From persistent fatigue to memory lapses and tingling feet, vitamin B12 deficiency can mimic the signs of ageing, and it is more common than many people realise.
Most people do not spend much time thinking about vitamins, let alone a specific vitamin like B12.
It is needed in very small amounts, yet it plays an essential role in keeping the body functioning properly. Vitamin B12 helps produce red blood cells, supports nerve health and is involved in DNA production. Without enough of it, the effects can extend far beyond simple tiredness.
While vitamin B12 deficiency can affect people of any age, it becomes increasingly common as we grow older. The challenge is that many of its symptoms can look remarkably similar to what people assume is “normal ageing”.
Why Does Vitamin B12 Matter?
Vitamin B12, also known as cobalamin, is a nutrient found naturally in animal-based foods such as meat, fish, eggs and dairy products.
The body uses it for several important functions, including:
- Producing healthy red blood cells
- Maintaining healthy nerves
- Supporting brain function
- Helping cells create and repair DNA
Because the body cannot produce vitamin B12 on its own, it must come from food or supplements.
Vitamin B12 Sources
Vitamin B12 is naturally found almost exclusively in animal-based foods. Most people can obtain enough vitamin B12 through a balanced diet, although needs and absorption may change with age.
Some of the richest dietary sources include:
- Liver and organ meats
- Shellfish such as clams, oysters and mussels
- Fish including salmon, tuna, sardines and mackerel
- Beef and poultry
- Eggs
- Milk, yoghurt and cheese
For vegetarians and vegans, obtaining enough vitamin B12 can be more challenging because plant foods generally do not contain significant amounts of the vitamin. Fortified foods such as some breakfast cereals, plant-based milks and nutritional yeast may help, while some people may require supplementation.
Importantly, eating more vitamin B12-rich foods may not fully correct a deficiency if the underlying problem is poor absorption. This is why older adults and people with certain medical conditions may still develop low vitamin B12 levels despite having an adequate diet.
Why Are Older Adults More Likely to Develop Vitamin B12 Deficiency?
One of the biggest reasons is that vitamin B12 becomes harder to absorb with age.
To absorb vitamin B12 from food, the stomach needs to produce sufficient acid and a protein known as intrinsic factor. Both help release and transport the vitamin so it can be absorbed in the intestines.
As people get older, this process may become less efficient.
Some older adults produce less stomach acid. Others develop conditions such as autoimmune gastritis, where the immune system damages stomach cells involved in vitamin B12 absorption.
Certain medications can also interfere with absorption. These include some medicines used to treat acid reflux and diabetes.
People who have undergone weight-loss surgery may face similar challenges.
What Are the Symptoms of Low Vitamin B12?
Vitamin B12 deficiency often develops gradually.
Symptoms can be subtle at first and may worsen over time if left untreated.
Common symptoms include:
- Persistent fatigue
- Weakness
- Shortness of breath
- Numbness or tingling in the hands and feet
- Poor balance
- Memory problems
- Difficulty concentrating
- Brain fog
Because these symptoms are common in many health conditions, they are sometimes dismissed as stress, ageing or simply “slowing down”.
However, persistent symptoms should be assessed by a healthcare professional rather than automatically attributed to age.
Can Vitamin B12 Deficiency Affect the Brain?
Vitamin B12 plays an important role in maintaining healthy nerve cells.
When levels become too low, neurological symptoms can develop. This is why some people experience tingling sensations, balance difficulties or cognitive changes.
Researchers have also become increasingly interested in the relationship between vitamin B12 and brain health during ageing.
Although vitamin B12 deficiency is not the only cause of memory problems, identifying and treating a deficiency early may help prevent further complications.
What is the Connection Between Vitamin B12 and Energy?
Doctors have traditionally linked fatigue from vitamin B12 deficiency to anaemia.
Without enough vitamin B12, the body cannot produce healthy red blood cells efficiently. This reduces the blood’s ability to transport oxygen around the body, leading to tiredness and weakness.
However, newer research suggests there may be more to the story.
Recent studies have examined vitamin B12’s role inside mitochondria – the structures often described as the cell’s “power plants”.
Researchers found that low vitamin B12 levels may affect how mitochondria function, potentially reducing the cell’s ability to generate energy efficiently.
Animal studies have also suggested that vitamin B12 supplementation may improve certain markers of mitochondrial health.
While these findings are intriguing, experts caution against viewing vitamin B12 as a miracle energy booster.
Should Everyone Take Vitamin B12 Supplements?
Not necessarily.
Vitamin B12 supplements can be highly effective for people who have a deficiency or are at increased risk of developing one.
However, there is little evidence that taking extra vitamin B12 provides additional energy or health benefits for people whose levels are already normal.
This is also true for vitamin B12 injections, which are increasingly marketed by wellness clinics and medical spas as solutions for fatigue, weight loss or enhanced performance.
For individuals with confirmed vitamin B12 deficiency, injections remain an important medical treatment, particularly when the body cannot absorb vitamin B12 properly. For everyone else, the first step should be understanding the cause of their symptoms rather than assuming vitamin B12 is the answer.
Who Should Consider Getting Their Vitamin B12 Levels Checked?
Certain groups may be at higher risk of deficiency, including:
- Adults aged 60 and above
- Vegans and vegetarians
- People taking long-term acid reflux medications
- People taking certain diabetes medications such as metformin
- Individuals with digestive disorders that affect nutrient absorption
- People who have undergone weight-loss surgery
If you regularly experience fatigue, numbness, balance problems or unexplained cognitive changes, it may be worth discussing vitamin B12 testing with your doctor.
The Bottom Line
Vitamin B12 may be needed only in tiny amounts, but its impact on health can be significant.
For older adults, symptoms such as fatigue, memory problems and poor balance are not always an inevitable part of ageing. In some cases, they may signal an underlying vitamin B12 deficiency that can be identified and treated.
As researchers continue exploring vitamin B12’s role in energy production, muscle health and healthy ageing, one message remains clear: when it comes to vitamin B12, small deficiencies can have surprisingly large consequences.
