
Vitamin B complex is a set of substances that are responsible for providing energy to every cell in the body, formation of new building compounds, metabolism and functioning of the nervous system. It is difficult to estimate the number of processes in which B complex vitamins are involved. How to recognise a deficiency of B complex vitamins? Where is vitamin B found in food? Who should supplement it?
What is a vitamin B complex?
Vitamin B complex or compostitum is not a single vitamin, but a set of several different substances of the water-soluble vitamin group. The B vitamin complex consists of eight vitamins:
- B1 - thiamine,
- B2 - riboflavin,
- B3 - niacin,
- B5 - pantothenic acid,
- B6 - pyridoxine,
- B7 - biotin,
- B9 - folic acid,
- B12 - cobalamin.
Each vitamin in the B complex has its specific role, but all of them are involved in cell metabolism, the production of energy from nutrients and the functioning of the nervous system as well as the brain. These common functions are the reason why the individual B vitamins have been grouped and named the B complex.
The B vitamin complex is responsible for: the functioning of the immune system as well as every cell in the body, growth of red blood cells, energy supply to cells, brain function, digestion, appetite, hormone production, cholesterol production, cardiovascular function, muscle tone, fetal brain development during pregnancy, relieving nausea in pregnant women and increasing testosterone levels among men.
Recommended products with B vitamins
Vit. B complex - functions of different B vitamins
In general, B complex vitamins function as it has been described before. However, each of the B complex vitamins has its role in the body. What is the effect of the individual B complex vitamins?
Vitamin B1 (thiamine) is a coenzyme in the metabolism of amino acids and carbohydrates necessary for energy production. It participates in the transmission of nerve impulses. Large amounts of vitamin B1 are found in tissues that intensively consume energy - skeletal muscles, heart muscle, brain, liver and kidneys.
Vitamin B2 (riboflavin) is involved in the release of energy stored in nutrients and oxidation-reduction processes.
Vitamin B3 (niacin) produces the important coenzymes NAD and NADP, which participate in over 50 oxidation-reduction reactions. It is also involved in aerobic and anaerobic energy production, production of fatty acids, cholesterol, sex hormones and cortisol, as well as DNA repair.
Vitamin B5 (pantothenic acid) is a component of coenzyme A (CoA), which takes part in numerous transformations related to the energy metabolism of the body. Pantothenic acid participates in the production of cholesterol, steroid hormones, vitamins A and D, haemoglobin and neurotransmitters.
Vitamin B6 (pyridoxine) is a co-factor for more than 100 enzymes that are primarily involved in the metabolism of amino acids, glycogenolysis, gluconeogenesis and fat, as well as the synthesis of heme and neurotransmitters.
Vitamin B7 (biotin) is a component of many enzymes involved in various metabolic processes. Biotin influences the correct development of the organism as well as the condition of the skin and hair growth.
Vitamin B9 (folic acid) is essential for DNA synthesis, protein and DNA methylation, production of phospholipids, proteins and blood cells. Without vitamin B9 proper growth and development of the body are impossible. Vitamin B9 is particularly important during pregnancy, and its deficiency is responsible for defects in the nervous system of the fetus.
Vitamin B12 (cobalamin) along with vitamin B9 is involved in the production of red and white blood cells, genetic material, amino acids and bone marrow proteins. It takes part in the metabolism of carbohydrates and fats. It ensures the proper function of the nervous system and digestive tract.

What does vitamin B complex help?
Apart from playing a key role in the functioning of the body, vitamin B complex may help in some diseases - prevent Parkinson's disease, protect against various types of cancer, improve mood, reduce symptoms of stress, reduce anxiety, reduce the frequency of migraines and contribute to the reduction of fatigue.
The body's requirement for vitamin B complex
The need of the body for B-complex vitamins strictly depends on age and physiological state, as well as to a large extent on the level of physical activity and daily supplied calories. The more nutrients you eat, the more vitamin B complex your body requires. It is due to the metabolic activity of vitamin B compositum.
Requirements for the B vitamin complex are not set in general, but separately for each of the vitamins. The necessary amounts of the B complex vitamins that should be supplied to the body every day are shown in the table.
Daily requirement for the vitamin B complex (RDA, AI infants only)
Group | B1 | B2 | B3 | B5 (AI) | B6 | B7 (AI) | B9 | B12 |
Infants up to 6 months | 0,2 mg | 0,3 mg | 2 mg | 2 mg | 0,1 mg | 5 μg | 65 μg | 0,4 μg |
Infants up to 1 year | 0,3 mg | 0,4 mg | 5 mg | 3 mg | 0,4 mg | 6 μg | 80 μg | 0,5 μg |
Children up to 3 years | 0,5 mg | 0,5 mg | 6 mg | 4 mg | 0,5 mg | 8 μg | 150 μg | 0,9 μg |
Children up to 6 years | 0,6 mg | 0,6 mg | 8 mg | 4 mg | 0,6 mg | 12 μg | 200 μg | 1,2 μg |
Children up to 9 years | 0,9 mg | 0,9 mg | 12 mg | 4 mg | 1,0 mg | 20 μg | 300 μg | 1,8 μg |
Boys up to 12 years | 1,0 mg | 1,0 mg | 12 mg | 4 mg | 1,2 mg | 25 μg | 250 μg | 1,8 μg |
Boys up to 15 years | 1,2 mg | 1,3 mg | 16 mg | 5 mg | 1,3 mg | 25 μg | 330 μg | 2,4 μg |
Boys up to 18 years | 1,2 mg | 1,3 mg | 16 mg | 5 mg | 1,3 mg | 25 μg | 330 μg | 2,4 μg |
Girls up to 12 years | 1,0 mg | 1,0 mg | 12 mg | 4 mg | 1,2 mg | 25 μg | 300 μg | 1,8 μg |
Girls up to 15 years | 1,1 mg | 1,1 mg | 14 mg | 5 mg | 1,2 mg | 25 μg | 400 μg | 2,4 μg |
Girls up to 18 years | 1,1 mg | 1,1 mg | 14 mg | 5 mg | 1,2 mg | 25 μg | 400 μg | 2,4 μg |
Men from 19 years of age | 1,3 mg | 1,3 mg | 16 mg | 5 mg | up to 50 years of age 1.3 mg, over 50 years of age 1,7 mg | 30 μg | 400 μg | 2,4 μg |
Women from 19 years of age | 1,1 mg | 1,3 mg | 14 mg | 5 mg | up to 50 years of age 1.3 mg, over 50 years of age 1,5 mg | 30 μg | 400 μg | 2,4 μg |
Pregnant women | 1,4 mg | 1,4 mg | 18 mg | 6 mg | 1,9 mg | 30-35 μg | 600 μg | 2,6 μg |
Breastfeeding women | 1,5 mg | 1,6 mg | 17 mg | 7 mg | 2,0 mg | 30-35 μg | 500 μg | 2,8 μg |
Symptoms of B complex deficiency
The effect of vitamin B complex concentrates on supplying energy to every cell of the body, forming cell structures, genetic material, red and white blood cells, neurotransmitters and hormones. Therefore, symptoms of B complex deficiency are seen in the skin (abnormal reconstruction of cell structures), the nervous system (deficiency of neurotransmitters) and the digestive tract (control of nutrient metabolism).
A deficiency of a set of B vitamins can manifest itself:
- skin rashes,
- cracks around the mouth and flaky skin on the lips,
- swollen tongue,
- chronic fatigue,
- weakness,
- anaemia,
- a feeling of disorientation,
- irritability,
- depression,
- nausea,
- abdominal cramps,
- diarrhoea,
- constipation,
- numbness or tingling in the feet and hands.
With vitamin B complex deficiency, the risk of anaemia, digestive problems, skin disorders, infections and peripheral neuropathy increases.
Źródła witamin B kompleks w żywności
B vitamins are common in food. If you follow a well-balanced diet, you are unlikely to worry about not getting enough of the B complex vitamins you require The exceptions are the period of pregnancy (vitamin B9) and competitive physical activity, where nutrient energy consumption is very high. The only group at risk of nutritional deficiencies of vitamin B complex daily are vegans and to a lesser extent vegetarians. Often, the best sources of B vitamins are animal products, and in the case of vitamin B12, the absorbable form can only be found in them. This is why people on vegetarian and vegan diets need to supplement vitamin B12, and preferably the entire vitamin B complex as a preventative measure. Moreover, the excess of B vitamins is excreted from the body regularly and does not cause any damage. Obviously with rational supplementation and taking the recommended doses.
More and more often, vitamin B complex supplementation is recommended for elderly people, but only if they experience loss of appetite or follow a monotonous diet.
In addition, people with certain medical conditions may benefit from daily supplementation with B complex vitamins. These include: alcohol addiction, autoimmune diseases such as lupus, rheumatoid arthritis or type 1 diabetes, depression, diabetes, malabsorption disorders such as celiac disease or Crohn's disease, kidney disease, HIV, heart disease, Alzheimer's disease, AIDS, cancer.

The best sources of B vitamins in food are:
- B1 – meat, liver, meat products, pulses, whole grain cereal products, nuts
- B2 – milk, ripened cheese, quark, eggs, offal, whole grain cereals, green leafy vegetables and cruciferous vegetables
- B3 – liver, meat, fish, peanuts, whole grain products (only about 25% of niacin is absorbed from plant sources)
- B5 – meat, fish, wholemeal cereals, dry pulses
- B6 – fish (mainly oily sea fish), meat, liver, pulses, nuts, seeds, garlic, ginger, whole grain cereals, brown rice, bananas, red peppers, sauerkraut, potatoes
- B7 – milk, vegetables, meat, cereals, eggs
- B9 – leafy green vegetables, cabbage, brussels, broccoli, cauliflower, dry pulses, liver, eggs
- B12 – meat, fish, dairy products, offal