What Vitamins Do Vegans Need?

Or: How to Not Fall Apart While Saving the Animals

It's a beautiful, crisp morning here in Helsinki. The sun is out, the birds are singing, and I am contemplating my own mortality. Specifically, I’m thinking about all the tiny, invisible things my body needs to not fall apart, and the very real possibility that I am getting none of them. This cheerful train of thought was triggered by my latest investigation into the world of veganism.

When a person announces they are going vegan, they are immediately met with a chorus of concerned, almost panicked, questions from their friends and family. "But what about protein?" they cry. "What about iron?" "Will your bones turn to dust?" It’s a nutritional interrogation. This widespread panic is fueled by a deep-seated fear that a diet without animal products is a one-way ticket to a sad, brittle, nutritionally bankrupt existence.

As an investigator of our modern anxieties, I wanted to find out if there was any truth to this. Is a vegan diet a minefield of potential deficiencies? Are there secret vitamins lurking in a steak that plants have selfishly decided to keep for themselves? Today, I’m launching a full-scale investigation to find out. We’re going to look at the science, debunk the myths, and create a definitive guide to the question: what vitamins do vegans need? 🧐

A Quick Word on Blame: It's Not the Plants' Fault

Before we dive into the specific vitamins, I think it’s crucial to establish one key principle. The nutritional challenges of a vegan diet are not, as some people seem to believe, a sign that the diet is "unnatural" or "wrong." They are, for the most part, a direct consequence of living in a weird, hyper-sanitized, modern industrial world.

For most of human history, we got many of these trace nutrients from our environment—from drinking out of streams, from eating unwashed plants with a bit of soil still clinging to them, and from living under a giant, unfiltered ball of fire called the sun. Our modern, indoor, chlorinated lifestyle has cut us off from many of these natural sources. So, the need for a little bit of planning and supplementation is not a failure of the vegan diet; it’s just a reality of being a 21st-century human who would rather not get cholera from their salad. 🥬

I was explaining this to my friend and he said that he gets all his essential nutrients from coffee and a profound sense of impending dread. I informed him that while dread is a powerful motivator, it is not, as far as science is aware, a recognized source of Vitamin B12. So, let’s look at the actual sources.

The Most Wanted List: A Vitamin-by-Vitamin Interrogation

My investigation has identified a handful of key vitamins that every person on a plant-based diet must be aware of. These are the ones that are either completely absent from plant foods or are a bit tricky to get in sufficient quantities. We are going to put each one under the interrogation lamp. 💡

Vitamin B12: The Undisputed King of "You Absolutely Must Supplement This"

This is the big one. If you take away only one piece of information from this entire way-too-many-words investigation, let it be this: vegans must supplement with Vitamin B12. This is not a suggestion. It is not a friendly piece of advice. It is a non-negotiable, universal, and incredibly important rule.

• What It Does (Its Motive): Vitamin B12 is the master electrician of your body. It is absolutely essential for the healthy function of your nervous system, as it helps to build and maintain the myelin sheath, the protective insulating layer that surrounds your nerves. It’s also crucial for forming red blood cells and for DNA synthesis. A deficiency doesn't just make you feel a bit tired; it can lead to severe and often irreversible neurological damage. We’re talking about things like memory loss, confusion, and permanent nerve damage. It is not something to be trifled with.

  
  

• The Problem (Its Opportunity): Vitamin B12 is not made by plants or animals. It is made by microorganisms, like bacteria and archaea.² Animals get it by eating food from the soil or from their own gut bacteria, and it accumulates in their tissues. In our modern, sanitized world, there are no reliable, unfortified plant-based sources of B12. The tiny amounts you might find on unwashed organic vegetables are not enough. The B12 found in some fermented foods or seaweed has been shown to be a B12 analogue, a sort of "imposter" vitamin that can actually block the absorption of the real thing.³

  
  

• The Solution (The Conviction): The solution is simple, cheap, and incredibly effective: supplementation. You can get all the B12 you need from a simple, once-a-week B12 supplement (a dose of around 2,500 mcg) or a smaller daily dose. You can also get it from consistently eating foods that have been heavily fortified with B12, like some plant milks, breakfast cereals, and nutritional yeast.⁴ But a supplement is the most reliable insurance policy. Ignoring B12 is not a neutral act; it is an act of profound self-sabotage.

  
  

Vitamin D: The Sunshine Scammer ☀️

This is a fascinating and deeply misunderstood vitamin. It’s often called the "sunshine vitamin," which makes it sound like a cheerful, happy-go-lucky nutrient, but my investigation revealed it’s more of a moody, unreliable friend who only shows up when it feels like it.

• What It Does (Its Motive): Vitamin D isn't really a vitamin; it functions more like a hormone. Its most famous job is to regulate calcium and phosphorus absorption, which is absolutely critical for bone health. Without enough Vitamin D, you can eat all the calcium in the world, but your body can't use it properly. But its job description doesn't stop there. It’s also crucial for immune function, mood regulation, and muscle health. Deficiency is linked to a higher risk of osteoporosis, depression, and autoimmune diseases.

  
  

• The Problem (Its Opportunity): The main way humans are supposed to get Vitamin D is by synthesizing it in our skin from UVB rays from the sun. The problem is that, for a huge portion of the world's population, this is practically impossible for much of the year. If you live anywhere north of about Los Angeles, the sun's rays are too weak in the winter months for your skin to produce any Vitamin D. Add to this the fact that most of us work indoors and wear sunscreen (a very good and necessary thing!), and you have a recipe for widespread deficiency. This is not a vegan problem; it’s a modern human problem. However, the few dietary sources of Vitamin D are almost all animal-based: fatty fish, egg yolks, and fortified dairy milk.

  
  

• The Solution (The Conviction): For most people, especially those of us enjoying the long, dark, and soul-crushingly beautiful winters here in Finland, a Vitamin D supplement is the only reliable answer. 🇫🇮 There are two main types of supplements: D2 (ergocalciferol), which is always vegan and derived from yeast or mushrooms, and D3 (cholecalciferol), which is traditionally derived from lanolin (the grease from sheep's wool) but is now also widely available in a vegan form derived from lichen. The vegan D3 is generally considered to be more effective.

Vitamin A: The Conversion Conundrum 🥕

This is a more subtle but equally important nutrient. Vitamin A is essential for vision, immune function, and skin health.

• What It Does (Its Motive): It’s a key component of rhodopsin, the pigment in your eyes that allows you to see in low light. It also plays a vital role in maintaining the health of your skin and mucous membranes, which are your body's first line of defense against infection.

  
  

• The Problem (Its Opportunity): Here's the tricky part. There are two types of Vitamin A. Preformed Vitamin A (retinol) is the active form that your body can use immediately, and it is only found in animal products. Plants, on the other hand, contain provitamin A carotenoids, the most famous of which is beta-carotene. These are the pigments that give fruits and vegetables their beautiful orange and yellow colors. Your body can convert beta-carotene into active Vitamin A, but this conversion process can be very inefficient for some people due to genetic variations.

  
  

• The Solution (The Conviction): For most vegans, the solution is not to supplement, but to eat an absolute mountain of carotenoid-rich foods. Don't just nibble on a single carrot; make sweet potatoes, pumpkins, butternut squash, mangoes, and dark leafy greens (like kale and spinach) a central and abundant part of your diet. By providing your body with a huge supply of the precursor, you give it the best possible chance of making what it needs.

Questions from the Internet: "Okay, you've terrified me. What is the bare minimum supplement a new vegan must take?"

An excellent and very practical question. If we're talking about the absolute, non-negotiable, "do-this-or-you-will-get-sick" bare minimum, my investigation points to just two things for the average adult vegan:

1. Vitamin B12: As we've established, this is not optional.

   
   

2. Vitamin D: For most people, especially those in less sunny climates, this is also effectively non-negotiable.

   Beyond that, other supplements like Iron, Calcium, or Omega-3s may be necessary depending on your individual diet and health status, but B12 and D are the universal requirements.

Questions from the Internet: "What about Vitamin K? I heard there are different kinds."

This is a fantastic question that shows a deep level of nutritional nerdiness, which I respect immensely. Yes, there are two main forms of Vitamin K.

• Vitamin K1 (phylloquinone): This is found in abundance in leafy green vegetables. Its primary job is blood clotting. It is very easy for vegans to get enough of this.

  
  

• Vitamin K2 (menaquinone): This is a bit more complicated. It seems to play a more important role in directing calcium to your bones and away from your arteries. It is primarily found in animal products and fermented foods. The best vegan source by a country mile is natto, a traditional Japanese dish of fermented soybeans that has a... shall we say, "acquired" taste and a texture that has been compared to alien mucus. 👽 If you are not a natto enthusiast, some research suggests our gut bacteria can convert some K1 into K2, but the efficiency is debated. For this reason, some vegan health experts now recommend a K2 supplement.

Internal Link Break!

A well-planned vegan diet, with its vitamin strategy sorted, has been shown in countless studies to have a profoundly positive effect on the body. For a comprehensive overview of how this way of eating impacts everything from your heart to your gut, you can read my full investigation here: [What a Vegan Diet Actually Does to Your Body].

The Conclusion: A License to Thrive

So, after this deep dive into the microscopic world of vitamins, what is my final verdict? What vitamins do vegans need?

My investigation has shown me that the vegan diet is not a magic bullet, but it is also not a nutritional minefield. It is simply a way of eating that requires a slightly different set of instructions. The widespread fear of vegan deficiency is, for the most part, a ghost story. The truth is that a diet built on an abundance of whole plant foods is a veritable powerhouse of most of the vitamins and minerals a human needs to thrive.

The few nutrients that are tricky to get are not a sign of the diet's failure; they are simply a puzzle to be solved. And the solutions are easy: eat your colorful vegetables, don't be afraid of a few key supplements, and for the love of all that is holy, take your Vitamin B12.

By following this simple, evidence-based roadmap, you are not just surviving on a vegan diet; you are giving yourself a license to thrive. ✅

Of course, getting your vitamins is just one part of the equation. Making sure you're getting enough protein is another huge topic of concern. I've debunked all the myths in that debate right here: [The Great Protein Panic: Do Vegans Get Enough, Or Are We All Secretly Disintegrating?].

Sources

• The Academy of Nutrition and Dietetics. Position Paper on Vegetarian Diets. (The key statement on safety and adequacy for all life stages).

• The National Institutes of Health (NIH), Office of Dietary Supplements. Fact sheets for Vitamin B12, Vitamin D, Vitamin A, and Vitamin K.

• The Vegan Society. Nutrition & Health. (Provides detailed information on key nutrients for vegans). https://www.vegansociety.com/resources/nutrition-and-health

• Jack Norris, RD. VeganHealth.org. (A comprehensive, evidence-based resource on vegan nutrition). https://veganhealth.org/

• The Vegan RD (Ginny Messina, MPH, RD). Vegan Nutrition Primers. (A collection of articles on key nutrients). https://www.theveganrd.com/vegan-nutrition-101/vegan-nutrition-primers/

• Healthline. 7 Supplements You May Need on a Vegan Diet. https://www.healthline.com/nutrition/7-supplements-for-vegans

• Physicians Committee for Responsible Medicine (PCRM). Nutrition for Adults. https://www.pcrm.org/good-nutrition/nutrition-for-adults

• Our World in Data. Micronutrient Deficiency. (For a global perspective on vitamin deficiencies in all diet types).