Researchers studied 72 healthy vegans in Germany to see if a daily supplement could improve their nutrient levels. Over 4 months, participants took either a special multivitamin or a fake pill (placebo). The supplement contained important nutrients that vegans often lack, especially vitamin B12. The results showed that the supplement significantly boosted B12 levels in the blood, which is important because vegans can’t get B12 from plant foods. However, the supplement didn’t make much difference for other vitamins like A, K, and folate, suggesting vegans may already be getting enough of those from their diet.

The Quick Take

  • What they studied: Whether a daily multinutrient supplement could improve vitamin and nutrient levels in people who follow a vegan diet
  • Who participated: 72 healthy vegan adults between ages 19 and 57 living in Germany. All participants were already eating a vegan diet and had no serious health problems
  • Key finding: A supplement containing 82 micrograms of vitamin B12 per day significantly improved B12 levels in the blood after 4 months. Other nutrients in the supplement (vitamins A, K, and folate) showed no significant improvement, suggesting vegans may already have adequate levels of these nutrients
  • What it means for you: If you’re vegan, a B12 supplement appears helpful and may be worth considering, especially since B12 is hard to get from plant foods alone. However, you may not need supplements for other vitamins if you’re eating a well-balanced vegan diet. Talk to your doctor about what’s right for you personally

The Research Details

This was a randomized controlled trial, which is one of the strongest types of scientific studies. Researchers divided 72 vegan adults into two groups randomly. One group received a daily multinutrient supplement for 4 months, while the other group received a placebo (a fake pill that looked identical). Neither the participants nor the researchers knew who was getting the real supplement or the fake one—this is called “double-blind” and helps prevent bias.

At the start and end of the 4-month period, researchers measured nutrient levels in the participants’ blood. They looked at vitamins A, B2, B12, K, folate, and choline. They also measured related substances in the blood that indicate whether these nutrients are working properly in the body.

The supplement contained specific amounts of each nutrient. The key ingredient was 82 micrograms of vitamin B12 per day, which is important because vegans cannot get B12 from plant sources—B12 naturally comes from animal products or fortified foods.

This study design is important because it removes guessing and bias. By randomly assigning people to groups and using a placebo, researchers can be confident that any differences between groups are due to the supplement itself, not other factors. The double-blind approach means participants couldn’t change their behavior based on knowing whether they had the real supplement, which could skew results.

This study has several strengths: it used a proper control group (placebo), was double-blind, and measured actual blood levels of nutrients rather than just asking people what they ate. The sample size of 72 is reasonable for this type of research. However, the study only lasted 4 months, so we don’t know about long-term effects. All participants were healthy vegans in Germany, so results might differ for vegans in other countries with different food availability or for vegans with health conditions

What the Results Show

The most important finding was that vitamin B12 levels improved significantly in people taking the supplement compared to those taking the placebo. Specifically, three different blood markers for B12 all showed improvement: serum B12, holotranscobalamin (a form of B12 in the blood), and a combined B12 indicator. This means the supplement successfully delivered B12 to the body in a form it could use.

Interestingly, the supplement did NOT significantly improve levels of vitamin A, vitamin K, folate, or choline. This suggests that healthy vegans eating a balanced diet may already be getting enough of these nutrients from plant foods. Vitamin A can come from orange and yellow vegetables, folate from leafy greens and legumes, and choline from nuts and seeds.

The researchers also measured vitamin B2 (riboflavin) and found no significant improvement, even though the supplement contained B2. This could mean vegans are already getting adequate B2 from foods like almonds, mushrooms, and fortified plant milks.

The study measured several other blood markers related to bone health (osteocalcin) and kidney function (related to B12 metabolism), but these showed no significant changes. This is actually good news—it suggests the supplement didn’t cause any unexpected effects on these systems. The researchers also looked at homocysteine levels, which can indicate B12 status, and while there was a trend toward improvement, it wasn’t statistically significant

Previous research has consistently shown that vegans are at risk for B12 deficiency because B12 is not naturally found in plant foods. This study confirms what many nutrition experts already recommend: vegans should take a B12 supplement or eat B12-fortified foods. The finding that other nutrients didn’t need supplementation aligns with other research showing that well-planned vegan diets can provide adequate amounts of most vitamins and minerals except B12. This study adds to growing evidence that B12 supplementation is the key nutritional concern for vegans, rather than a broad need for multiple supplements

The study only lasted 4 months, so we don’t know if benefits continue or change over longer periods. All participants were healthy adults in Germany, so results might be different for vegans in other countries, older vegans, or vegans with certain health conditions. The study didn’t look at whether people actually felt better or had more energy—it only measured blood levels. Additionally, the study didn’t track how well people followed the supplement routine or whether they were taking other supplements on their own

The Bottom Line

If you follow a vegan diet, consider taking a vitamin B12 supplement of around 80-100 micrograms daily. This recommendation has moderate to strong evidence support. You likely don’t need a broad multinutrient supplement if you’re eating a varied vegan diet with plenty of vegetables, legumes, nuts, and seeds. However, you should still ensure you’re eating enough calcium-fortified plant milks and getting adequate vitamin D (which is challenging for everyone, not just vegans). Consult with a doctor or registered dietitian to determine what’s right for your individual situation

This research is most relevant for people following a vegan diet. It’s especially important for vegans who don’t eat fortified foods regularly or who have limited access to B12-fortified products. Vegetarians who eat eggs and dairy may get enough B12 from those sources and might not need supplementation. People with certain digestive conditions that affect B12 absorption should definitely talk to their doctor. This study is less relevant for people eating omnivorous diets, as they typically get B12 from animal products

B12 levels in the blood can start improving within weeks of supplementation, but the study measured changes after 4 months. Most people won’t notice dramatic physical changes immediately—B12 deficiency develops slowly over time, and supplementation prevents future problems rather than creating sudden improvements. If you have symptoms of B12 deficiency (fatigue, numbness, brain fog), you might notice gradual improvement over several weeks to months of consistent supplementation

Want to Apply This Research?

  • Track daily B12 supplement intake with a simple yes/no checkbox. Set a daily reminder at the same time each day (like with breakfast) to take your supplement and mark it in the app. This helps ensure consistency, which is important for maintaining adequate B12 levels
  • If you’re vegan and not currently taking B12, add a daily B12 supplement to your routine. Choose a supplement form you’ll actually use consistently—options include tablets, sublingual (under-tongue) tablets, sprays, or fortified plant milks. Set a specific time each day to take it, like with breakfast, to build the habit
  • Track your supplement adherence weekly in the app. Every 3-6 months, note any changes in energy levels, mental clarity, or physical symptoms. While you won’t see blood test results in the app, consistent tracking helps identify patterns. Consider getting blood work done annually to check B12 levels with your doctor, and share those results with the app to monitor trends over time

This research summary is for educational purposes only and should not replace professional medical advice. The study shows that B12 supplementation may benefit vegans, but individual nutritional needs vary. Before starting any supplement regimen, consult with your healthcare provider or a registered dietitian, especially if you have existing health conditions, take medications, or are pregnant or breastfeeding. Blood tests may be needed to assess your individual nutrient status. This summary reflects one study; always consider the full body of scientific evidence and your personal health situation when making nutritional decisions.