The B vitamins perform numerous functions, all different and essential for the human body. The B group includes Thiamine (Vit. B1), Riboflavin (Vit. B2), Niacin or Vitamin PP (Vit. B3), Pantothenic Acid (Vit. B5), Pyridoxine (Vit. B6), Biotin (Vit. H), Folic Acid (Vit. B9) and Cobalamin (Vit. B12).

Thiamine plays an essential role in the metabolism of carbohydrates, fats and proteins, intervening in dozens of chain reactions. Thiamine is very common in foods of animal and vegetable origin. Being water-soluble, a large amount of thiamine is lost during cooking. Thiamine deficiency causes disturbances in carbohydrate metabolism, a syndrome called beriberi characterized by disorders of the nervous, cardiovascular and gastrointestinal systems.

Riboflavin acts in the growth processes of various body tissues and in the formation of antibodies. It is very common in both plant and animal foods, such as green leafy vegetables, brewer's yeast, liver and milk. Riboflavin deficiency can cause growth arrest, dermatitis, lesions on the edges of the lips and eye diseases.

Niacin, through its metabolites, is involved in a large number of biological processes including energy production, synthesis of fatty acids, cholesterol and steroids. In nature it is present in meat (especially red meat), poultry, fish, legumes and cereals. Niacin deficiency causes pellagra, i.e. dermatitis, diarrhea and dementia.

Pantothenic acid is the precursor of coenzyme A, which is crucial for the metabolism of carbohydrates, amino acids and fatty acids. It participates in the synthesis of hemoglobin, cholesterol and some hormones. Pantothenic acid is widely distributed in plant or animal foods. Given the diffusion of the vitamin in nature, deficiency is rare and is related to serious dietary deficiencies or alterations in intestinal absorption.

Pyridoxine participates in the metabolism of carbohydrates and essential fatty acids, amino acids and nitrogenous substances. In nature it is present in both plant-based foods (cereals, legumes, vegetables) and animal products and derivatives (liver, eggs, milk, cheese). It is also synthesized by the intestinal flora. Deficiency states are rare and can cause irritability, muscle cramps and convulsions.

Biotin is involved in fatty acid biosynthesis, gluconeogenesis, energy production and branched chain amino acid metabolism. Some nutritional sources of biotin are: egg yolk, liver, milk, soy and barley. Biotin deficiency is very rare, however in subjects with short bowel syndrome, it can manifest itself with generalized erythematous skin rashes, alopecia, conjunctivitis and neurological disorders.

Folic acid is involved in several critical biological processes, including the synthesis of DNA, RNA, and proteins. In nature, folates are found in leafy vegetables (spinach, cabbage, turnips, escarole, beets, Swiss chard, dandelion, radicchio), oranges, lentils, asparagus, orange juice, and broccoli. A deficiency of this vitamin can cause anemia, asthenia, easy tiredness, irritability, headache, difficulty concentrating, cramps, and palpitations.

Vitamin B12 is necessary especially in the production of red blood cells, consequently the most obvious sign of its deficiency is a form of anemia. Vitamin B12 is present in minimal doses in all foods of animal origin, while the liver is very rich in it. It is completely absent in vegetables. Vitamin B12 deficiency can occur in the case of a vegetarian diet or in situations of excessive consumption such as breastfeeding or pregnancy with the risk of serious neurological damage to the unborn child.