Vitamin B6: Benefits – Symptoms of Vitamin B6 Deficiency

Vitamin B6, also known as pyridoxine, is a water-soluble vitamin that plays an important role in keeping the body functioning at its best. It's involved in energy metabolism, contributes to the normal working of the nervous system and supports immune health.

Since the body can't produce it on its own, you need to obtain enough vitamin B through a balanced diet or with the help of supplements.

What is vitamin B6

Vitamin B is one of the 8 compounds that make up the vitamin B complex – alongside B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B7 (biotin), B9 (folic acid) and B12 (cobalamin). It's a water-soluble vitamin, meaning it dissolves in water.

Vitamin B6 itself occurs in 3 main chemical forms:

• Pyridoxine (PN): found in fruit, vegetables and cereals, and well tolerated by the body; this is also the form most commonly found in vitamin B6 supplements.
• Pyridoxal (PL): more precisely pyridoxal phosphate – the form most commonly found in foods of animal origin.
• Pyridoxamine (PM): another form of vitamin B6 frequently found in foods of animal origin. It has been studied for its effects in treating diabetic nephropathy and, according to the FDA (the US Food and Drug Administration), is currently classified as a pharmaceutical medicine rather than a dietary supplement.

Once vitamin B6 enters the body in one of these forms, it is absorbed in the small intestine and travels to the liver, where it is converted into pyridoxal 5'-phosphate (PLP or P-5-P) – its biologically active form, so that it can be used by the body.

Once synthesised, pyridoxal 5'-phosphate is involved in over 100 enzymatic reactions, chiefly relating to energy metabolism and nervous system function. It acts as a coenzyme in the metabolism of amino acids, carbohydrates and fats, and is essential for the synthesis of neurotransmitters as well as for normal brain function.

Vitamin B6 – role and functions in the body

Vitamin B6 is essential to numerous processes and functions within the body, but it supports the organism in two main ways. Firstly, it helps metabolise proteins, carbohydrates and fats to convert food into energy; secondly, it supports the body in producing haemoglobin and neurotransmitters.

Vitamin B6 – energy metabolism

Pyridoxine works at cellular level, helping to convert the proteins, fats and carbohydrates obtained through diet into energy. Its job is to support the normal running of the processes involving these nutrients, thereby promoting the health of the brain, nerves, skin and the body as a whole.

Vitamin B6 is also involved in the synthesis of amino acids, in the conversion of tryptophan into niacin, and helps maintain glycogen stores in the liver and muscles.

Vitamin B6 – nervous system and brain health

Another important role of vitamin B6 is its involvement in the synthesis of neurotransmitters, which play a central part in sleep quality and memory, as well as in processes such as mood regulation, stress relief and maintaining emotional balance:

• Serotonin, responsible for regulating good mood and for combating anxiety and depression.
• Dopamine, involved in regulating emotions and in the brain's reward system.
• GABA (gamma-aminobutyric acid), an inhibitory neurotransmitter that helps calm the nervous system.
• Noradrenaline, a hormone that helps regulate stress levels in the body.

A vitamin B deficiency can lead to imbalances in these neurotransmitters and bring on symptoms such as irritability, confusion, anxiety or even depression.

Vitamin B6 – immune function

Pyridoxine supports the production of antibodies and the activity of lymphocytes – the white blood cells responsible for the body's immune defences. It is directly involved in processes that support the body's immune response during periods of stress or illness, enabling it to fight infection and inflammation effectively.

Vitamin B6 – haemoglobin production and blood health

Vitamin B6 is essential to processes such as the synthesis of haemoglobin, which is responsible for transporting oxygen from the lungs to the tissues, as well as for the normal formation of red blood cells.

When vitamin B6 levels in the body are optimal, the vitamin supports efficient oxygen supply throughout the body and helps prevent anaemia and its associated symptoms, such as dizziness, pallor, weakness and marked fatigue.

Vitamin B6 – dietary sources

The body doesn't produce vitamin B6 itself, so you need to make sure you're getting enough through your diet. You can do this both through foods rich in vitamin B6 and through supplements, if your doctor recommends them.

When it comes to food, you can choose from a wide variety of plant-based vitamin B6 sources, animal sources and fortified foods that help you meet your daily requirement more easily. Generally speaking, animal sources have better bioavailability than plant ones, as they contain a form of vitamin B that the body absorbs more readily.

The main natural sources of vitamin B6 include:

• Meat and fish: chicken, turkey, pork, tuna, salmon, liver.
• Vegetables and pulses: chickpeas, potatoes, lentils, spinach.
• Fruit: bananas, avocado, honeydew melon.
• Seeds and nuts: sunflower seeds, hazelnuts, almonds.
• Wholegrain cereals and wheat products.

Worth knowing: excessive cooking, boiling or lengthy processing of these foods can reduce their vitamin B6 content by up to 40%. It's therefore best to cook them for as short a time as possible.

Vitamin B6 – recommended daily dose

Daily vitamin B6 requirements vary from person to person and depend on age, sex and – for women – life stages such as pregnancy or breastfeeding. The recommended daily doses fall within the following ranges:

• Men: 1.3–1.7 mg/day.
• Women: 1.2–1.5 mg/day
• Women during pregnancy and breastfeeding: 1.9–2.0 mg/day.

The maximum dose of vitamin B6 an adult body can tolerate is 100 mg/day. Exceeding this over the long term can cause side effects, particularly of a neurological nature.

To avoid the risks associated with overdosing, you should only supplement with B6 on medical advice – usually when tests show a deficiency or when your requirements are higher due to certain conditions.

Vitamin B6 – scientifically proven benefits

Because of its involvement in numerous bodily processes, vitamin B6 has been studied extensively over the years, and its benefits are backed by a substantial body of scientific evidence. Its active form, pyridoxal 5'-phosphate, takes part in dozens of enzymatic reactions that influence metabolism, nervous system function, hormonal balance and cardiovascular health.

Vitamin B6 – supporting energy metabolism

Vitamin B6 helps break down macronutrients and convert them into energy the body can use. Through its role in amino acid metabolism and in maintaining glycogen stores, pyridoxine supports energy levels and optimal bodily function, reducing fatigue and promoting day-to-day vitality.

Vitamin B6 – reducing the risk of anaemia

For the body to function normally, cells need oxygen. If they aren't supplied with enough of it, dizziness, weakness and even anaemia can result.

Pyridoxine plays a crucial role in the formation of red blood cells and in the synthesis of haemoglobin, the protein that carries oxygen around the body. By supporting these processes, vitamin B6 helps ensure cells are efficiently supplied with oxygen, thereby lowering the risk of anaemia.

Vitamin B6 – brain health and emotional balance

Vitamin B6 is directly involved in the synthesis and regulation of serotonin and other neurotransmitters essential to emotional balance. Put simply, when the body gets enough vitamin B6, it can balance serotonin, dopamine and GABA levels to maintain wellbeing and ease symptoms of anxiety, depression and insomnia.

Pyridoxine also contributes to the body's melatonin production, helping to regulate sleep and the body clock. Studies have further shown that optimal vitamin B6 levels support brain health and may help prevent Alzheimer's disease.

Vitamin B6 – premenstrual syndrome and pregnancy

Again because of its involvement in producing mood-regulating neurotransmitters, vitamin B6 is considered helpful in managing the symptoms of premenstrual syndrome. Experts note that it can help relieve irritability, fatigue, fluid retention, menstrual cramps and the anxiety and low mood typical of the premenstrual phase.

In pregnancy, vitamin B6 has been recommended for decades to ease nausea and vomiting in the first trimester. Exactly how it relieves the feeling of nausea isn't fully understood, but it's well established that adequate vitamin B6 intake is crucial to a healthy pregnancy, and that supplementation is safe provided the doses recommended by your doctor are respected.

Vitamin B6 – the link with menstruation and hormonal balance

Vitamin B6 influences women's hormonal health by helping to regulate the balance between oestrogen and progesterone levels. It's involved in metabolising oestrogen and supports the elimination of excess amounts, which are often linked to bloating, fluid retention and breast tenderness.

During menstruation, thanks to its contribution to serotonin production, pyridoxine also helps ease period pain, sudden mood swings and irritability. Studies show that women with adequate vitamin B6 intake experience milder premenstrual symptoms.

Vitamin B6 is also often recommended as a natural supplement, particularly in combination with calcium or magnesium, to reduce tension, irritability and anxiety during the luteal phase of the menstrual cycle.

For all its benefits, an excess of vitamin B6 can have harmful effects. Always follow your doctor's instructions so as not to exceed the recommended daily dose. There are other ways to lift your mood and feel better during your period too: a balanced diet, gentle physical exercise and using period products made from 100% organic cotton free from fragrances or toxic substances.

Vitamin B6 – cardiovascular function

Another benefit of vitamin B6 is its contribution to lowering homocysteine levels in the blood. Homocysteine is an amino acid whose raised concentration is a significant risk factor for cardiovascular disease – and pyridoxine can bring elevated levels down. It may also help prevent the blockage of the heart's arteries, thereby supporting circulation and the health of the heart and blood vessels.

Vitamin B6 – further benefits

Numerous studies have linked vitamin B6 to many other benefits over the years, including antioxidant effects, the ability to tackle inflammation in the body, improve cognitive function in older people and support the health of the skin, eyes and peripheral nervous system.

Vitamin B6 – deficiency and symptoms

Statistics show that vitamin B6 deficiency is relatively uncommon in most industrialised countries, as people naturally obtain enough through a balanced diet.

A deficiency arises when intake is inadequate, absorption is impaired, or the body's requirements increase – as happens with certain conditions or life stages. A vitamin B6 deficiency affects several of the body's systems.

Vitamin B6 deficiency – causes

An unbalanced diet, low in protein and wholegrains, is one of the most common causes of vitamin B6 deficiency.

Chronic, long-term alcohol consumption can also reduce the absorption and metabolism of vitamin B6, leading to a deficiency.

Another common cause of pyridoxine deficiency is conditions such as diabetes, hypothyroidism, or intestinal absorption disorders such as inflammatory bowel disease or chronic digestive complaints, which limit efficient absorption.

A deficiency can also develop as a result of taking certain medications, such as anticonvulsants or isoniazid, which lower active pyridoxal 5'-phosphate levels in the body.

Vitamin B6 deficiency – symptoms

The symptoms of vitamin B6 deficiency vary according to how long it has lasted and how severe it is. The most common signs include:

• Fatigue, irritability and difficulty concentrating.
• Dry skin and cracks at the corners of the mouth.
• Anaemia, mental confusion, tingling or numbness in the extremities.
• A weakened immune system or seizures.

In rare or more advanced cases, vitamin B6 deficiency can show itself as seborrhoeic dermatitis, acute or chronic inflammation of the tongue, or inflamed and cracked lips.

Vitamin B6 – long-term risks

If a vitamin B6 deficiency goes untreated for a prolonged period, it can weaken the immune system and increase susceptibility to infection.

An untreated chronic deficiency can also lead to peripheral neuropathy (characterised by numbness, tingling or pain in the hands and feet) and has been linked to cognitive impairment, changes in mental state and a higher risk of emotional imbalances.

Vitamin B6 – supplements and how to take them

Although studies have linked vitamin B6 supplementation to many benefits, it should be approached responsibly – according to individual needs and your doctor's recommendations – in order to avoid side effects.

Vitamin B6 – when supplements are recommended

A common situation in which vitamin B6 supplements are recommended is a deficiency confirmed by blood tests. They may also be indicated during periods of increased need, such as pregnancy and breastfeeding, or in cases of severe premenstrual syndrome, where they can help ease emotional and physical symptoms.

Supplements may also be considered for people undergoing long-term treatment – neurological treatment, for example – that interferes with the absorption of vitamin B6. Sometimes supplementation is used to improve energy levels and nervous balance.

Vitamin B6 – types of supplement

Vitamin B6 is available as a supplement in many forms – either on its own or as part of a vitamin B complex or a multivitamin.

You'll find it as tablets and capsules, which in most cases are sufficient to correct a deficiency, as well as solutions and injectable ampoules for specific medical situations.

The form and dosage depend on age, sex, state of health and individual requirements.

Vitamin B6 – absorption and useful combinations

Vitamin B6 is absorbed more efficiently when taken alongside magnesium, as the two have complementary effects on the nervous and muscular systems. Combining it with vitamins B1, B9 and B12 is also advisable to support the optimal functioning of energy metabolism and the nervous system.

It's important to limit alcohol while taking it, as excessive consumption can reduce the effectiveness of supplementation by adversely affecting the body's absorption of vitamin B6.

Vitamin B6 – risks and side effects of excess

Although it's a water-soluble vitamin that the body doesn't store, with any excess excreted in the urine, taking excessively high doses over the long term can have negative consequences.

Vitamin B6 – chronic overdose

Chronic vitamin B6 overdose generally involves doses above 200 mg per day and has been linked to the development of peripheral neuropathy. This manifests as numbness, tingling, muscle weakness and balance problems, which usually appear gradually but can become persistent if excessive supplementation continues over the long term.

Vitamin B6 – interactions with medication

Vitamin B6 can interact with certain treatments – either by reducing their effectiveness or by being affected by them. The medications best known for such interactions include anticonvulsants, certain antibiotics and oral contraceptives.

Vitamin B6 – safety recommendations

To avoid overdosing and side effects, vitamin B6 should only be taken under medical supervision, once tests have confirmed a deficiency or an increased requirement. It's important not to exceed the recommended daily dose and to review your individual needs regularly so the dosage can be adjusted accordingly.

Vitamin B6 – frequently asked questions (FAQ)

Although vitamin B6 is one of the most thoroughly studied vitamins in the B complex – thanks to its active form's involvement in over 100 enzymatic reactions – questions keep cropping up about how to take it, its safety and the benefits of supplementation. Below you'll find explanations that will hopefully answer your most pressing questions:

Can you take vitamin B6 every day?

Yes, vitamin B6 can be taken daily, as long as the dose falls within the range recommended by your doctor. Ideally, your daily intake should come from your diet, with supplements used only if you have a deficiency or an increased requirement.

What happens if you take too much vitamin B6?

Taking high doses over the long term can lead to peripheral neuropathy – a condition that manifests as tingling, numbness and loss of sensation in the hands and feet.

What's the difference between natural and synthetic vitamin B6?

The difference between vitamin B6 found naturally in food and the synthetic version lies in the form in which it enters the body. Foods contain forms such as pyridoxine, pyridoxal and pyridoxamine, which are metabolised efficiently, whereas supplements usually contain pyridoxine, which must first be converted in the liver into the active form, PLP, before the body can use it.

Does vitamin B6 help with sleep?

Yes, vitamin B6 can help improve sleep quality, as it's involved in the synthesis of serotonin and melatonin – two messengers essential to regulating the body clock.

Which foods contain the most vitamin B6?

The foods with the highest vitamin B6 content include chicken and turkey, fish (salmon, tuna), liver, chickpeas, potatoes, bananas, sunflower seeds and wholegrain cereals.

What role does vitamin B6 play in pregnancy?

During pregnancy, vitamin B6 is important for the development of the foetus's nervous system and for protein metabolism, but it's also frequently recommended to ease nausea in the first trimester. The recommended dose is higher during this time, though supplementation should only be undertaken on medical advice.

How does vitamin B6 work in combination with magnesium?

Vitamin B6 improves the absorption of magnesium, and together they can help lower the risk of hyperhomocysteinaemia as well as reduce stress, irritability, muscle cramps and premenstrual symptoms.

When does vitamin B6 deficiency occur?

Vitamin B6 deficiency most commonly occurs with an unbalanced diet, chronic alcohol consumption, intestinal absorption disorders or as a result of taking certain medications. Older people and pregnant women, whose daily requirements are higher, are also at greater risk of deficiency.

Can vitamin B6 help with depression?

Yes, studies show that adequate levels can help reduce depressive symptoms, as vitamin B6 is involved in the synthesis of mood-regulating neurotransmitters such as serotonin and dopamine.

Is vitamin B6 safe in the long term?

Vitamin B6 is safe in the long term when the doses taken correspond to the daily requirement recommended by your doctor. Risks arise with uncontrolled supplementation at high doses over extended periods without professional supervision.

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