What Does Vitamin B12 Do for You?

What Vitamin B12 Does in Your Body

Vitamin B12 is a nutrient your body needs but cannot make on its own. You get it from food, or sometimes from supplements or injections. It does several jobs that keep you well.

B12 helps your body make red blood cells. These cells carry oxygen around your body. Without enough B12, you can develop anaemia, which makes you tired and short of breath.

It also protects your nerves. B12 keeps the coating around nerve fibres intact. This coating, called myelin, lets your nerves send signals properly. When B12 runs low, your nerves can become damaged, causing tingling in your hands and feet, or problems with balance.

B12 helps your body use energy from food. It breaks down proteins and fats so your cells can use them. Low B12 can leave you feeling exhausted, even when you have slept well.

Your brain needs B12 too. It helps make neurotransmitters, the chemicals your brain uses to think and remember. Some research suggests low B12 may affect mood and concentration.

Who Needs to Pay Attention to B12

Some people are at higher risk of B12 deficiency. If you are over 50, your stomach may not absorb B12 from food as well as it once did. Vegans and vegetarians need to be careful because B12 is mainly found in animal products like meat, fish, eggs, and dairy.

Certain medicines can lower B12 levels. Metformin, used for diabetes, and some medicines for acid reflux can interfere with absorption. If you take these long-term, your GP or pharmacist may suggest checking your B12 level.

Conditions that affect your gut, such as coeliac disease or Crohn's disease, can stop you absorbing B12 properly. Pernicious anaemia is an autoimmune condition where your body cannot absorb B12 at all, even from food.

People who have had weight loss surgery may also struggle to absorb B12 and may need regular injections.

How B12 Works in Your Body

Absorption and Storage

When you eat food containing B12, your stomach produces a substance called intrinsic factor that helps you absorb it. The B12 then travels to your small intestine and enters your bloodstream. Your body stores B12 in your liver, which can hold enough for two to three years.

Energy and Red Blood Cells

B12 is essential for making DNA and red blood cells. Red blood cells live for about four months. Your bone marrow makes new ones constantly, and B12 is needed for this process. Without it, your body makes fewer red blood cells, and the ones it does make may be larger than normal and work less well.

Nerve Protection

B12 maintains myelin, the protective sheath around nerves. This is why B12 deficiency can cause nerve damage (neuropathy) if it goes untreated for a long time. Symptoms include pins and needles, numbness, or weakness in your legs.

Metabolism

B12 helps convert carbohydrates, proteins, and fats into energy your cells can use. It also helps regulate homocysteine, an amino acid. High homocysteine is linked to heart and bone health problems, so keeping B12 levels normal is protective.

Signs You Might Be Low in B12

Fatigue is the most common symptom. You may feel tired even after a full night's sleep, and everyday tasks feel harder.

Shortness of breath, especially on exertion, can signal anaemia from low B12.

Pins and needles, numbness, or a tingling sensation in your hands and feet suggests nerve involvement.

Mouth ulcers or a sore, swollen tongue sometimes occur.

Some people notice they are more forgetful, find it hard to concentrate, or feel low in mood.

Pale or slightly yellowed skin can be a sign of anaemia.

If you have any of these symptoms, speak to your GP or pharmacist. They can arrange a blood test to check your B12 level. Do not wait for symptoms to get worse, because nerve damage from B12 deficiency can become permanent if left untreated.

Common Questions About Vitamin B12

Can you get too much B12?

B12 is water-soluble, which means your body excretes excess amounts in urine. Toxicity from too much B12 is very rare. Injections and supplements are considered safe at high doses.

How long does it take to feel better after a B12 injection?

Some people feel more energetic within days. Others take weeks or months to notice improvement. Nerve damage takes longer to heal than anaemia. If you have had symptoms for a long time, recovery can take several months.

Do I need injections or can I take tablets?

It depends on why your B12 is low. If your stomach absorbs B12 normally, tablets or food sources are fine. If you have pernicious anaemia or cannot absorb B12 from food, injections work better because they bypass the stomach and go straight into the bloodstream.

How often do I need B12 injections?

This varies. Some people need one every eight to twelve weeks. Others need them more or less often. Your doctor or pharmacist will advise based on your condition and how you respond.

Can vegans get enough B12 without supplements?

Most vegans need either fortified foods (like plant-based milks and cereals) or a supplement. B12 from plant sources is not reliable unless the food has been fortified. Talk to a pharmacist about what suits you.

Is B12 deficiency common?

Yes. It affects about one in 2,000 people in the UK. It is more common in older people and those with certain conditions. A simple blood test can tell you if you are deficient.

Get Your B12 Levels Checked

If you think you might be low in B12, or if you have symptoms like fatigue, tingling, or difficulty concentrating, book an appointment with Fulham Palace Pharmacy in Fulham. The team can discuss your symptoms, arrange a blood test if needed, and talk through whether a B12 injection might help you. Fulham Palace Pharmacy offers same-day and evening appointments, so you can fit your health around your schedule. Get in touch today to book your consultation.

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