Vitamin B: introduction, types, benefits, foods, deficiency and overdose


In this article, we will introduce in detail about different types of vitamin B, foods source,  the benefits to the human body, intake standard, the symptoms of variety vitamin B deficiency and overdose.


What is vitamin B?

Vitamin B is a general term for a group of vitamins with the same function. It has more than 12 kinds, among which 9 kinds of vitamins are recognized as essential for the human body. all of them are water-soluble vitamins. Pregnant women or babies lack vitamin B, which is prone to skin diseases such as peeling of the hands and feet, eczema, and stomatitis(mouth ulcer). Therefore, vitamin supplements for pregnant women and babies cannot be ignored. Each B vitamin has its own unique effect. It is an essential nutrient for human tissues, all of which are coenzymes. It is involved in the metabolism of sugar, protein, and fat in the body as well. 

Vitamin B group is an indispensable substance to promote metabolism and convert sugar, fat, and protein into heat. If vitamin B deficiency occurs, cell function is immediately reduced, causing metabolic disorders. At this time, the human body will be stagnant and loss of appetite. Excessive drinking leads to liver damage, which in many cases occurs in parallel with vitamin B deficiency. Vitamin B supplementation can soothe your mood.

Vitamin B types, benefits, foods, deficiency and overdose
Vitamin B types, benefits, foods, deficiency and overdose

The human body cannot manufacture synthetic vitamin B by itself and must be replenished from the outside. Life and work stress, improper eating habits or the use of certain drugs, the B vitamins in the body will be quickly consumed. Plus the B vitamins themselves are soluble in water and therefore consume faster. B vitamins can help maintain heart and nervous system function, maintain the health of the digestive system and skin, participate in energy metabolism. It also enhances physical strength and nourishes the body.

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Types and categories

Vitamin B and vitamin C belong to water-soluble vitamins.

Essential vitamin B for the human body

Vitamin name Chemical name or alias Note
Vitamin B1 Thiamine
Vitamin B2 Riboflavin Form FMN, FAD
Vitamin B3 Niacin, vitamin PP NAD, NADP
Vitamin B5 Pantothenic acid
nicotinic acid
Form CoA
Vitamin B6 Pyridoxine, pyridoxal
Vitamin B7 Biotin (Vitamin H)
Vitamin B9 Folic acid
(Pteroylglutamic acid)
Vitamin B12 Cobalamin,
Coenzyme B12


Other vitamin B

Vitamin name Chemical name or alias Note
Vitamin B4 Adenine, choline, carnitine
Vitamin B8 Inositol
Vitamin B10 Para–aminobenzoic acid (PABA) Also known as Vitamin R
Vitamin B11 Salicylic acid Also known as Vitamin S
Vitamin B13 Also known as orotic acid
Vitamin B14 Betaine a mixture of vitamin B10 and vitamin B11
Vitamin B15 Palanine
Vitamin B16 N,N-dimethylglycine
Vitamin B17 Amygdalin
Vitamin B22
Vitamin B-c Folic acid Is Also known as Vitamin B9
Vitamin B-h Cyclohexanol inositol
Vitamin B-t
Vitamin B-w Biotin
Vitamin B-x P-aminobenzoic acid


Vitamin A(also known as retinol), vitamin D (also known as calciferol), vitamin E (also known as tocopherol) and vitamin K (also known as blood coagulation vitamin) belong to the fat-soluble vitamin.

You may check other vitamins introduction in this article “What is vitamin: A, B, C, D, E, and K“.

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Vitamin B benefits

Different vitamins B have different effects. Below we will briefly introduce their effects to the human body.

Vitamin B1~B5

Vitamin B1: The physiological function of vitamin B1 is to increase appetite and maintain normal nerve activity. It is converted into thiamine pyrophosphate (also known as co-carboxylase) in the body. It participates in the metabolism of sugar. Therefore, when vitamin B1 is deficient, the oxidation of sugar in tissues is affected. In addition, it also has the effect of inhibiting cholinesterase activity.

Vitamin B2: It is an important component of many enzyme systems in the body.  It is involved in the metabolism of matter and energy. It promotes the development and regeneration of cells and maintains the normal growth of skin, nails, and hair. It also helps eliminate inflammation in the mouth, lips, and tongue. Vitamin B2 improves vision and reduces eye fatigue.  In addition, it can interact with other substances to help the metabolism of carbohydrates, fats, and proteins.

Vitamin B3: It is not only a vitamin that maintains the health of the digestive system, but also an indispensable substance for sex hormone synthesis. It promotes the health of the digestive system, reduces gastrointestinal disorders; makes the skin healthier; prevents and relieves a severe migraine; promotes blood circulation, lowers blood pressure; reduces diarrhea.

Vitamin B5: It participates in the production of energy in the body and can control the metabolism of fat. It is an essential nutrient for the brain and nerves. It is resistant to stress, cold, and infection, prevents the toxicity of certain antibiotics, and eliminates postoperative bloating.  VitaminB5 also has the function of making antibodies that keep blood, skin, and hair healthy.

Vitamin B6~B12

Vitamin B6: It has functions such as inhibiting vomiting and promoting body development. The vitamin B6 deficiency can cause vomiting, cramps and other symptoms. It includes three substances, namely pyridoxine, pyridoxal, and pyridoxamine. Pyridoxine is converted to pyridoxal in the body, and pyridoxal and pyridoxamine can transform each other.

Vitamin B7: It is essential for the synthesis of vitamin C. It is an indispensable substance for the normal metabolism of fats and proteins, and it can enhance the body’s immune response and resistance. It is a water-soluble vitamin necessary to maintain the body’s natural growth and normal body functions. Vitamin B7 also can help to control diabetes.

Vitamin B9: It involves cell proliferation, reproductions. It has a significant impact on the differentiation and maturation of blood cells, fetal development (blood cell proliferation and fetal neurodevelopment).  Vitamin B9 can protect the heart’s blood vessels by avoiding the accumulation of semi-associated cysteine. It may also slow the onset of Alzheimer’s disease.

Vitamin B12: It promotes the development and maturation of red blood cells. It can keep the body hematopoietic function in a normal state and prevent pernicious anemia. Vitamin B12 also acts as a coenzyme to increase the utilization of folic acid. It promotes the metabolism of carbohydrates, fats, and proteins. Vitamin B12 plays an important role in the growth and development of infants and young children. It also has the effect of eliminating irritability, improves concentration, enhances memory ability. Vitamin B12 is a vitamin that is indispensable for the function of the nervous system. It involves in the formation of a lipoprotein in nerve tissue and maintains the health of the nervous system.

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How much vitamin B do I need to take?

These data are provided for adults only. Vitamin B intake has the difference between children, pregnant women, and breastfeeding women.

  • B1 requires about 1.5 mg per day.
  • B2 requires about 2 to 4 mg per day.
  • B3 requires about 13 to 19 mg per day.
  • B5 requires about 5 to 10 mg per day.
  • B6 requires about 1.5 to 2 mg per day.
  • B7 requires about 0.03 mg for men and 0.01 mg for women.
  • B9 requires about 400mcg per day.
  • B12 requires about 12μg (1/1000mg) per day.

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What are vitamin B foods?

Vitamin B1 is mainly found in the seed coat and germ, such as rice bran. It is also abundant in mushroom, lean meat, cabbage, and celery. Vitamin B1 is easily soluble in water and can be lost through water during food cleaning.

Vitamin B2 is abundantly found in animal livers and kidneys, grains, vegetables, milk, and fish.

Vitamin B3 is widely found in animal and plant foods. It comes from the animal liver, kidney, lean meat, whole grains, beans and so on. Vitamin B3 is the only vitamin that can be synthesized in animal tissues and is synthesized by tryptophan.

Vitamin B5 is high in milk, followed by nuts, chicken, animal kidneys and heart (such as beef, beef heart, sheep heart, pork), green leafy vegetables and so on.

Vitamin B7 is widely found in food. Egg yolks, liver, milk, mushrooms, and nuts are also the best sources of vitamin B7. Vitamin B7 cannot be artificially synthesized.

Vitamin B9 is naturally found in animals and plants, especially in yeast, liver and green leafy vegetables.

Vitamin B12 is important for cell division and protein synthesis. It is widely found in animal foods such as chicken, beef, and lamb. Vitamin B12 deficiency is generally not present except for patients with gastrointestinal problems and picky pregnant women.

(You can get more information about what foods contain other vitamins from this article “What are foods that have vitamin A, B, C, D, E, and K?“.)

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Vitamin B deficiency symptoms

Vitamin B1 deficiency: Loss of appetite, gastrointestinal disease, dry hair, memory loss, cramps (muscle spasms) indicates that you may be deficient in vitamin B1.

Vitamin B3 deficiency: It can cause ecdysis, which is mainly characterized by dermatitis, diarrhea, and dementia. Some people also have anorexia, indigestion, oral mucosal erosion, depression, anxiety, memory loss, muscle tremors and so on.

Vitamin B5 deficiency: It mainly manifests as irritability, headache, depression, restlessness, fatigue, coldness, poor sleep, nausea, vomiting, abdominal pain, numbness, muscle cramps, abnormal feelings of the hands and feet, muscle weakness, gait shaking, and hypoglycemia.

Vitamin B6 deficiency: It can appear weak, expressionless, apathetic, lethargy, depression, loss of responsibility, nervousness, irritability. A small number of people have sensory peripheral neuropathy, poor motor function, difficulty walking, and weight loss. The baby will have convulsions.

Vitamin B7 deficiency: It can lead to perioral dermatitis, conjunctivitis, hair loss (eyebrows, eyelashes, hair), tongue nipple atrophy, dry skin, numbness, depression, fatigue, muscle pain, and uncoordinated movements.

Vitamin B9 is deficiency: It can lead to megaloblastic anemia: It can cause fatigue, dizziness, shortness of breath, palpitation, smooth tongue, loss of taste, loss of appetite, numbness of hands and feet, abnormal sensation, gait instability, difficulty walking, apathy, depression, lethargy or Insanity. Vitamin B9 deficiency may occur in fetal neural tube defects when infancy. In addition, pregnant women can also lead to pre-eclampsia, placental abruption, spontaneous abortion, fetal growth retardation, premature birth, low birth weight of newborns.

Vitamin B12 deficiency: It can cause megaloblastic anemia, nervous system damage, depression, memory loss, limb tremor, and hyperhomocysteinemia.

NOTE: the Single article cannot summarize all vitamin B deficiency symptoms and treatment. We will gradually introduce the causes of vitamin B deficiency, prone population groups, symptoms, treatment methods and so on in future articles.

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Vitamin B overdose (intoxication) symptoms

Vitamin B1 overdose (intoxication): When taking more than 5 to 10 g per day, occasionally side effects such as trembling, herpes, edema, nervousness, rapid heartbeat, and allergies may occur.

Vitamin B2 overdose (intoxication): Excessive intake may cause itching, paralysis, nosebleeds, burning sensation, stinging.

Vitamin B3 overdose (intoxication): skin flushing, itching, gastrointestinal reactions, mild liver dysfunction and visual impairment.

Vitamin B5 overdose (intoxication): No valid medical data are available for now.

Vitamin B6 overdose (intoxication): Excessive intake can lead to neuropathy. In the worst case, the skin loses consciousness.

Vitamin B9 overdose (intoxication): Taking large doses of folic acid may interfere with the effects of anticonvulsants and induce seizures in patients. Oral folic acid 350mg may affect the absorption of zinc, resulting in zinc deficiency, fetal growth retardation, and low birth weight infants. It masks the early manifestations of vitamin B12 deficiency and causes damage to the nervous system.

Vitamin B12 overdose (intoxication): Overdose of vitamin B12 can cause allergic reactions such as asthma, urticaria, eczema, facial edema, and chills. It may also be secondary to nerve excitement, precordial pain, and palpitations. Excessive intake of vitamin B12 can also lead to a deficiency of folic acid.

Note: As with the vitamin B deficiency chapter, we will introduce in detail in the following articles the symptoms and treatment methods of each vitamin B overdose.

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  • B Vitamins: MedlinePlus. address

Write and Review

  • Written by Nurmemet, MD (Emergency Medicine Specialist)
  • Medically reviewed by Merhaba, MD (Pediatrician)



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