Eight key B vitamins: what they do and which foods provide them

Our bodies rely on a wide mix of vitamins and minerals to keep blood cells, hormones, and the immune, nervous, and cardiovascular systems functioning well. Yet with the supplement market growing quickly, it can be easy to forget what these nutrients actually do and which everyday foods contain them.

One group that is often overlooked is the B vitamins. These essential nutrients support several vital processes in the body. How much each person needs depends on age, diet, general health, and life stage, but specialist dietitian Nichola Ludlam-Raine says they collectively help the body release energy from food, produce and maintain red blood cells, support the nervous system, and aid DNA production and cell growth.

A balanced diet can supply most B vitamins, but like many nutrients, a deficiency may only become obvious once the body starts sending warning signs. Tina Hancocks, a registered nutritional therapist and ambassador to Wiley's Finest fish oils, says that if you feel exhausted despite sleeping well, mentally foggy, low, anxious, or inflamed, a shortage of B vitamins is one possible cause.

There are eight B vitamins in total, though many people could probably name only one or two. Folate and B12 are the best known, but the rest are less familiar. Dietitians and nutrition experts explain what each one does and why they matter for both immediate and longer-term health.

What are the eight B vitamins?

B1 or thiamin

Vitamin B1 helps the body break down food and turn it into energy, and it also plays an important role in nervous system health. Most people can usually get enough from food alone because it is found in peas, bananas, nuts, wholegrain cereals, and fortified cereals.

B2 or riboflavin

Vitamin B2 is essential for keeping the eyes, skin, and nervous system healthy. Common sources include milk, eggs, fortified breakfast cereals, plain yogurt, and mushrooms. Because UV light can damage riboflavin, foods that contain it should be stored away from direct sunlight.

B3 or niacin

Niacin also helps the body release energy and supports healthy skin and nervous system function. Meat, fish, eggs, and wheat flour contain two forms of vitamin B3: nicotinic acid and nicotinamide. Supplements are usually unnecessary, and the NHS warns that too much nicotinic acid over time can cause skin flushing and liver damage.

B5 or pantothenic acid

Pantothenic acid is present in most vegetables and helps the body release energy from food. It is also added to some breakfast cereals, while other sources include chicken, beef, eggs, mushrooms, and avocado.

B6 or pyridoxine

This important vitamin helps the body use and store energy from the protein and carbohydrates we eat. It also supports haemoglobin production, which red blood cells need to carry oxygen around the body. Good sources include soya beans, poultry, pork, oats, bananas, milk, and peanuts.

Most people should be able to get enough B6 through food, but if you have been advised to take a supplement, do not exceed 10mg a day. Too much can lead to peripheral neuropathy, a condition that causes loss of feeling in the arms and legs.

B7 or biotin

Biotin is found in many of the foods already mentioned, but the body only needs a small amount to help make fatty acids and keratin for healthy hair and nails. Gut bacteria can also produce it, so supplements are generally not recommended. If you do take one, it should not exceed 0.9mg a day. Other food sources include eggs, salmon, meat, nuts, legumes, and sweet potatoes.

B9 folate/folic acid

Folate is one of the best-known B vitamins. Women trying to conceive or in their first trimester are advised to take a daily supplement. It helps the body make red blood cells and lowers the risk of neural tube defects, which can lead to conditions such as spina bifida in unborn babies. A shortage can also cause folate deficiency anaemia. Adults need around 200μg a day, while pregnancy calls for 400μg a day until 12 weeks.

Folate is also found in broccoli, cabbage, kale, spinach, peas, chickpeas, kidney beans, and fortified cereals.

B12 or cobalamin

Vitamin B12 has several essential roles. It helps the body make red blood cells, use folate, and release energy from food. It is found in meat, fish, eggs, milk, and cheese, but Ludlam-Raine says vegans and vegetarians should choose reliable fortified foods such as Alpro soya milk or take a B12 supplement.

A deficiency can cause B12 deficiency anaemia, which may lead to extreme tiredness, mouth ulcers, weak muscles, and vision problems. A blood test can show whether treatment is needed, and that may involve either B12 injections or tablets.

Think food first

As the list shows, most B vitamins can be obtained through diet. But Priya Tew, a specialist dietitian at Dietitian UK, notes that they need replenishing every day because they are water-soluble and cannot be stored by the body.

Hancocks says that while a balanced diet rich in whole foods and leafy greens covers most B vitamin needs, modern life can make shortfalls more likely. Ultra-processed food, ongoing stress, alcohol, some medications, gut imbalances, and plant-based diets can all create gaps.

The two B vitamins most likely to need attention are folate and B12, which are also the supplements people most often take. B12 is especially important for vegans because it is not naturally present in plant-based foods. Tew adds that older adults may also need a B12 supplement because stomach acid production often declines with age, which can reduce absorption from food. Even so, too much of any B vitamin can be a problem, so it is important to speak to a doctor before starting a new supplement. Tew also stresses the importance of eating regularly and enough, since skipping meals or restricting food intake will not help.

On perimenopause, the experts say there is no evidence that women need more B vitamins. Ludlam-Raine says they are needed for normal body function and to correct deficiencies, but that is different from proof that extra B vitamins ease perimenopause symptoms. She advises caution with high-dose products marketed for hormones or energy, especially those containing high levels of vitamin B6.

If you have questions or concerns about your diet or health, speak to your GP for the right advice.