Vitamin B

Overview

Vitamin B refers to a group of eight water-soluble vitamins that help your body turn food into energy, keep your brain and nerves healthy, and help make red blood cells. The group includes vitamins B1, B2, B3, B5, B6, B7, B9 and B12. They are sometimes called B-complex vitamins.

Vitamin B deficiency is uncommon in people who eat a varied diet, but it can happen, especially in older adults, pregnant women, vegans and people with digestive problems.

It can affect people of any age, but certain groups are more at risk, including older adults, people who follow a vegan or vegetarian diet, people with conditions that affect how the body absorbs nutrients, and people who drink alcohol heavily.

Symptoms

Common symptoms

• Feeling very tired or weak
• Pale skin
• Shortness of breath on mild exertion
• Tingling or numbness in the hands and feet
• Mouth ulcers or cracked lips
• Poor concentration or brain fog

Symptoms in children

• Being unusually irritable or fussy
• Poor growth or weight gain
• Delays in reaching developmental milestones
• Tiredness or lack of energy

Symptoms in older adults

• Confusion or memory problems
• Numbness or balance problems
• Severe tiredness that affects daily activities
• Changes in appetite or weight loss

Causes

Main causes

• A diet lacking in B vitamins — for example, not eating enough whole grains, vegetables, eggs or dairy
• The body not absorbing vitamins properly, as can happen in some digestive disorders or after certain weight-loss surgeries
• Heavy or long-term alcohol use
• Pregnancy, because the body needs more B vitamins, especially folate
• Certain medicines that interfere with how the body uses B vitamins

Risk factors

• Vegan or vegetarian diet without reliable sources of vitamin B12
• Being over 65, as the stomach makes less acid needed to absorb B12
• Having celiac disease, Crohn's disease or other gut conditions
• Long-term use of certain acid-suppressing medications
• Regularly drinking more than the recommended alcohol limits

When to see a doctor

See a doctor urgently if:

• Sudden severe weakness, numbness or confusion
• Difficulty breathing or chest pain
• Fainting or seizures

Book a routine appointment if:

• Persistent tiredness that is not explained by your sleep or activity
• Frequent mouth ulcers, cracked lips or skin rashes
• Numbness or tingling that doesn't go away
• Unexplained weight loss or loss of appetite

Diagnosis

A doctor can check for vitamin B deficiency by asking about your symptoms, medical history and diet, and by ordering a simple blood test. The blood test measures levels of specific B vitamins, most commonly vitamin B12 and folate.

Tests that may be done

• Full blood count to look for anemia
• Serum B12 test to check vitamin B12 levels
• Folate test to check vitamin B9 levels
• Sometimes additional tests for absorption, depending on your results

What to expect at your appointment

The blood test is quick and is usually done at your GP surgery or local clinic. Results typically come back within a few days. If the results show a deficiency, your doctor will explain what it means and work with you on treatment.

Treatment

Treatment depends on the cause and the type of B vitamin that is low. The goal is to restore normal levels and address any underlying problems. For most people, this means improving the diet and, if needed, taking vitamin B supplements. In some cases, injections or higher-dose supplements are used, and that would be arranged by your doctor or practice nurse.

Self-care at home

• Eat a varied diet that includes whole grains, legumes, eggs, dairy, lean meat, fish and leafy green vegetables.
• If you are vegetarian or vegan, talk to a dietitian about reliable sources of B12, such as fortified plant-based milks and breakfast cereals.
• Limit alcohol and get support if you are drinking more than is safe.
• Take supplements only as recommended by a healthcare professional — more is not better.

Medical treatments

Your doctor may recommend a vitamin B supplement. This could be a B-complex product that contains several B vitamins, or a single vitamin such as vitamin B12. If you have low vitamin B12, the doctor may arrange for you to have injections until your levels are back to normal. Always take supplements exactly as directed. Do not start a supplement without talking to your doctor, because high doses of some B vitamins can be harmful.

When is surgery considered?

Surgery is not a treatment for vitamin B deficiency. In rare cases, surgery may be needed to treat an underlying condition causing the deficiency, such as a bowel problem, but that is decided on an individual basis by your specialist.

Living with this condition

Managing a vitamin B deficiency usually becomes easier with simple routines. Take any supplements at the same time each day, keep a food diary to track how much you eat from B-vitamin-rich foods, and book follow-up checks when your doctor asks you to.

Lifestyle tips

• Plan regular, balanced meals so you do not skip meals and end up relying on processed snacks.
• If you have alcohol dependence, seek help to reduce your drinking — your GP can support you.
• Get enough sleep and manage stress, as both affect your energy levels.

Diet and exercise

Regular physical activity can help boost your energy and mood, but it should not replace good nutrition. Eat a variety of foods: wholemeal bread, rice and oats; beans, lentils and chickpeas; eggs, milk and yoghurt; leafy green vegetables; and, if you eat meat, chicken, fish and lean red meat. If you have trouble chewing or swallowing, speak to a dietitian about softer ways to get these nutrients.

Mental health and emotional wellbeing

A vitamin B deficiency, especially low B12 or folate, can make you feel low, anxious or irritable. This can be distressing. Treating the deficiency often improves how you feel, but if you are struggling with your mood, please talk to your doctor. Support from family, friends, or a counsellor can also help.

Prevention

Almost always. In most cases, vitamin B deficiency can be prevented by eating a healthy, varied diet and, for people at high risk, by taking recommended supplements during pregnancy or under medical advice. If you have a condition that affects absorption, regular check-ups and prescribed supplements are the best way to maintain healthy levels.

Vaccines

There is no vaccine against vitamin B deficiency. The best protection is a nutrient-rich diet and, when needed, supplements that your doctor has recommended.

Screening programmes

In the UK, pregnant women are offered folate supplements during early pregnancy to prevent neural tube defects. People at higher risk, for example those with pernicious anemia or absorption problems, may have regular blood tests to monitor B12 levels. Your doctor can tell you whether you need screening.

Complications

If left untreated

• Anaemia, which makes you feel weak, tired and short of breath
• Nerve damage, causing persistent tingling, numbness or problems walking
• Cognitive problems that may look like dementia, especially in older adults
• Folate deficiency in pregnancy can increase the risk of neural tube defects in the baby

Long-term outlook

The outlook is very good if a vitamin B deficiency is caught early. With the right treatment — whether through food, supplements or injections — most people feel much better within weeks and can return to their normal activities. Serious damage is rare if you act early, so do not put off seeing your doctor if you are worried.

Find support

Local organisations

• NHS Choices – Vitamins and minerals ↗ · United Kingdom

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