25 | 35 |
| 1 – 10 y | 10 – 25 | 50 |
| 11 – 17 y | 10 – 25 | 100 |
| 18 – 74 y | 10 – 50 | 100 |
| ≥ 75 y | 20 – 50 | 100 |
| Pregnant people | 10 – 50 | 100 |
| Breastfeeding people | 10 – 50 | 100 |
You can get a blood test to determine your own vitamin D levels. The test should be done in the winter, when it shows whether you are using a sufficient vitamin D supplement. In the summer, time spent in the sun affects vitamin D levels.
Vitamin D supplements have important differences
Which form of vitamin D should be used as a supplement? Current scientific knowledge indicates that vitamin D3 functions more effectively in the body and is therefore the more recommendable option1, 19-24. In earlier studies, vitamin D3 has been more effective than vitamin D2 at large doses, whereas in regular doses, both forms have been equally well absorbed25. More recent studies have shown that vitamin D3 is preferrable also in conventional doses26. The efficacy of vitamin D supplements is determined by how much a certain dose can raise serum levels of 25-(OH)-D, the active form of vitamin D. According to one estimate, vitamin D3 may be 87% more effective at raising serum levels of 25-(OH)-D than vitamin D222.
The most important thing to remember when taking a vitamin D supplement is to take it regularly.
Vitamin D supplements suitable for vegans
Most vitamin D supplements on the market contain animal-based vitamin D. Supplements that are suitable for vegans are also available. Vitamin D is a fat-soluble vitamin, which means it is stored in the body4. This is why vitamin D can be taken as a single dose that is higher than the daily recommended intake, and the excess amount is stored for later use. Vitamin D supplements sold in Finland that are suitable for vegans include:
- Ainoa D3 (vitamin D3, 20 µg)
- Apteekin Oma Vegaanille (vitamin D3, 20 µg)
- Bioteekki Vegan D-vitamiini (vitamin D3, 75 µg)
- Devisol Vege (vitamin D3, 20 µg)
- Multivita Vegan (vitamin D3, 20 µg)
- MÖLLER Vegaani (vitamin D3, 10 µg + omega-3)
- Puhdas+ kapseli (vitamin D3, three different strenghts: 20 µg, 50 µg, and 100 µg)
- Sana-sol VEGAANI D-vitamiini (vitamin D3, two different strenghts: 25 µg and 50 µg)
- VEG1 (vitamin D3, 20 µg)
- Vegetology Multivit (vitamin D3, 5 µg)
When choosing a vitamin D supplement, you should look for products that contain vitamin D3. You can check this from the packaging of the product. NOTE: for example, the product Sana-sol Vegaani Monivitamiini contains vitamin D2 and is therefore not the best option for optimal vitamin D intake.
You can find nutritional information for different foods in the Fineli database maintained by the Finnish Institute for Health and Wellbeing.