Can Not Eating Meat Cause B12 Deficiency?

October 20, 2025 •

3 min read

According to the National Institutes of Health, vitamin B12 is primarily found in animal products, meaning individuals who do not eat meat, fish, or dairy are at a higher risk of deficiency. This risk is especially prevalent for vegans, though vegetarians may also be affected, making supplementation or fortified foods necessary to meet daily requirements.

Quick Summary

Individuals following a plant-based diet have an increased risk of vitamin B12 deficiency because this vitamin is found naturally almost exclusively in animal products. Fortified foods and supplements are reliable sources to ensure adequate intake and prevent deficiency symptoms.

Key Points

Yes, Not Eating Meat Can Cause B12 Deficiency: Vitamin B12 is found naturally almost exclusively in animal products, making vegans and vegetarians who don't supplement at a higher risk.
Fortified Foods are Key: Many plant-based products, like nutritional yeast, cereals, and plant milks, are fortified with reliable, synthetic B12 to help meet dietary needs.
Supplements are a Reliable Choice: For guaranteed intake, B12 supplements in tablet, sublingual, or spray form are widely available and effective for vegans and those with absorption issues.
Symptoms are Varied and Gradual: Deficiency symptoms like fatigue, numbness, memory problems, and mood changes can take years to appear, as the body stores B12.
Regular Monitoring is Recommended: Individuals on a strict vegan or vegetarian diet should consider regular blood tests to monitor B12 levels and ensure adequate intake.
Not a Plant-Based Hoax: Claims that B12 can be reliably obtained from soil, specific algae, or fermented foods have been largely debunked by scientific research.

The Connection Between Meat and Vitamin B12

Vitamin B12, also known as cobalamin, is a crucial nutrient for the body's nerve and blood cells, as well as for making DNA. The human body cannot produce B12 on its own, so it must be obtained from external dietary sources. Naturally, vitamin B12 is synthesized by microorganisms, which are consumed by animals. As a result, B12 is concentrated in animal-based foods, making meat, fish, eggs, and dairy products reliable sources for omnivores. For this reason, individuals who eliminate these food groups, especially those following a strict vegan diet, must be proactive in finding alternative sources of B12.

Why Vegans and Vegetarians Are at Risk

While it is often assumed that a well-rounded plant-based diet is sufficient for all nutritional needs, B12 is the notable exception. Because plant-based foods do not naturally contain the vitamin in a form that humans can reliably absorb, vegans and, to a lesser extent, vegetarians, are at a higher risk of developing a deficiency. Vegetarians who consume eggs and dairy may have a lower risk but can still be affected, especially if their intake of these products is low. It is also a misconception that plants grown in rich soil or fermented foods like tempeh or certain types of algae can provide a reliable source of B12; decades of research and vegan experimentation have debunked these claims.

How to Prevent B12 Deficiency Without Meat

Avoiding B12 deficiency on a meatless diet is very manageable with proper planning. The most reliable vegan sources of B12 are fortified foods and dietary supplements.

Fortified Foods: Many common foods are fortified with synthetic B12, which is just as effective and bioavailable as the naturally occurring version. Examples include fortified nutritional yeast, plant-based milks (soy, almond, rice), breakfast cereals, and some meat substitutes.
Supplements: For many, supplements are the most convenient and reliable way to ensure adequate intake. B12 supplements are available in various forms, including tablets, chewables, liquids, and sublingual options that dissolve under the tongue. For individuals with severe deficiencies or absorption issues, injections may be necessary. Individuals following a meatless diet should consult with a healthcare professional to determine appropriate supplementation strategies to meet their individual needs.

Comparison of B12 Sources for Non-Meat Eaters


Source	Pros	Cons	Target Audience
Fortified Foods	Convenient, can be integrated into regular meals, good for meeting daily minimums.	B12 content can vary; requires label-checking; may not provide sufficient amounts for all.	Vegans and vegetarians aiming to top up B12 levels through diet.
Daily Supplements	Reliable and consistent intake, widely available, easy to remember.	Requires discipline to take daily; less ideal for those who prefer to rely on whole foods.	Vegans and vegetarians seeking a foolproof method for preventing deficiency.
Weekly High-Dose Supplements	Fewer instances of pill-taking, cost-effective in some cases.	Requires a high dose in one go; may not be suitable for those with sensitivities.	Vegans and vegetarians who prefer less frequent supplementation.

Symptoms of Vitamin B12 Deficiency

Symptoms of B12 deficiency can be gradual and may not appear for several years, as the body can store the vitamin in the liver. When symptoms do appear, they can be varied and often mimic other conditions, which is why B12 deficiency is sometimes called "the great masquerader".

Common symptoms include:

Fatigue, tiredness, and lethargy
Weakness and lightheadedness
Pale or yellowish skin (jaundice)
Neurological changes, such as numbness, tingling, or "pins and needles" in the hands and feet
Cognitive issues, including memory problems, confusion, and difficulty reasoning
Mood changes, such as depression or irritability
Shortness of breath and a rapid heart rate
Soreness of the mouth and tongue

Severe deficiency can lead to permanent nerve damage, so early detection and treatment are crucial. Regular blood tests to monitor B12 levels are recommended for those at risk.

Conclusion

Ultimately, the answer to the question, "can not eating meat cause B12 deficiency?" is a resounding yes. While a plant-based diet offers numerous health benefits, it does pose a significant risk for B12 deficiency due to the vitamin's natural scarcity in plants. Thankfully, this is an entirely manageable issue. By consistently incorporating reliable sources such as fortified foods and B12 supplements, vegans and vegetarians can easily meet their nutritional needs and avoid the serious health consequences of a deficiency. With informed planning, a meatless diet can be both healthy and complete. For more in-depth information on vegan nutrition, consult resources like The Vegan Society's guide to B12.

Frequently Asked Questions

Vitamin B12 is produced by microorganisms and is found naturally in animal products like meat, fish, eggs, and dairy, as these animals consume it from their environment or from fortified feed.

While eggs and dairy do contain B12, vegetarians who consume small amounts or have absorption issues may still be at risk for a deficiency. Supplementation or fortified foods can ensure adequate intake.

No, fermented foods like tempeh, as well as spirulina and most seaweeds, are not considered reliable sources of B12 for humans. The B12 content is often inconsistent or present in analogue forms that the body cannot use.

The body stores B12 in the liver, and these stores can last for several years. Therefore, it can take a long time, often years, for symptoms of a deficiency to become noticeable.

Symptoms can include fatigue, numbness or tingling in the hands and feet, memory problems, confusion, depression, pale skin, and anemia.

Yes, all vegans and those who consume very few animal products should take a B12 supplement. Fortified foods are also a good option, but a supplement provides a more consistent and reliable intake.

The B12 used in fortified foods and supplements is synthetic but is effectively absorbed and utilized by the body, making it a reliable source.