Vitamin B is a group of 8 fat-soluble vitamins, which play an important role in the cellular metabolism. They are chemically and biologically distinct but they coexist in several food items. The functions, effects and side effects of each of these vitamins are separate, and hence their dosages and deficiencies vary. Let’s have a look at each one of them.

  1. Types of Vitamin B
  2. Vitamin B Dosage
  3. Benefits of Vitamin B complex
  4. Vitamin B Food Sources
  5. Vitamin B side effects
Doctors for Vitamin B: Sources, Foods, Benefits and Side Effects
Let's have a look at the functions of each component of vitamin B and their deficiency symptoms
Type of vitamin B Functions Deficiency
B1 Thiamine Helps in proper nerve functions and synthesis of DNA and RNA. Beri Beri (oedema, weight loss, pain in limbs, emotional disturbances, irregular heartbeat)
B2 Riboflavin Release of energy in the body. Ariboflavinosis (cracked lips, swelling in tongue, sore throat, swelling in the mouth)
B3 Niacin Involved in energy transfer within the body. Pellagra (swelling of the skin, difficulty in falling asleep, weakness, mental confusion)
B5 Pantothenic Acid Synthesis of amino acids (proteins), cholesterol and hormones Acne and feelings of tingling or numbness of the skin
B6 Pyridoxine Synthesis of neurotransmitters Inflammation of the skin, pink eye, risk of epilepsy and other neurological disorders
B7 Biotin Essential for the healthy functioning of the nervous system and generation of energy Impaired growth and neurological disorders in infants
B8 Inositol Important in periods of rapid division and growth, like pregnancy and infancy Anaemia; Deficiency during pregnancy can lead to birth defects
B12 Cobalamin Important for the production of RBCs (red blood cells), DNA synthesis and maintaining nerve cells and blood cells. Anaemia; can cause memory loss and cognitive defects in the elderly due to reduced absorption

Table 1

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Daily dosage of Vitamin B is given below. You must, however, note that these values are approximate and the actual dosage of the vitamin depends on your age, gender, sex and other physical traits. You are highly recommended to consult with your physician before taking any external supplements of this vitamin. While consuming it in the natural or dietary forms, try not to exceed the RDA (recommended daily allowance) values.

Type of vitamin B RDA Males RDA Females
B1 Thiamine 1.2 mg 1.1 mg
B2 Riboflavin 1.3 mg 1.1 mg
B3 Niacin 16 mg 14 mg
B5 Pantothenic Acid 5 mg 5 mg
B6 Pyridoxine 1.3 mg 1.3 mg
B7 Biotin 30 mg 30 mg
B8 Inositol 400 mg 400 mg
B12 Cobalamin 2.4 mg 2.4 mg

Let's discuss the individual health benefits of each of the components of vitamin B complex.

  • B1: Vitamin B1 has neuroprotective effects against Parkinson ’s and it helps in the formation of the myelin sheath, a protective covering around neurons (brain cells). It also acts as an analgesic and used for pain reduction in dysmenorrhoea.
  • B3: It reduces the risk of cardiovascular diseases by reducing oxidative damage to the heart and lowering cholesterol levels.
  • B5: Also known as pantothenic acid, vitamin B5 has an important role in RBC formation and thus has a preventive action against anaemia. Deficiency of this vitamin increases the risk of cardiovascular problems such as heart attack and stroke.
  • B6: Vitamin B6 is a natural pain-killer. It boosts metabolism and helps improve organ function.
  • B7: It has been scientifically proven that supplementation of this vitamin helps prevent hair fall and maintaining the strength and structure of nails.
  • B8: Vitamin B8 is known to be especially beneficial for women since it is used in the treatment of PCOS and is known to promote weight loss in such women. It also reduces the risk of gestational diabetes.
  • B12: Vitamin B12 has several functions and benefits for your body. It protects and helps maintains the health of skin, nails and hair, prevents anaemia, and reduces the risk of hyperpigmentation. This vitamin also prevents dementia and keeps depression and anxiety at bay.

Vitamin B1 benefits

Vitamin B1 or Thiamine is an important part of vitamin B complex and has various health benefits and functions within the body. It is responsible for forming coverings (myelin sheath) around the nerves, which helps in protecting nerves against external damage. This, in turn, has a protective action on your brain.

In a study involving patients with encephalopathy (brain disease causing damage to the brain), researchers found that thiamine was regularly prescribed to patients and its deficiency corresponded with an increased risk of the disease. Similar findings have been observed in patients affected with Parkinson’s disease, which is suggestive of the protective actions of this vitamin on brain function.

Additionally, thiamine is also known to affect pain mechanism and has positive effects on pain reduction. Studies have demonstrated that fibromyalgia, which is characterized by severe musculoskeletal pain is treated with high doses of thiamine to get relief from muscular pain associated with the condition. It was observed that patients suffering from fibromyalgia benefitted from regular thiamine consumption. Due to its positive effects on pain reduction (analgesia), the use of thiamine has been highly recommended in women suffering from dysmenorrhea (painful menstrual cycles) as well. Additionally, several researchers have demonstrated the use of vitamin B1 as adjuvant therapy for the treatment of diabetes mellitus type 2.

Read more: Vitamin B1 deficiency symptoms

Benefits of vitamin B2

As discussed in the functions of this vitamin (see table 1), vitamin B2 helps in maintaining adequate energy levels and thus the normal functioning and activities of the body. It also helps in maintaining the normal levels of other components of vitamin B in the body such as that of B6 and B9. This is enabled by converting them into their active forms which can then be used by the body. 

A study published in the American Journal of Clinical Nutrition demonstrated that riboflavin is essential to ensure adequate blood levels of iron, since it has an effect on the process of utilization of iron by the body. A deficiency of this vitamin is often linked with a high risk of anemia.

Other than this, a specific role of vitamin b2 has been suggested in the management and prevention of migraines. It is often used in the preventive therapy of migraine attacks along with other medications. In fact, vitamin B2 has been successfully used in preventing the frequency and burden of migraine attacks. Due to its success, riboflavin has also been tried in pediatric (children) patients for the prevention of migraines.

Read more: Migraine in children

Vitamin B3 niacin uses

Vitamin B3 or niacin has various health benefits other than being involved in the treatment of pellagra. It improves the functioning of the cardiovascular system (heart and its vessels) and thus helps in the prevention of heart diseases. This, it does so, by reducing the levels of low-density lipoprotein (LDL) and triglycerides and increasing the levels of high-density lipoprotein (HDL) in the body.

Another mechanism by which vitamin B3 improves cardiac health is by reducing oxidative stress and inflammation, which are the major causative agents of cardiac disorders. Due to these benefits, niacin has been used for the prevention of coronary heart diseases for over 40 years and has been recently used for their treatment as well.

Read more: Best cardio exercises for heart health

Vitamin B5 benefits

Vitamin B5 is involved in the synthesis of proteins and cholesterol (refer to table 1) in the body. It thus helps to maintain normal levels of blood cholesterol and is cardioprotective in action. Studies have revealed that vitamin B5 is involved in the production and regulation of RBCs (red blood cells, which form the blood), and is thus used in the treatment of anaemia.

Read more: High cholesterol treatment

Other than this, vitamin B5 or pantothenic acid is also known to have effects on the production and release of certain hormones like cortisol. It reduces cortisol production by the body, which can cause fatigue, muscle pain and joint pain and weight loss. An increase in arthritic pain or an increased risk of hypertension (high blood pressure), stroke and heart diseases are also associated with the deficiency of this vitamin.

Read more: Arthritis symptoms

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Vitamin B6 uses

Vitamin B6 or pyridoxine is an important component of the vitamin B complex family. It is considered to be good for maintaining the normal metabolism of the body, along with proper nerve function and smooth functioning of other organs. It is also used to boost individual levels of energy and thus aids the treatment of chronic fatigue. The most pronounced use of vitamin B6 is as a natural painkiller, for the treatment of several types of pain.

A recent study was conducted to assess the pain-reducing effects of this vitamin. Pyridoxine was administered to patients affected with severe lower back pain, along with other vitamins and analgesics. Results of the study revealed a reduction in pain intensity and an improvement in mobility restoration in these patients.

Read more: Home remedies for body pain

Benefits of biotin (vitamin B7)

The benefits of biotin on hair and skin are well renowned since biotin has been widely used for improving skin and hair health. This vitamin improves the texture of skin and hair and has a particular role in the prevention and treatment of hair fall. It is also commonly used as a nail supplement for the treatment of fragile or malformed nails.

A recent study tested the effects of biotin on uncombable hair syndrome, which is characterized by slow-growing, straw-coloured hair, that is almost impossible to comb apart. Supplementation with biotin in these patients revealed a positive response. A 0.3 mg dose of oral biotin thrice daily demonstrated a significant improvement in these patients within a duration of 4 months. Hair growth rate was also enhanced in them, and an improvement in hair strength and combability was noted.

Read more: Hair growth treatment and tips

Similarly, the effects of biotin on nails have been proven by various studies. One such study demonstrated a 25% improvement in the nail structure and strength in patients with brittle nails with the help of oral biotin supplement. These studies thus prove that biotin is an excellent supplement for hair, nails and skin. Do not use supplements without a prior prescription.

Vitamin B8 benefits

Vitamin B8 or inositol has important health benefits, particularly for women in the reproductive age. It has been widely used in the treatment and management of PCOS (polycystic ovarian disease) and is known to aid in weight loss in these patients. This reduces insulin resistance and the risk of diabetes in them and helps in the improvement of other symptoms.

A study conducted on women living with PCOS revealed that supplementation with inositol was likely to reduce the risk of infertility by increasing the size of oocytes. Inositol supplements have also been proven to improve placental vascularization, which improves the blood flow to the fetus. This helps in improving the outcomes of assisted reproductive techniques in women affected by PCOS.

Read more: What to eat and what to avoid if you have PCOS

It has been acknowledged that the risk of gestational diabetes (diabetic state during pregnancy) is higher in women affected by PCOS. Treatment with inositol is also known to prevent or treat gestational diabetes mellitus in women affected by PCOS.

Other than being beneficial for women, vitamin B8 is also known to reduce blood cholesterol levels in individuals living with metabolic disorders. Studies have revealed that inositol supplementation causes a reduction in the total levels of triglycerides and low-density lipoproteins, associated with hypertension; and an increase in high-density lipoprotein which is protective.

Read more: Foods to reduce and control high cholesterol

Vitamin B12 function

Vitamin B12 or cobalamin is the most familiar vitamin out of the vitamin B complex, known for its countless benefits. The most evident is its role in the treatment and prevention of anaemia. Vitamin B12 deficiency has been very closely linked with the development of pernicious anaemia since vitamin B12 is essential for the formation of RBCs. Other than this, vitamin B12 is also responsible for maintaining good health of skin, nails and hair.

A deficiency of this vitamin has also been associated with hyperpigmentation, changes in hair and nail structure, along with inflammation of the tongue or the mouth. Additionally, vitamin B12 is known to reduce the levels of depression and anxiety and is also preventive against dementia. Mild cognitive impairment is known to be improved by this vitamin since it slows the rate of cognitive decline of the brain.

Read more: Foods that increase brain power

Following are the food sources of all types of vitamin B.

Type of vitamin B Vitamin B food sources
B1 Thiamine Yeast, liver, fish, beans, soybean, peas, tuna, potatoes, mushrooms, sunflower seeds, tomatoes, brinjal
B2 Riboflavin Lamb, milk, milk products, yoghurt, almond, leafy greens, eggs, nuts, rice, whole grains  
B3 Niacin Meat, poultry, fishes like salmon and tuna, cereals, legumes, seeds, peanuts
B5 Pantothenic Acid Eggs, chicken, meat, turkey, fresh fruits and vegetables, particularly mushrooms, whole grains, honey
B6 Pyridoxine Cereals, beans, poultry, fish, fruits and vegetables, green leafy vegetables
B7 Biotin Egg yolk, milk, broccoli, bananas, potatoes, avocado, seeds, soy, cheese, legumes, nuts, pork, leafy greens
B8 Inositol Fruits, vegetables, whole grains, beans
B12 Cobalamin Beef, pork, ham, poultry, lamb, fish, dairy, eggs

Table 2

Since vitamin B is water-soluble, side effects are less likely to occur with dietary consumption or with B complex supplements. However, excessive dosage of any component of the vitamin (much higher than the recommended daily allowance) can cause some harm.

  • Vitamin B1 or thiamine has no known side effects due to its rapid excretion by the body. Rarely, it can cause skin irritation or allergic reactions.
  • High doses of vitamin B3 or niacin may lead to vomiting, skin flush (warmness and blushing of the skin) or higher blood sugar levels. Severely high doses cause niacin toxicity, which can lead to serious malfunctions like hepatic (liver) failure or multiple organ dysfunction, which can be life-threatening. It must thus not be consumed without a physician's prescription.
  • High levels of vitamin B5 are associated with GIT disturbances like diarrhoea.
  • High doses of vitamin B6 can cause irritation to the skin, eyes or respiratory tract. Vitamin B8 is also known to cause irritation.
  • Vitamin B12, when administered in its synthetic form, has the potential to cause several side effects including diarrhoea, muscle pain or muscle cramps, fatigue, headache or dizziness. Injectable forms are related with more severe anaphylactic reactions like wheezing, itching, difficulty swallowing, rapid heartbeat or development of rash.
Dr. Dhanamjaya D

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Medicines / Products that contain Vitamin B Complex


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