Vitamin B: signs of deficiency, advice and recommended foods

Group B vitamins are essential and indispensable to our bodies. There is not just one B vitamin, but a family of 8: B1, B2, B3, B5, B6, B8, B9 and B12.

Group B vitamins are involved in the transformation of carbohydrates, lipids and proteins and play a part in energy metabolism (energy production) and the proper functioning of the nervous system. They play a major role in reducing fatigue, improving memory and promoting sleep. They are also involved in cell regeneration, DNA repair and oxygen transport.

B vitamins are also important for healthy skin, eyes and hair.

Vitamin B1 is essential for the heart, muscles and nerves to function properly. It is involved in the metabolism of carbohydrates, proteins and lipids.

Riboflavin helps protect cells from oxidative stress. It is involved in the metabolism of carbohydrates and amino acids. It also contributes to the health of mucous membranes.

Niacin, formerly known as vitamin PP, is involved in the production of energy within cells, and in the synthesis of fatty acids and sex hormones. It is involved in repairing DNA if it is damaged, and is also involved in the proper functioning of the nervous system.

Vitamin B5 is a major component of coenzyme A, which plays a key role in the cell and tissue repair mechanism. It is involved in the transport of oxygen in the blood, the synthesis of cholesterol fatty acids, certain sex hormones, vitamin D and certain neurotransmitters.

This vitamin also plays an active role in the formation and regeneration of skin and hair.

Vitamin B6 is involved in DNA synthesis, in the transport of oxygen in the blood via haemoglobin, in many neurotransmitters, and in the metabolism of proteins and glycogen.

It plays a part in the normal functioning of the nervous system, in the regulation of hormonal activity and in the normal functioning of the immune system.

It also contributes to healthy skin.

In terms of health, biotin is involved in the energy production process. It is involved in the metabolism of lipids, carbohydrates and proteins, and in particular in the oxidation of glucose.

biotin (vitamin B8) also helps to maintain normal hair, skin and mucous membranes.

Involved in cell growth and regeneration, this vitamin is routinely prescribed before and during pregnancy. Vitamin B9, also known as folic acid or folates, is involved in the normal growth of the foetus and the proper development of the nervous system, and helps to prevent stunted growth or serious malformations in the unborn baby.

Essential for the formation and maturation of red blood cells, DNA synthesis, the functioning of the central nervous system and support for the immune system, vitamin B12 also acts as a coenzyme in numerous metabolic functions.

Significant thiamine deficiency can be detected by signs of fatigue, weight loss,irritability, memory problems, loss of appetite, etc. A severe thiamine deficiency will affect the nerves, muscles, heart and brain.

The people most prone to serious vitamin B1 deficiency are young adults with severe anorexia, people who consume large quantities of alcohol and people whose diet lacks variety and is essentially made up of highly processed carbohydrates (white rice, white flour, white sugar).

Certain conditions, such as prolonged diarrhoea, can also lead to a vitamin B1 deficiency.

The symptoms of a lack of vitamin B2 are often recognisable by cracks in the mouth and crazing of the lips. Sometimes the tongue can turn a magenta red, suggesting a riboflavin deficiency. Finally, seborrhoeic dermatitis may appear on the ears, around the nose, between the nose and mouth and on the eyelids.

Loss of appetite, headaches, dizziness, mood disorders, fatigue, digestive discomfort and vomiting can all be signs of niacin deficiency.

A dark red rash may also appear on the hands, feet, calves, neck and face.

This very rare deficiency can cause fatigue, headaches, tingling and insomnia. Severe hair loss may also suggest a deficiency in B vitamins.

Chapped lips, seborrhoeic dermatitis, a red tongue, tingling and numbness in the hands and feet may suggest symptoms of vitamin B6 deficiency.

Brittle, fragile nails, acne, hair loss (alopecia), an oily scalp, dermatitis and skin problems are all common symptoms that can indicate a biotin deficiency. Recurrent conjunctivitis or muscle cramps can also indicate a lack of vitamin B8.

Symptoms of vitamin B9 deficiency frequently include dizziness, paleness, headaches,shortness of breath and fatigue.

Vitamin B12 deficiency can occur in people who do not eat any animal products, and is more common in vegan and sometimes vegetarian diets . It can be recognised by paleness, frequent shortness of breath, difficulty concentrating and severe fatigue.

Severe thiamine deficiency can lead to a serious disease called beriberi. This disease causes neurological disorders and heart failure.

Severe riboflavin deficiency often occurs in the context of malnutrition. This deficiency causes painful cracking at the corners of the mouth and on the lips, sometimes with a numb tongue.

A long-term deficiency in vitamin B3 (Niacin) can lead to the development of pellagra, a nutritional disorder often linked to malnutrition, the symptoms of which include dermatitis, diarrhoea and, in the most severe cases, depression and dementia.

The risks of a vitamin B5 deficiency are low if you eat a balanced and varied diet. A vitamin B5 deficiency can lead to hair loss.

This deficiency can cause a burning sensation under the feet, insomnia, cramps, fatigue, headaches and tingling.

Vitamin B6 deficiency, if linked to malabsorption of this vitamin, can cause epileptic seizures, scaly skin rashes, cracks at the corners of the mouth and tingling sensations in the feet and hands.

A lack of vitamin B8 can lead to skin problems, brittle nails, fatigue, abnormal hair loss, conjunctivitis and muscle cramps.

During pregnancy, a vitamin B9 deficiency increases the risk of embryonic malformation.

A vitamin B9 deficiency can also lead to an anaemia known as "megaloblastic", characterised by the presence of abnormally large red blood cells with poorly differentiated cell nuclei.

Vitamin B12 is often lacking in vegan or vegetarian diets because it is only found in foods derived from animals (offal, eggs, cheese, white meat and red meat). Vegans will therefore need to take vitamin B12 supplements.

Vitamin B12 deficiency is not just a problem for vegans and vegetarians, but also for people suffering from certain conditions that lead to malabsorption of vitamin B12 in the digestive tract, such as Biermer's disease.

Vitamin B12 deficiency can cause anaemia, memory problems and mental confusion (in the case of severe deficiency).

Severe vitamin B12 deficiency can lead to nerve damage, muscle weakness, loss of reflexes and motor difficulties.

If you are suffering from symptoms suggestive of a deficiency, do not hesitate to consult your doctor, who will be able to make a full diagnosis and prescribe appropriate treatment.

The best source of B vitamins? A balanced and varied diet! To avoid deficiencies in group B vitamins, the first thing to think about is what you eat. Eat fresh, seasonal vegetables, wholegrain cereals and seeds every day, and vary your sources of animal protein (think free-range eggs from organic hens if possible, which are economical and rich in micronutrients).

For vegetarian and especially vegan diets, vitamin B12 supplementation is essential, as this vitamin is only found in animal products. Vitamin B12 can be found in vitamin complexes (such as Brewer's yeast) that meet the recommended daily requirement (RDA) or in vegan vitamin B12 food supplements (produced by natural bacterial fermentation processes). These supplements are available in ampoule or tablet form.