Tired, Tingling or Wondering If Your Vitamin B12 Is Low?
Vitamin B12 is essential for healthy red blood cell formation, normal nerve function and DNA production. But getting enough B12 isn’t only about how much you eat — your ability to absorb it matters too.
Low vitamin B12 can occur with inadequate dietary intake, particularly in vegan diets, but it can also occur when B12 isn’t being absorbed effectively.
This guide explains vitamin B12 deficiency symptoms, B12-rich foods, vegetarian and vegan sources, absorption, blood testing and when supplementation may need to be considered.
What Is Vitamin B12 Deficiency?
Vitamin B12 deficiency occurs when the body does not have enough vitamin B12 to meet its needs. This may happen because dietary intake is inadequate or because B12 is not being absorbed properly.
Because vitamin B12 is important for blood and neurological function, deficiency can cause symptoms ranging from fatigue and weakness to numbness, tingling and other neurological changes.
What Does Vitamin B12 Do?
Vitamin B12, also known as cobalamin, is required for several important processes within the body, including:
- Normal red blood cell formation
- Normal nervous system function
- DNA synthesis
- Normal cell function and repair
This is why significant B12 deficiency can affect both the blood and nervous system.
What Are the Symptoms of Vitamin B12 Deficiency?
Vitamin B12 deficiency can develop gradually, and symptoms can vary between individuals.
Possible symptoms can include:
- Fatigue or unusual tiredness
- Weakness
- Light-headedness
- Numbness or tingling in the hands or feet
- Balance difficulties
- A sore or inflamed tongue
- Memory or concentration changes
- Mood or cognitive changes
These symptoms are not specific to B12 deficiency. Fatigue, tingling, dizziness and cognitive changes have many possible causes, so appropriate medical assessment and testing are important.
Can Low Vitamin B12 Cause Fatigue?
Yes, fatigue can occur with vitamin B12 deficiency, particularly when deficiency contributes to abnormal red blood cell production or anaemia.
However, feeling tired does not automatically mean your B12 is low. Iron deficiency, sleep problems, thyroid conditions, inadequate energy intake, stress and many other factors can also contribute to fatigue.
This is why we prefer investigating the broader nutritional and health picture rather than assuming one nutrient explains every symptom.
Learn more about iron deficiency and nutrition.
What Foods Are High in Vitamin B12?
Vitamin B12 occurs naturally predominantly in animal-derived foods.
Good Dietary Sources of Vitamin B12
- Fish and seafood
- Meat
- Poultry
- Eggs
- Milk
- Yoghurt
- Cheese
Some plant-based foods, including certain breakfast cereals, nutritional yeasts and plant milks, may contain B12 when they have been fortified.
Always check the nutrition information panel because B12 content varies substantially between fortified products.
Can Vegetarians Get Enough Vitamin B12?
Vegetarians who consume eggs and dairy foods can obtain vitamin B12 from these foods, although actual intake depends on how frequently and how much they consume.
If your diet contains only small amounts of animal-derived foods, it is worth considering whether you have a reliable regular source of B12.
Can Vegans Get Vitamin B12 From Food?
A vegan diet requires particular attention to vitamin B12. Reliable natural plant sources are very limited, so fortified foods and/or an appropriate B12 supplement are commonly required to provide a dependable source.
People following vegan diets should not assume that vegetables, fermented foods or unfortified nutritional yeast will reliably provide sufficient B12.
A personalised dietary review can help determine whether your current diet provides an adequate and dependable B12 intake.
How Much Vitamin B12 Do You Need Per Day?
The Australian Recommended Dietary Intake for vitamin B12 is approximately 2.4 micrograms per day for adults.
The RDI increases to approximately 2.6 micrograms per day during pregnancy and 2.8 micrograms per day while breastfeeding.
These are dietary reference values and should not be confused with therapeutic supplement doses used when treating an identified deficiency.
Why Might Vitamin B12 Be Low Even If You Eat Meat?
Eating B12-containing foods does not necessarily guarantee that all of the vitamin B12 will be absorbed.
Vitamin B12 absorption is a multi-step process involving the stomach, digestive enzymes, intrinsic factor and the small intestine.
Low B12 can therefore sometimes occur even when dietary intake appears adequate.
What Can Affect Vitamin B12 Absorption?
Vitamin B12 from food must first be released from food proteins before it can be absorbed.
Factors that may contribute to poor B12 status include:
- Conditions affecting the stomach or small intestine
- Pernicious anaemia and impaired intrinsic factor
- Some gastrointestinal surgery
- Increasing age
- Certain medications that affect B12 absorption
- Long-term highly restrictive dietary patterns
If B12 remains low despite apparently adequate dietary intake, investigating why it is low is important.
Can Stomach Acid Affect Vitamin B12 Absorption?
Stomach acid helps release food-bound vitamin B12 during digestion. This is one reason conditions or medications that substantially alter stomach function can influence B12 absorption in some people.
However, low B12 should not automatically be assumed to mean you have “low stomach acid”. There are multiple possible causes that require appropriate assessment.
How Is Vitamin B12 Deficiency Tested?
A blood test can measure vitamin B12 levels and is often considered alongside other blood results and your symptoms.
Your doctor may also assess folate, full blood count and other markers depending on your circumstances.
If results are unclear or deficiency is suspected despite borderline B12 levels, additional investigations may sometimes be appropriate.
Learn more about functional and nutritional testing at Morkare.
Vitamin B12 and Folate: What’s the Connection?
Vitamin B12 and folate are both involved in important cellular processes and normal blood formation.
Because these nutrients interact metabolically, taking high-dose folic acid without considering B12 status can complicate the recognition of B12 deficiency.
This is another reason supplementation should be based on your individual nutritional picture rather than simply taking more of every B vitamin.
Do You Need a Vitamin B12 Supplement?
Not everyone needs a B12 supplement, but supplementation may be particularly relevant for people with an identified deficiency, inadequate dietary intake or increased risk of poor B12 status.
This can include some:
- Vegans
- Vegetarians with low B12 intake
- Older adults
- People with conditions affecting B12 absorption
- People taking certain medications
- People who have undergone particular gastrointestinal procedures
The appropriate form and dose depends on why B12 is low and the severity of deficiency.
Personalised Nutrition Support in Brisbane
If your B12 is low, the most useful question isn’t simply “Which B12 supplement should I buy?” It is also: “Why is my B12 low?”
At Morkare Natural Clinic, we can review your dietary intake, food restrictions, symptoms, existing blood results, supplements and relevant health history as part of a broader nutritional assessment.
We also consider related nutrients such as iron, protein, vitamin D, calcium, magnesium and zinc rather than viewing B12 in isolation.
Learn more about our Clinical Nutritionist Brisbane service.
Appointments are available at our Holland Park West clinic in Brisbane and by telehealth Australia-wide.
Frequently Asked Questions About Vitamin B12
What are the first signs of B12 deficiency?
Vitamin B12 deficiency can cause fatigue, weakness and neurological symptoms such as numbness or tingling. These symptoms are not unique to B12 deficiency, so blood testing and appropriate assessment are important.
What foods are highest in B12?
Vitamin B12 is found predominantly in animal-derived foods including meat, fish, seafood, eggs and dairy foods. Fortified plant foods can also provide B12.
How much B12 do I need per day?
The Australian RDI for adults is approximately 2.4 micrograms per day, increasing during pregnancy and breastfeeding.
Can vegetarians become B12 deficient?
Yes. Vegetarians can obtain B12 from eggs and dairy foods, but people consuming only small quantities may still have inadequate intake.
Do vegans need vitamin B12?
Vegans need a reliable source of vitamin B12 because dependable natural plant sources are limited. Fortified foods and/or appropriate supplementation are commonly used.
Can you have B12 deficiency even if you eat meat?
Yes. B12 deficiency can result from impaired absorption as well as inadequate intake, so eating B12-containing foods does not rule out deficiency.
Can low B12 cause tingling?
Vitamin B12 deficiency can cause neurological symptoms including numbness and tingling. Persistent or unexplained neurological symptoms should be medically assessed.
How do you test vitamin B12?
Vitamin B12 can be measured with a blood test. Your doctor may consider the result alongside symptoms, a full blood count, folate and other investigations.
Why isn’t my B12 increasing?
Persistently low B12 can have several explanations, including inadequate intake, poor absorption, medication effects or underlying gastrointestinal factors. The cause should be investigated rather than repeatedly increasing supplements without assessment.
Important Information
This information is for general education and does not replace medical or individual nutritional advice. Vitamin B12 deficiency can cause neurological complications. If you have persistent numbness, tingling, balance changes, significant weakness or other concerning symptoms, seek appropriate medical assessment.