Both vegans and omnivores should take vitamin D seriously, as deficiency is widespread, and the consequences can be severe. Vitamin D is one of the trickier nutrients to deal with, since, in addition to the hazards of deficiency, there are also adverse consequences to taking too much. As a fat-soluble vitamin, it gets stored by your liver, which is an excellent thing since this helps guard against deficiency. But excessive amounts aren’t quickly flushed from the body, and can accumulate to dangerous levels. In this respect, vitamin D is similar to iron, which your body also needs but is highly toxic if taken in excessive amounts.
The RDA is 400 to 600 IU daily for infants, children, and adolescents, or 600 to 800 IU for adults. While you can reach this amount by drinking fortified cow’s milk or fortified vegan milks, or from supplements, your actual needs may be higher than the RDA. So it makes sense to take a blood test to determine your current vitamin D level and then take appropriate action if warranted.
What exactly is vitamin D? This article answers that question, explains how it impacts your health, and wraps up with links to several inexpensive vegan D3 supplements.
What is Vitamin D?
Like all vitamins and essential minerals, vitamin D is classified as a micronutrient. That is, in order for your body’s cells to function properly, they require tiny amounts of each of these nutrients.
Vitamin D differs from other micronutrients because it’s actually a hormone, and it can be synthesized in the body when skin is exposed to sunlight. For most people, though, getting enough vitamin D without a dietary source isn’t practical and, in some cases, it’s not possible.
The Evolving Understanding of Vitamin D
Rickets, characterized by soft, bendable bones, was identified as far back as the mid-1600s. Not coincidentally, this was when much of the world’s population migrated from rural areas to cities and began working indoors. During this time, rates of rickets exploded, and millions of people suffered debilitating lifelong bone problems arising from bowed legs, knock-knees, and spinal curvature.
Once rickets was identified, science took about 250 years to figure out that it’s caused by acute deficiency of vitamin D.
The first significant progress came in the 1840s, when a doctor published research documenting that children living in rural environments suffered lower rates of rickets. By the 1890s, scientists determined that cod liver oil prevented rickets, although they had no idea what substance in the oil was responsible. We now know that sunlight exposure creates vitamin D and that codfish store substantial amounts of it in their livers.
Not until the 1920s, when chemists began exposing fats to UV radiation, was the stage set to identify vitamin D molecules. Groundbreaking work on this front won the 1928 Nobel Prize in Medicine. By the 1930s, both vitamin D2 (ergocalciferol) and D3 (cholecalciferol) were identified. Interestingly, after some time the scientific community recognized that it had botched its first effort to isolate vitamin D, leading to the abandonment of D1 as a designated form of this molecule.
Public Health Efforts to Boost Vitamin D Intake
By 1940, the persistent efforts of scientists across decades had handed society the means to eradicate vitamin D deficiency worldwide. We knew the two forms of vitamin D, how to produce it cheaply, and the approximate dosages required to prevent health problems. But the opportunity to disseminate this information and encourage the public to act appropriately was largely squandered—a missed opportunity that has remained unrectified.
The most important measure taken to reduce deficiency was carried out in developed countries during the 1940s, when governments enacted regulations requiring vitamin D fortification of milk. This was an ingenious idea, costing a pittance yet improving the vitamin D status of everyone who consumes dairy products. Tragically, this effort got off to a rocky start, when careless milk processors fortified at levels far in excess of standards. This led to well-publicized hospitalizations from vitamin D toxicity, which in turn caused some governments to ban such fortification. Today, nationwide fortification of milk only occurs in the USA, Canada, and a few Northern European countries.
Important though it was, milk fortification never had the potential to eradicate deficiency worldwide. After all, many people drink little or no milk. Plus, most people of East Asian and African heritage can’t even digest milk without taking a lactase supplement or having the milk’s lactose removed. Add to this the fact that dairy producers have been unreliable when it comes to fortifying milk, with vitamin D levels in milk shown to vary considerably and even wildly from one sample to the next. A 1992 study in The New England Journal of Medicine found that only 29 percent of tested milk samples contained 80 to 120 percent of the required vitamin D.
So, while milk fortification has spared millions of people from suffering rickets and the worst consequences tied to acute vitamin D deficiency, it hasn’t solved the problem of ensuring that every person takes in optimum amounts of this nutrient. Nearly a century after milk fortification began, vitamin D deficiency remains a persistent worldwide problem, although certainly on a less catastrophic magnitude than it would be without milk fortification. A study published in 2025 found broad insufficiency in 76 percent of the population, overall deficiency in 48 percent, and clinical or severe deficiency in 15 percent. It’s tragic that both mild and severe deficiency remain rampant worldwide, especially given the remarkable work scientists have done over the past century to shed light on the issue. Clearly, most of the world’s population has remained ignorant of the risks of deficiency, as well as what they can do to improve their vitamin D status.
Some evidence suggests that vegans have lower vitamin D intakes and, in some cases, lower blood levels of vitamin D than the general population. In some cases this is likely because they’ve stopped drinking fortified cow’s milk, and haven’t replaced it with another source of vitamin D. This is an easy mistake, but it’s also easy to add vitamin D back to your diet.
The Protective Effects of Vitamin D
Vitamin D promotes calcium absorption, helps maintain adequate blood levels of calcium, and is needed for bone growth and maintenance. It prevents rickets in childhood and, together with calcium, lowers risk for osteoporosis, a problem of weak and brittle bones that remains widespread and afflicts tens of millions of people—older women in particular. In the United States, 27 percent of women and nearly 6 percent of men over age 65 have osteoporosis. This figure is nearly identical to a study that measured osteoporosis rates worldwide.
Osteoporosis can lead to life-threatening consequences. In older people who suffer a hip fracture due to osteoporosis, mortality rates over the next three months jump to five to eight times those of comparably aged people who haven’t suffered a fracture.
Vitamin D is also being studied for a possible role in reducing risk for heart disease, cancer, and depression. Although the studies yield mixed results, there is evidence to suggest that vitamin D plays a role well beyond its effects on bone health.
How to Meet Your Vitamin D Requirements
For most of human history, vitamin D needs have been met through sun exposure since few foods are naturally rich in this nutrient. Today, the wide availability of supplements and fortified foods makes it easy to meet needs through diet.
Fortunately, most vegan milks are fortified with vitamin D at the same level as cow’s milk. In fact, in order to qualify for the USDA’s Child and Adult Care Food Program:
Non-dairy beverages must be nutritionally equivalent to milk and meet the nutritional standards for fortification of calcium, protein, vitamin A, vitamin D, and other nutrients to levels found in cow’s milk…
Unfortunately, many dairy alternatives, like vegan cheese and sour cream, commonly receive no vitamin D fortification.
Exposure to strong sunlight will also improve your D3 status. How much vitamin D a person makes depends on the season, latitude of where they live, skin tone, and age. Older people and those with darker skin tones need more exposure. So do people who live far from the equator.
Also, the UV rays that stimulate vitamin D production are conclusively linked to premature aging of the skin and to risk of skin cancer. Sunburns, tanning, and cumulative sun exposure over time all speed up skin aging and raise risk for cancer. And although sunscreen protects against skin damage, it also dramatically reduces the amount of vitamin D you receive from sunlight.
In winter months at temperate latitudes, the sun is so low in the sky that your skin won’t produce any vitamin D. On top of this, if you’re wearing thick layers of winter clothing, your vitamin D production will be essentially zero.
The best advice is therefore to use sunscreen or wear protective clothing when you’re exposed to strong sunlight and to rely on fortified foods or supplements for vitamin D. The World Health Organization recommends using sun protection when the UV index is above 3. Most weather apps include this information or you can download the SunSmart Global UV app.
The small inconvenience and expense of a standard blood work panel can provide valuable information on where your vitamin D levels currently stand. On a blood work panel, this level will be listed as 25-hydroxyvitamin D, 25-OH Vitamin D, Calcidiol, or just plain old vitamin D. If your level comes in below 30 ng/mL, discuss it with your doctor, who will likely advise you to bump up your vitamin D intake.
A blood work panel will also reveal your vitamin B12 status, which is another valuable piece of information for everyone eating plant-based diets. If you’re only getting blood work done once, the end of winter is the best time to see your status at its most likely low point, since it’ll reflect a period when you’ve had little sunlight exposure.
Vegan Vitamin D Brands
Cow’s milk and breakfast cereals are fortified with vitamin D3, also called cholecalciferol, which is typically derived from the lanolin in sheep’s wool. Fortified plant milk usually contains vitamin D2 or ergocalciferol, which is derived from yeast and is vegan. Both types of vitamin D are also available as supplements. If you have adequate blood levels of vitamin D, either type of supplement seems to be effective for maintaining good vitamin D status. If you’re taking a higher dose of vitamin D to reverse a deficiency, D3 may be more effective. Unfortunately, most vitamin D supplements are not vegan. Until recently, nearly every brand was produced from lanolin, a non-vegan byproduct of the wool industry. When exposed to ultraviolet light, lanolin’s oils transform into a type of vitamin D called cholecalciferol. This molecule is better known as vitamin D3.
For years, vegans were stuck taking a more expensive and much less potent supplement containing ergocalciferol, commonly called vitamin D2.
Some time around 2010, supplement companies started producing vegan vitamin D3 from a type of algae called lichen. There are now many vegan vitamin D3 brands on the market:
- Deva: Vegan Vitamin D3 (5000 IU)
- Doctor’s Best: Vegan D3 Veggie Caps (2500 IU)
- Naturelo: Vitamin D3 Capsules (2500 IU)
- Igennus: Vegan Vitamin D3 (1000 IU)
- Revly: Vegan Vitamin D3 (2000 IU)
- Sports Research: Plant-Based Vegan Vitamin D3 (5000 IU)
Of the above products, Igennus’ Vegan Vitamin D3 delivers the best bang for the buck. For most people, one tablet daily should provide a sufficient dose. The 365 tablets per bottle give you a year’s supply at a very reasonable price.
