Vitamin B12: Benefits, Deficiencies, and Food Sources

Jeux paralympiques

Vitamin B12 is a key nutrient for your well-being, playing a vital role in energy production, nervous system health, and the formation of red blood cells. However, it is often overlooked, especially in vegan or vegetarian diets. In this article, discover everything you need to know to avoid deficiencies: from essential benefits to food sources, as well as symptoms to watch out for. You will also learn how to diagnose and treat a deficiency, and why regular monitoring is essential. If you care about your health or athletic performance, this article is for you!

TABLE OF CONTENTS

MAIN BENEFITS OF VITAMIN B12.

Vitamin B12, or cobalamin, is a water-soluble vitamin that plays a fundamental role in many vital functions of the body. It is particularly important for maintaining a healthy nervous system, adequate production of blood cells, and optimal metabolism. Here is a detailed look at the main benefits of vitamin B12:

1. RED BLOOD CELL FORMATION

One of the most important roles of vitamin B12 is its involvement in the production and maturation of red blood cells. Vitamin B12 works together with folic acid (vitamin B9) to promote proper division and maturation of blood cells in the bone marrow. A deficiency in vitamin B12 can lead to inefficient red blood cell production, resulting in megaloblastic anemia. This type of anemia is characterized by red blood cells that are too large and immature, which reduces the efficiency of oxygen transport in the body and causes fatigue and general weakness.

2. NERVOUS SYSTEM FUNCTION

Vitamin B12 is crucial for the proper functioning of the nervous system. It plays a key role in the production of myelin, which protects nerves by forming their sheath. This sheath allows for efficient transmission of nerve signals. Without enough B12, myelin production is impaired, which can lead to nerve problems such as pain, tingling, or numbness in the limbs, memory and concentration issues, and symptoms of depression.

B12 also contributes to the production of neurotransmitters, the chemical substances that transmit nerve signals, which play a role in regulating mood and mental well-being. A B12 deficiency can therefore affect mood, with increased risks of mood disorders such as depression or anxiety.

3. DNA SYNTHESIS

Vitamin B12 plays an essential role in the production of DNA, the molecule that carries the genetic information necessary for cell division. Without sufficient B12, DNA production is disrupted, which can lead to errors in cell division. This can have serious consequences, including disrupting the production of blood cells (red and white) and tissue repair.

Vitamin B12 is therefore fundamental for cell regeneration and maintaining tissue health. It is essential for optimal growth and cell renewal, particularly in tissues with a rapid turnover such as skin, hair, nails, and even gastrointestinal tissues.

4. REDUCING FATIGUE AND EXHAUSTION

One of the most recognized benefits of vitamin B12 is its ability to help reduce fatigue and combat exhaustion. Vitamin B12 is involved in energy production at the cellular level by facilitating the conversion of carbohydrates and fats into energy in the form of ATP (adenosine triphosphate). This action helps maintain a stable energy level throughout the day.

When the body lacks vitamin B12, it can experience persistent fatigue, difficulty concentrating, and a general feeling of exhaustion. Supplementing with B12 can help restore energy and improve daily performance, which is especially beneficial for those with an active lifestyle or who suffer from chronic fatigue.

5. IMPROVING CARDIOVASCULAR HEALTH

Vitamin B12 also plays an important role in regulating homocysteine levels in the blood. Homocysteine is an amino acid whose high levels can increase the risk of heart disease and stroke. B12, in combination with vitamins B6 and B9, helps break down homocysteine, thereby reducing the risks associated with elevated levels.

In summary, vitamin B12 is essential for many vital functions of the body, such as blood cell production, nervous system health, DNA synthesis, energy generation, and maintaining cardiovascular health. Ensuring a sufficient intake of vitamin B12 is therefore crucial to prevent deficiency risks and maintain overall good health.

VITAMIN B12 DEFICIENCY: SYMPTOMS AND RISKS.

Vitamin B12 is essential for many vital bodily functions, and a deficiency can have serious health consequences. Due to its crucial role in red blood cell production, nervous system health, and DNA synthesis, a vitamin B12 deficiency can cause various symptoms and health complications, both in the short and long term. Here are the common symptoms and risks associated with vitamin B12 deficiency:

1. MEGALOBLASTIC ANEMIA

One of the most common symptoms of vitamin B12 deficiency is the development of megaloblastic anemia. This form of anemia is characterized by insufficient production of normal red blood cells, which are needed to carry oxygen in the blood. The red blood cells become larger and immature, impairing their ability to perform their function. This deficiency can cause persistent fatigue, pale skin, and shortness of breath.

Anemia symptoms may be mild at first, but as the deficiency progresses, the effects become more pronounced, with breathing difficulties, muscle weakness, and dizziness.

2. NEUROLOGICAL DISORDERS

Vitamin B12 is essential for nervous system health, and prolonged deficiency can have serious neurological effects. The degradation of myelin, the substance that protects nerves, is impaired in cases of B12 deficiency. This can cause symptoms such as:

  • Tingling and numbness in the hands, feet, and legs
  • Coordination and balance problems
  • Memory problems and mental confusion
  • Loss of sensation in certain parts of the body



Nerve damage due to vitamin B12 deficiency can be reversible if the deficiency is treated quickly. However, an untreated deficiency over a long period can lead to irreversible nerve damage, with risks of partial or complete paralysis in severe cases.

3. PERSISTENT FATIGUE AND MUSCLE WEAKNESS

One of the most common symptoms of vitamin B12 deficiency is chronic fatigue. Vitamin B12 is essential for cellular energy production, notably by helping convert carbohydrates and fats into energy. When B12 is lacking, this energy production decreases, leading to persistent fatigue and exhaustion. People with this deficiency may also experience muscle weakness, difficulty performing simple physical tasks, and slower recovery after exercise.

This can affect daily performance and compromise individuals’ physical abilities.

4. DIGESTIVE DISORDERS

Vitamin B12 deficiency can also affect the digestive system:

  • Loss of appetite
  • Nausea and sometimes vomiting
  • Diarrhea or constipation



These digestive disorders are often linked to poor absorption of vitamin B12 in the intestine, which further worsens the symptoms.

5. INCREASED RISK OF MENTAL DISORDERS AND DEPRESSION

Vitamin B12 is involved in the production of neurotransmitters that regulate mood and cognitive functions. A deficiency can cause symptoms of depression, mood swings, and irritability. People with vitamin B12 deficiency are also more likely to suffer from cognitive disorders, such as difficulty concentrating, brain fog, and memory loss.

Studies have suggested that vitamin B12 deficiency may play a role in the development of psychiatric disorders, particularly in older adults. Mental health can deteriorate with prolonged deficiency, leading to symptoms such as anxiety, confusion, or even delusions in the most severe cases.

6. HIGHER RISK IN CERTAIN POPULATIONS

Certain groups of people are at higher risk of vitamin B12 deficiency due to dietary habits, medical conditions, or physiological factors:

  • Strict vegans and vegetarians: Vitamin B12 is mainly found in animal-based products. Vegans, who exclude these foods, are more likely to develop a deficiency if they do not consume B12-fortified foods or supplements.
  • Older adults: As we age, the absorption of vitamin B12 in the intestine may decrease due to reduced stomach acid production, making vitamin B12 less available for absorption.
  • Pregnant and breastfeeding women: Vitamin B12 needs increase during pregnancy and breastfeeding. If the mother is deficient, it can affect the health of the fetus or infant.
  • People who have undergone bariatric surgery: Individuals who have had stomach or intestinal reduction surgery may have difficulty properly absorbing vitamin B12, leading to a deficiency.

Vitamin B12 deficiency can lead to a variety of symptoms, ranging from anemia and fatigue to neurological disorders and mental health problems. It is essential to identify this deficiency quickly and adopt appropriate treatment to avoid serious complications. People at risk, such as vegans, older adults, pregnant women, and those who have undergone bariatric surgery, should be especially vigilant and consult a healthcare professional to monitor their vitamin B12 levels.

DIETARY SOURCES OF VITAMIN B12.

Vitamin B12, also called cobalamin, is an essential vitamin that the body cannot produce on its own. It must therefore be obtained through diet or supplementation. Unlike many vitamins, vitamin B12 is found almost exclusively in animal-based products. It is therefore crucial for people following a strict vegan or vegetarian diet to take extra precautions to avoid deficiency. Here are the main dietary sources of vitamin B12 available:

1. MEAT AND OFFAL

Meat is particularly rich in vitamin B12, especially organ meats such as liver and kidneys, which contain very high concentrations of this vitamin.

  • Beef liver: Beef liver is one of the most concentrated sources of vitamin B12. A small portion can provide far more than the recommended daily intake.
  • Kidneys: Beef and lamb kidneys are also very rich in vitamin B12, although they are often less commonly eaten.
  • Red meat: Beef, lamb, and pork are also good sources of vitamin B12. When consumed in moderation, these meats can help meet B12 needs.



Meat is therefore an excellent source for those who eat it, and absorption of this vitamin is even better when cooked simply, without excessive processing.

2. FISH AND SEAFOOD

Fish and seafood are exceptional sources of vitamin B12, appreciated not only for their nutritional benefits but also for their richness in omega-3 fatty acids. Here are some examples:

  • Clams: Clams are among the best sources of vitamin B12, containing extremely high amounts of this vitamin.
  • Oysters: They also provide a significant amount of vitamin B12 and are often eaten raw or cooked.
  • Mackerel and sardines: These fatty fish are rich in both B12 and omega-3, which are beneficial for cardiovascular health.
  • Salmon and tuna: Widely consumed in many cuisines, these fish also provide a good amount of vitamin B12.
  • Cod and halibut: These white fish are also very good sources of vitamin B12.



Seafood and fish are therefore essential in the diet for those who want to increase their B12 intake while benefiting from the other valuable nutrients they provide.

3. DAIRY PRODUCTS

Dairy products are also important sources of vitamin B12. Milk and its derivatives, such as cheese and yogurt, provide not only B12 but also calcium and protein, making them nutritious foods for maintaining bone and muscle health.

  • Milk: Whether whole, semi-skimmed, or skimmed, milk is a reliable source of vitamin B12.
  • Cheese: Cheeses like Swiss, Gouda, Cheddar, and Parmesan contain notable amounts of B12. Hard cheeses generally have higher B12 content than soft cheeses.
  • Yogurt: Especially plain or probiotic yogurt, which is also a good source of B12, while providing beneficial probiotics for gut health.



Dairy products are therefore a simple and common option for people who consume animal-based foods but may not eat meat or fish every day.

4. EGGS

Eggs are another moderate source of vitamin B12, with lower concentrations than meat or fish, but still enough to help cover part of daily needs. Vitamin B12 is particularly concentrated in the yolk, so it is important to consume the whole egg to get its full benefits.

  • Eggs: Especially free-range or organic eggs, which tend to have higher nutrient levels, including vitamin B12.



Eggs are therefore a good source of B12 for those who do not regularly consume meat or fish and are looking for a high-quality protein source.

5. VITAMIN B12-FORTIFIED FOODS

For people following a vegan diet, vitamin B12 can be difficult to obtain since it is naturally found only in animal-based products. However, there are B12-fortified food products, often enriched specifically for vegetarian or vegan diets. These fortified foods include:

  • Fortified cereals: Some breakfast cereals are enriched with vitamin B12, offering a convenient way to increase intake of this vitamin.
  • Fortified plant-based drinks: Soy, almond, or oat-based drinks are sometimes fortified with vitamin B12, making them an excellent alternative for those who do not consume dairy products.
  • Vegan meat substitutes: Some vegan products, such as soy burgers, vegan sausages, and seitan-based meat alternatives, are enriched with vitamin B12 to meet the nutritional needs of people avoiding animal products.



Fortified foods are therefore essential for vegans and can also be beneficial for those who simply wish to increase their vitamin B12 intake from non-animal sources.

The dietary sources of vitamin B12 are mainly of animal origin: meat, fish, dairy products, eggs, and certain seafood. These foods help meet daily vitamin B12 needs, a crucial element for red blood cell formation, nervous system health, and energy production. For people following a strict vegan or vegetarian diet, it is essential to rely on B12-fortified foods or take supplements to avoid a deficiency.

PRACTICAL TIPS.

Since vitamin B12 is essential for many vital functions, it is crucial to ensure sufficient intake, especially for at-risk populations. Here are some practical tips for effectively managing vitamin B12 levels in the body:

1. REGULAR MONITORING OF VITAMIN B12 LEVELS

Because vitamin B12 deficiency can cause serious health problems such as anemia, neurological disorders, and fatigue, it is advisable to regularly monitor vitamin B12 levels, particularly in those at higher risk. This includes:

  • Older adults: As we age, vitamin B12 absorption can decrease due to reduced production of stomach acid, which is needed for its absorption in the intestine.
  • Vegans and vegetarians: Diets that exclude animal products carry a higher risk of deficiency, as B12 is found mainly in animal-based foods.
  • Pregnant and breastfeeding women: Vitamin B12 needs increase during pregnancy and breastfeeding.
  • People who have undergone bariatric surgery: Changes to the gastrointestinal tract can impair B12 absorption.



Regular blood tests help measure vitamin B12 levels in the body and detect any deficiency before it causes serious complications. A healthcare professional may recommend these tests, especially if one or more risk factors are present.

2. VITAMIN B12 SUPPLEMENTATION

If a vitamin B12 deficiency is diagnosed, supplementation may be necessary to restore appropriate levels of this vitamin. It is essential to follow the advice of a healthcare professional before starting any supplementation, as excessive intake can have side effects in some cases.

Supplementation options include:

  • Tablets or capsules: Taken orally, these are often effective if the deficiency is not severe.
  • Vitamin B12 injections: Used in cases of significant deficiency or poor absorption, they allow for rapid effect.
  • Sprays or drops: Useful for those who have difficulty swallowing or prefer direct absorption.



Supplementation can be temporary or long-term depending on the severity of the deficiency. Medical follow-up is often necessary to adjust doses and maintain stable levels.

3. MAINTAINING A BALANCED DIET TO ENSURE ADEQUATE VITAMIN B12 INTAKE

The best way to ensure adequate vitamin B12 intake is to maintain a balanced and varied diet, including foods rich in this vitamin in your daily meals. Here are some practical recommendations for sufficient intake:

  • Consume animal-based products: Meat, fish, eggs, and dairy products are rich in B12, protein, and essential nutrients.
  • Include fortified foods: Cereals, plant-based drinks, or meat substitutes enriched with vitamin B12 are practical alternatives for vegans and vegetarians.
  • Dietary supplements: Useful in cases of dietary restriction or increased needs, to be considered in consultation with a healthcare professional.
  • Prioritize balanced meals: A variety of foods (meats, fish, vegetables, fruits, legumes, cereals) contributes to good B12 intake and overall health.

In summary, to ensure sufficient vitamin B12 intake, it is essential to have a rich and varied diet, regularly monitor B12 levels, and consider supplementation in case of deficiency. Actively monitoring this vitamin and adjusting diet or supplementation according to specific needs is fundamental to avoiding deficiency risks and supporting good health.

VITAMIN B12 AND SPORTS.

Vitamin B12 plays a crucial role in the body, especially for athletes, as it influences several aspects of physical performance and recovery. Since vitamin B12 is involved in energy production, red blood cell formation, and nervous system function, it has a direct impact on endurance, strength, and muscle recovery. Here’s how vitamin B12 can influence sports performance and why it’s important to have a sufficient intake to optimize results in sports:

1. ROLE IN ENERGY PRODUCTION

Vitamin B12 is essential for cellular energy production. It participates in nutrient metabolism, particularly carbohydrates and fats, to produce ATP (adenosine triphosphate), the main source of energy for cells. Athletes engaged in intense or prolonged physical activities have increased energy needs. A B12 deficiency can lead to lower energy levels, directly affecting performance, endurance, and the ability to sustain intense training.

Adequate vitamin B12 intake helps to maintain a constant energy level, which is essential for athletes, especially in resistance or endurance activities such as running, cycling, or team sports. It also helps prevent premature fatigue, a common issue among athletes lacking B12.

2. IMPROVING RED BLOOD CELL PRODUCTION AND MUSCLE OXYGENATION

One of the main functions of vitamin B12 is to promote the production of red blood cells, which transport oxygen to muscles and organs. Adequate vitamin B12 intake is crucial to ensure the blood can carry enough oxygen, which is essential during intense physical efforts.

In cases of deficiency, red blood cell production can be impaired, reducing oxygen delivery to the muscles and leading to muscle fatigue, shortness of breath, and decreased performance. Athletes with this deficiency may experience endurance problems and be unable to maintain high performance levels during training or competition.

3. SUPPORTING THE NERVOUS SYSTEM AND COGNITIVE FUNCTIONS

Vitamin B12 is also crucial for nervous system health. It participates in the production of myelin, which insulates nerves and allows rapid transmission of nerve signals. This is particularly important for athletes, as a healthy nervous system enables quick reactions, optimal coordination, and fast thinking—essential during competitions or in sports requiring rapid, precise movements.

Moreover, vitamin B12 helps maintain good cognitive function, which can be an asset for athletes, especially those who must stay focused for long periods (such as chess players or team sport athletes). A B12 deficiency can cause memory problems, mental confusion, and difficulty concentrating, thereby reducing overall performance.

4. MUSCLE RECOVERY AND INJURY PREVENTION

Vitamin B12 also plays a role in muscle recovery. After intense training, muscles need to repair the micro-tears that occur during physical exertion. Vitamin B12, by helping in cell regeneration and the production of new cells, can speed up recovery and help reduce muscle soreness after exercise.

A B12 deficiency can slow down the recovery process and increase the risk of injuries due to muscle fatigue. Athletes can therefore benefit from adequate vitamin B12 intake to promote rapid recovery and prevent excessive fatigue, allowing them to train more intensely and consistently.

5. PREVENTING MOOD DISORDERS AND MANAGING STRESS

Athletes, especially those training at a high level, can be subject to significant physical and mental stress. Vitamin B12 is involved in the production of neurotransmitters that regulate mood, such as serotonin and dopamine. A proper balance of these neurotransmitters is essential for maintaining a positive and focused mindset, which is crucial for sports performance.

A vitamin B12 deficiency can lead to mood disorders, irritability, anxiety, and symptoms of depression, which can negatively impact motivation and concentration. Maintaining adequate B12 levels can help better manage stress related to training and competitions, leading to more consistent performance and better emotional control under pressure.

Vitamin B12 is an essential nutrient for athletes, as it plays a key role in energy production, red blood cell formation, muscle recovery, and nervous system health. Adequate vitamin B12 intake is crucial for maintaining optimal performance levels, avoiding premature fatigue, supporting post-exercise recovery, and managing mental stress. Athletes, especially those following a vegan diet or with medical conditions affecting B12 absorption, should closely monitor their levels of this vitamin to maximize their sports performance.

HOW TO DIAGNOSE A VITAMIN B12 DEFICIENCY?

The diagnosis of vitamin B12 deficiency involves several steps to confirm the lack of this essential vitamin and assess its impact on overall health. A vitamin B12 deficiency can lead to various symptoms, ranging from fatigue to neurological disorders, making its diagnosis essential, especially for at-risk individuals. Here are the main methods used to diagnose vitamin B12 deficiency:

1. CLINICAL EXAMINATION AND SYMPTOM ASSESSMENT

The diagnosis usually begins with a clinical assessment, where the doctor reviews your medical history, symptoms, and eating habits. Some people may show signs of vitamin B12 deficiency that include:

  • Persistent fatigue
  • Anemia (paleness, shortness of breath)
  • Neurological issues: tingling, numbness, loss of coordination
  • Cognitive problems: difficulty concentrating, memory issues
  • Digestive issues: nausea, diarrhea, loss of appetite



The doctor will also look at risk factors that may increase the likelihood of deficiency, such as:

  • A strict vegan or vegetarian diet (excluding animal sources of vitamin B12)
  • Medical history such as Crohn’s disease, atrophic gastritis, or bariatric surgery
  • Medications that affect vitamin B12 absorption (proton pump inhibitors, metformin)



2. BLOOD TEST FOR VITAMIN B12

The blood test is the most common diagnostic method to assess vitamin B12 levels. The doctor will order a serum B12 test. Results can generally be interpreted as follows:

  • Normal values: usually between 200 and 900 pg/mL (depending on the laboratory)
  • Low values: levels below 200 pg/mL usually indicate a deficiency, though some cutoffs go up to 250 pg/mL



It’s important to note that blood levels may not always accurately reflect true vitamin B12 status, especially in cases of absorption problems.

3. HOMOCYSTEINE AND METHYLMALONIC ACID (MMA) TESTS

If the blood test results are inconclusive or the doctor wants to confirm the diagnosis, additional tests can be done:

  • Homocysteine: High levels of homocysteine in the blood can be a sign of vitamin B12 deficiency, as this vitamin helps break down homocysteine. Excess homocysteine can also increase the risk of cardiovascular disease.
  • Methylmalonic acid (MMA): The MMA test measures MMA levels in the blood or urine. High MMA levels are a more precise indicator of vitamin B12 deficiency, as MMA accumulates in the body when vitamin B12 is insufficient. This test is considered one of the most sensitive for diagnosing B12 deficiency, especially when deficiency is present but blood B12 levels appear to be in the normal range.



4. COMPLETE BLOOD COUNT (CBC)

The doctor may also recommend a CBC to detect megaloblastic anemia, which is typical of vitamin B12 deficiency. It also evaluates other blood parameters. Signs include:

  • Severe fatigue
  • Pale skin
  • Shortness of breath



The CBC can also reveal abnormalities in white blood cells or platelets, which may be affected by prolonged deficiency.

5. ADDITIONAL TESTS FOR ABSORPTION DISORDERS

In some cases, additional tests may be necessary to identify whether the problem lies in intestinal absorption of vitamin B12, particularly after bariatric surgery or in cases of digestive disorders such as Crohn’s disease. One commonly used test was the Schilling test, although it is no longer widely used today due to advances in blood and urine testing.

6. DIETARY ASSESSMENT AND RISK FACTORS

Assessing dietary habits is another important aspect of diagnosis, as it can indicate dietary-related vitamin B12 deficiency. People following a strict vegan diet, for example, are often at risk, as vitamin B12 is found mainly in animal-based products. In such cases, the doctor may recommend B12 supplementation, either through fortified foods or supplements.

The diagnosis of vitamin B12 deficiency is based on a combination of clinical assessments, blood tests, and other diagnostic examinations. If you experience symptoms of deficiency or belong to a risk group (vegan, older adult, absorption issues), it is crucial to consult a healthcare professional for an accurate diagnosis and appropriate treatment. Early detection and treatment of vitamin B12 deficiency can prevent serious complications, such as neurological disorders and severe anemia.

WHAT ARE THE CAUSES OF A VITAMIN B12 DEFICIENCY?

Vitamin B12 is an essential nutrient that the body cannot produce on its own. It must be obtained through diet or supplements. A vitamin B12 deficiency can be caused by several factors, including dietary insufficiency, absorption disorders, or the use of certain medications. Identifying the underlying cause is important to effectively treat this deficiency. Here are the main causes of vitamin B12 deficiency:

1. INSUFFICIENT VITAMIN B12 INTAKE (PARTICULARLY AMONG VEGANS)

Vitamin B12 is found mainly in animal-based products. Meat, fish, dairy products, and eggs are naturally rich in vitamin B12. Therefore, insufficient dietary intake of vitamin B12 is a common cause of deficiency, especially in certain populations.

  • Strict vegans and vegetarians: at high risk of deficiency if they do not consume fortified foods or supplements.
  • Vegetarians: at moderate risk, especially if they consume little or have poor absorption of dairy products or eggs.



In this case, prevention involves regular consumption of B12-fortified foods (such as fortified plant-based drinks or cereals) or taking dietary supplements to avoid deficiency.

2. ABSORPTION DISORDERS RELATED TO MEDICAL CONDITIONS

Certain medical conditions affect the body’s ability to properly absorb vitamin B12 from food. These disorders may be caused by chronic diseases, infections, or digestive issues, including:

  • Crohn’s disease: A chronic inflammatory bowel disease that can interfere with nutrient absorption, including vitamin B12. It can particularly affect the part of the small intestine where vitamin B12 is absorbed, leading to deficiencies.
  • Atrophic gastritis: A condition characterized by inflammation and thinning of the stomach lining, reducing the production of intrinsic factor—a protein necessary for vitamin B12 absorption. Without enough intrinsic factor, the body cannot properly absorb vitamin B12, even if dietary intake is adequate.
  • Short bowel syndrome: People who have undergone bariatric surgery or partial intestinal resection, which reduce the length of the intestine, may have difficulty absorbing nutrients, including vitamin B12, increasing their risk of deficiency.
  • Parasitic or bacterial infections: Certain infections can disrupt the intestinal bacterial balance, which can interfere with vitamin B12 absorption.



These conditions often require specific supplementation (oral or injectable) depending on the severity of the deficiency.

3. LONG-TERM USE OF CERTAIN MEDICATIONS

Certain treatments can impair vitamin B12 absorption if taken over a long period:

  • Proton pump inhibitors (PPIs): PPIs are medications used to treat conditions such as gastroesophageal reflux disease (GERD) or gastric ulcers. They work by reducing stomach acid production. However, stomach acid is necessary to release vitamin B12 from food so it can be absorbed in the intestine. Long-term PPI use can therefore reduce vitamin B12 absorption and lead to deficiency.
  • Antidiabetic medications (Metformin): Metformin, a drug commonly prescribed for people with type 2 diabetes, can also interfere with vitamin B12 absorption. Long-term metformin use has been associated with lower vitamin B12 blood levels.
  • Other medications: Certain other drugs, such as some acid-reducing medications, antacids, or broad-spectrum antibiotics, can also disrupt gut flora and vitamin B12 absorption.



People taking medications that may interfere with vitamin B12 absorption should be closely monitored by a healthcare professional and may require regular B12 testing and supplementation if necessary.

4. ADVANCED AGE

As people age, vitamin B12 absorption can decrease. This is due to a reduction in stomach acid and intrinsic factor production, both necessary for absorbing vitamin B12 from food. Older adults are also more likely to have chronic conditions or absorption problems related to other medical issues, which can worsen vitamin B12 deficiency.

Older adults may therefore be particularly at risk of vitamin B12 deficiency, even if they consume enough B12-rich foods. It is recommended that older adults regularly check their vitamin B12 levels and discuss with their doctor whether supplementation is needed.

The main causes of vitamin B12 deficiency include an insufficient dietary intake of vitamin B12, particularly among vegans, intestinal absorption disorders related to medical conditions, and prolonged use of certain medications. It is crucial to discuss with a healthcare professional if you have risk factors (diet, digestive disorders, medication use). Indeed, a vitamin B12 deficiency can lead to serious complications if not diagnosed and treated promptly.

CAN VITAMIN B12 BE OBTAINED FROM PLANT-BASED SOURCES?

Vitamin B12 is a crucial nutrient for many bodily functions, but it is found mainly in animal-based products. This raises an important question for people following a vegan or vegetarian diet: can vitamin B12 be obtained from plant-based sources? Here are the key points to understand about vitamin B12 in a plant-based diet.

1. VITAMIN B12 FOUND IN ANIMAL-BASED PRODUCTS

Vitamin B12 is produced by certain bacteria and is naturally found in animal-based products such as:

  • Meat (beef, pork, poultry)
  • Fish and seafood
  • Dairy products (cheese, milk, yogurt)
  • Eggs



These foods are considered the most natural and richest sources of vitamin B12, providing a form that the human body can easily absorb.

2. VITAMIN B12 IN PLANT SOURCES: SPIRULINA AND ALGAE

Certain algae, such as spirulina, are known to contain vitamin B12. However, their bioavailability for humans remains controversial.

  • Spirulina: Spirulina is often cited as a plant-based source of vitamin B12, but researchers have questioned its ability to provide a truly bioavailable form of B12—that is, one that the human body can use effectively. Some studies show that the vitamin B12 in spirulina may be in the form of analogue cobalamin, an inactive form that cannot be effectively utilized by the body.
  • Other algae: Other algae, such as chlorella and certain red algae, also contain forms of vitamin B12, but like spirulina, their absorption efficiency is questioned.



In summary, it is not recommended to rely solely on algae to meet your vitamin B12 needs.

3. VITAMIN B12-FORTIFIED FOODS: AN ALTERNATIVE FOR VEGANS

For vegans and vegetarians who do not have access to animal sources of vitamin B12, it is recommended to consume foods fortified with vitamin B12. Many vegan products today are enriched with vitamin B12 to help meet the needs of people excluding animal products from their diets. These fortified foods include:

  • Plant-based drinks (almond, soy, oat milk, etc.)
  • Fortified breakfast cereals
  • Vegan meat substitutes (soy-based burgers, etc.)
  • Fortified nutritional yeast (often used in vegan and vegetarian diets)



These products provide a reliable and convenient source of vitamin B12 for plant-based diets.

4. VITAMIN B12 SUPPLEMENTS: A NECESSITY FOR VEGANS

In a strict vegan diet, vitamin B12 supplementation is highly recommended. Available forms include:

  • Tablets and capsules
  • Sublingual tablets
  • Liquid sprays or drops



A healthcare professional can recommend the appropriate dose (daily or weekly) depending on the individual’s profile.

5. RISKS OF VITAMIN B12 DEFICIENCY FOR VEGANS

Without adequate intake, a B12 deficiency can lead to:

  • Persistent fatigue
  • Neurological disorders: tingling, numbness, loss of coordination
  • Cognitive problems: memory issues, confusion, depression
  • Megaloblastic anemia



Vegans who exclude all animal sources of B12 and do not consume fortified foods or supplements are particularly vulnerable to these symptoms. Long-term deficiency can cause irreversible nerve damage.

Although certain algae, such as spirulina, contain vitamin B12, the bioavailability of this vitamin for humans remains widely debated. It is therefore recommended for vegans and vegetarians to turn to foods fortified with vitamin B12 or to take supplements to avoid a deficiency. Vitamin B12 is essential for many bodily functions, and its deficiency can lead to serious complications, hence the importance of ensuring adequate intake, especially for those who do not consume animal-based products.

COACH'S TIPS

Supplementing with B12 can help you when experiencing fatigue after intense training sessions, especially if you no longer recover as quickly.

Don’t hesitate to include B vitamins in your supplementation! You can find vitamin B12 in the daily vitamin or in the Multivitamin Men's, the Multivitamin Women's and the Stress at QNT.

Yves Bondroit coach for QNT

Posted in: Our tips

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