Vitamin B12 is essential for healthy red blood cells, normal nerve function and DNA production. Although deficiency can affect anyone, certain people are more likely to have low B12 levels because of their diet, age, medical conditions or medications.
Introduction
Vitamin B12 is one of the essential vitamins your body needs to function properly. It helps keep nerve cells healthy, supports the production of DNA and is needed to make healthy red blood cells.
Unlike some nutrients that can be obtained from a wide variety of plant foods, naturally occurring vitamin B12 is found mainly in animal-source foods such as fish, meat, poultry, eggs and dairy products. Some foods are also fortified with vitamin B12.
Your body can store vitamin B12 for a long time, so deficiency may develop gradually. This means a person can have low B12 levels for some time before obvious symptoms appear.
Recognising who may be at greater risk can help people discuss appropriate testing and treatment with a healthcare professional.
What Does Vitamin B12 Do in the Body?
Vitamin B12 performs several important functions.
It Supports Red Blood Cell Production
Vitamin B12 is involved in the formation of healthy red blood cells. When there is not enough B12, red blood cells can become unusually large and function abnormally, potentially leading to a type of anaemia called megaloblastic anaemia.
This can cause symptoms such as tiredness, weakness and reduced energy.
It Helps Keep the Nervous System Healthy
Vitamin B12 plays an important role in maintaining normal nerve function.
When deficiency becomes significant or prolonged, nerve-related symptoms can occur. These may include numbness, tingling, balance problems or changes in sensation.
It Is Needed for DNA Production
Vitamin B12 is involved in the production and maintenance of DNA, the genetic material found in your cells.
This is one reason why B12 is important for normal cell function and blood-cell production.
Who May Be at Risk of Vitamin B12 Deficiency?
Several groups have a higher risk of developing B12 deficiency.
1. People Who Follow a Vegan Diet
People who eat a strictly vegan diet may have a higher risk because natural vitamin B12 is found primarily in animal-source foods.
Plant foods do not naturally provide reliable amounts of B12 unless they have been fortified.
This does not mean a vegan diet is automatically unhealthy. However, people following a vegan diet need a reliable source of vitamin B12, such as appropriately fortified foods or a supplement recommended according to individual needs.
2. Older Adults
The risk of B12 deficiency can increase with age. Some older adults produce less stomach acid, which can make it more difficult for the body to release B12 from food and absorb it properly.
Some older people may also have digestive conditions or take medications that interfere with B12 absorption.
For this reason, persistent symptoms or risk factors should be discussed with a healthcare professional rather than simply being attributed to ageing.
3. People With Certain Digestive Conditions
Some medical conditions affecting the stomach or intestines can interfere with B12 absorption.
Conditions such as atrophic gastritis, pernicious anaemia and some disorders affecting the small intestine can make it difficult for the body to absorb enough B12.
People who have undergone certain gastrointestinal surgeries may also be at increased risk.
4. People Who Have Had Stomach or Intestinal Surgery
Some surgical procedures can alter the digestive system in ways that affect how nutrients are absorbed.
For example, certain weight-loss surgeries can reduce the body’s ability to absorb vitamin B12.
People who have undergone these procedures may need long-term nutritional monitoring and, in some cases, B12 supplementation.
5. People Taking Certain Medications
Some medications can interfere with vitamin B12 absorption. One example is metformin, a medication commonly used to manage type 2 diabetes. Long-term use has been associated with reduced B12 levels in some people.
Certain medicines that reduce stomach acid, including proton pump inhibitors and some H2-receptor antagonists, can also affect B12 absorption when used for prolonged periods.
This does not mean you should stop taking a prescribed medication because of concerns about B12. Instead, discuss your risk with your healthcare professional.
6. People With Pernicious Anaemia
Pernicious anemia is an autoimmune condition in which the body cannot absorb vitamin B12 properly because of a lack of intrinsic factor.
Intrinsic factor is a protein produced in the stomach that is needed for normal absorption of B12.
People with pernicious anaemia generally require medical treatment to correct the deficiency.
7. People Who Eat Very Little Animal-Source Food
You do not have to follow a completely vegan diet to have a low B12 intake. People who rarely eat meat, fish, eggs or dairy products may also have difficulty obtaining enough B12 unless they regularly consume fortified foods or another reliable source.
This can be particularly relevant when someone has a restricted diet for personal, cultural, financial or health reasons.
8. People With Poor Overall Nutritional Intake
People who regularly eat very little food or have a highly restricted diet may not obtain enough B12 and other essential nutrients.
Poor appetite, chronic illness, food insecurity and certain eating patterns can contribute to inadequate nutrient intake.
In these situations, the solution may involve addressing overall nutrition rather than focusing on B12 alone.
MUST READ: How Nutritional Needs Change as You Age
What Are the Signs of Vitamin B12 Deficiency?
B12 deficiency can develop slowly, and symptoms can vary from person to person.
Possible symptoms include:
- Persistent tiredness or weakness
- Pale skin
- Shortness of breath, particularly with activity
- Dizziness
- Headaches
- A sore or inflamed tongue
- Reduced appetite
- Numbness or tingling in the hands or feet
- Muscle weakness
- Problems with balance
- Memory or concentration difficulties
- Changes in mood
These symptoms are not specific to vitamin B12 deficiency.
For example, tiredness can result from anaemia caused by iron deficiency, sleep problems, infections, thyroid disorders and many other conditions. This is why symptoms alone cannot confirm a B12 deficiency.
Which Foods Contain Vitamin B12?
Vitamin B12 is naturally present in many animal-source foods. Good dietary sources include:
Fish and Seafood
Fish such as sardines, salmon, tuna and other seafood can provide vitamin B12 along with protein and other nutrients.
Meat and Poultry
Beef, chicken and other meats contain B12. Organ meats such as liver can contain particularly high amounts, although they should not necessarily be eaten frequently because of their very high vitamin A content.
Eggs
Eggs provide vitamin B12 and can be an accessible source for people who include animal products in their diet.
Milk and Dairy Products
Milk, yoghurt and some cheeses provide B12.
Fortified Foods
Some plant-based milk alternatives, breakfast cereals and nutritional products are fortified with vitamin B12.
If you do not eat animal products, check food labels to determine whether the foods you regularly consume actually contain added B12.
Do You Need a Vitamin B12 Supplement?
Not everyone needs a B12 supplement.
People who have a confirmed deficiency, have a medical condition affecting absorption, follow a strict vegan diet or have another recognised risk factor may need supplementation.
The amount and form of supplementation can vary depending on the cause and severity of deficiency.
Taking extremely high doses without a reason is not necessarily better. If you suspect that you may be deficient, speak with a healthcare professional about whether testing or supplementation is appropriate.
Can You Get Too Much Vitamin B12?
Vitamin B12 is generally considered to have a low potential for toxicity, and the body can eliminate excess amounts.
However, this does not mean that every supplement is necessary or appropriate for everyone.
If you are taking multiple supplements or medications, it is useful to tell your healthcare professional what you are taking.
How Can You Reduce Your Risk of B12 Deficiency?
The best approach depends on why you may be at risk. If you eat animal-source foods, regularly including fish, meat, eggs or dairy products can help provide B12.
If you follow a vegan diet, make sure you have a dependable source of B12 through fortified foods or an appropriate supplement.
If you take medications such as metformin for a long period or have a digestive condition that affects absorption, ask your healthcare professional whether your B12 status should be monitored.
Older adults and people with previous stomach or intestinal surgery may also benefit from discussing their individual risk with a healthcare professional.
When Should You See a Healthcare Professional?
Consider speaking with a healthcare professional if you have persistent tiredness, unexplained weakness, numbness, tingling, balance problems, memory changes or other symptoms that concern you.
You should also discuss B12 testing if you follow a strict vegan diet, have a condition affecting nutrient absorption, have had gastrointestinal surgery or take medications that may affect B12 absorption.
Early evaluation is particularly important when neurological symptoms are present because prolonged deficiency can cause nerve problems.
Final Thoughts
Vitamin B12 is a small nutrient with an important role in the body. It supports healthy red blood cells, normal nerve function and DNA production, but certain people are more likely to develop a deficiency.
Older adults, people following strict vegan diets, individuals with certain digestive conditions, people who have undergone gastrointestinal surgery and those taking certain medications may need particular attention to their B12 status.
A balanced diet can provide B12 for many people, while others may need fortified foods, supplements or medical treatment. If you have symptoms or risk factors, do not assume that B12 deficiency is the cause. A healthcare professional can help determine whether testing and treatment are appropriate.