vitamins are compounds that work either as cofactors in the cellular metabolism for energy production or act as precursors to the cofactors. Though they are structurally different, they are jointly known as Vitamin B complex. They are water soluble and usually exist together in the same food.  Though researchers have identified a number of roles of the individual B vitamins, they primarily work as bioenergetics. They are essential for most of the biochemical processes that break down the various constituents in foodstuffs such as sugar, amino acids and fatty acids into smaller molecules that are involved in the cellular respiration process. Some of these B vitamins transport electrons to the various constituents of cellular respiration, leading to the production of ATP, the major energy source of the body cells. All cellular functions are fueled by this cellular energy. Therefore, deficiencies in the B vitamins will disrupt the normal process of cellular energy production and affect the healthy cellular functions. 
Though the B vitamins comprise of a group of eight compounds, deficiency of any of these compounds will wreak havoc on your health. For instance deficiency of only niacin, a B vitamin, will stop production of NAD, a cofactor in anabolic reactions, thereby inhibiting activities of enzymes that convert glucose into energy. As all the body organs need energy to function, niacin deficiency affects your overall health. A severe deficiency leads to a pellagra that causes dermatitis, diarrhea and dementia and could be fatal if left untreated. Hence, your body is affected by the deficiency of any one B vitamin. As foods contain a mixture of various B vitamins, isolating deficiency of a single vitamin is quite difficult. Though diseases such as pellagra and beriberi are usually attributed to deficiency of single B vitamin, studies have shown people suffering from these health disorders are deficient in a number of B vitamins, of which, deficiency of one vitamin was found to be more pronounced. 
Compounds that are known as vitamin B-complex comprise of vitamin B1 or thiamine, vitamin B2 or riboflavin, vitamin B3 or niacin, vitamin B5 or pantothenic acid, vitamin B6 or pyridoxine, biotin or vitamin B7, folic acid or vitamin B9 and the cobalamins or vitamin B12. Apart from these essential vitamins, there are three non-essential vitamins, inositol, choline and para-aminobenzoic acid (PABA) that are sometimes considered part of the vitamin B-complex group. Each of these B vitamins is involved in diverse activities. Thiamine, riboflavin, niacin and biotin are primarily involved in energy production. Vitamin B6 is primarily needed for metabolism of amino acids. Folic acid and vitamin B12 are necessary for division of cells. In addition, each of these B vitamins is involved in other additional functions. However, in the cellular functions involving the B vitamins, all the B vitamins are not needed simultaneously. 
Benefits Of B Vitamins
The individual B vitamins and the combined effect of the different B vitamins benefit the health in various ways.
1. Helps In Metabolism For Energy Production
Your body needs the B vitamins for metabolism of carbohydrate, protein and fats for production of cellular energy. The metabolic reactions are regulated by enzymes and substances known as cofactors. The cofactors are essential for activating the enzymes involved in metabolism. They work either by combining with these enzymes or they create an environment that enables the enzymes to work. These cofactors are either inorganic ions that are known as activators such as copper, sodium, potassium and cobalt or organic compounds known as prosthetic groups or coenzymes that bind with the proteins in the enzyme.
The role of the B vitamins is to act as the operative part of these coenzymes for oxidation of carbohydrates, protein and fats, leading to energy production. Your body needs at least five types of B vitamins for releasing energy from glucose.  However, this does not mean that you will experience a surge in energy simply by taking vitamin B-complex supplements. You get the calories from carbohydrate, protein and fats. The higher your demand for calories, the higher is the demand for the B vitamins to break down the calorie containing foods for energy production. Therefore, athletes or physically active individuals who burn more calories than people who lead a sedentary life need more B vitamins. 
2. Maintaining Brain Health
Though the brain comprises only 2% of the body weight, it is responsible for more than 20% of the total energy expenditure of the body. As the B vitamins are essential for energy production, they play an important role in maintaining the healthy functioning of the body’s most metabolically active organ. Studies have revealed that the concentrations of the various B vitamins, especially folate, biotin and pantothenic acid are significantly high in the brain than in the plasma.
Furthermore, the B vitamins are needed for the synthesis of a number neurochemicals and signaling molecules. They are also needed for the production and repair of DNA and RNA and normal methylation reactions. Moreover, by lowering the level of homocysteine, a potentially toxic amino acid associated with cognitive impairment, dementia and Alzheimer’s disease, the B vitamins, especially, folate and vitamins B6 and B12 help in maintaining the healthy brain function. 
3. Helps Fight Stress And Improves Mood
Psychological problems are often considered as the initial symptoms of deficiency of B vitamins. Anger, irritation and difficulty in coping with stress at workplace or home could occur if you are deficient in these important B vitamins. Ingesting vitamin B-complex supplement containing 10mg of vitamin B1 and relative amounts of other B vitamins is known to fight stress and improve mood. If the given dosage of B vitamins fails to produce the desired result within thirty days, tripling the doses or taking a B-complex supplement containing 25mg of vitamin B1 may help in alleviating stress.
A study has revealed that regular intake of B-complex supplement containing 10 times the recommended dietary allowance (RDA) of all the B vitamins for a year helps in improving mood. Though all the B vitamins were found to help in improving mood, vitamin B1 was especially found to be effective and worked in a short time. Folic acid was also found to help in reducing depression. Research has found elderly patients with depression usually suffered from folic acid deficiency. 
4. Production Of Healthy Blood Cells
The immature blood cells need the B vitamins folate and vitamin B12 to grow and develop into mature red blood cells. The B vitamins enable the precursor cells to replicate the DNA and divide rapidly to form the healthy red blood cells. As the red blood cells are among the rapidly dividing body cells, they are easily damaged by deficiencies of folate and vitamin B12. Deficiencies of these B vitamins lead to formation of abnormal red blood cells that are fragile, larger than the normal red blood cells and have a shorter life span. It causes a type of anemia known as megaloblastic anemia. Folate is also essential for the production of white blood cells that regulate the body’s immunity. 
5. Healthy Pregnancy
B vitamins are essential for minimizing risk of birth defects and help in healthy development of the baby. Pregnant women are therefore advised to add foods rich in B vitamins to their daily diet. Good quality prenatal vitamins or vitamin B-complex supplements are also known to help in development of the baby and are capable of reducing some of the complications associated with pregnancy. All the B vitamins are known to keep a woman strong and healthy throughout pregnancy especially during the first and third trimesters when most women tend to feel more exhausted. Vitamin B1 aids proper development of the brain of the baby. The development of the baby’s eyes, skin, bones, nerves and muscles is regulated by vitamin B2. It is also known to reduce the risk of preeclampsia in pregnant women.
Niacin is known to reduce nausea and migraine and helps improve digestion during pregnancy. It also plays a role in development of the baby’s brain, nervous system, skin and mucous membrane. Vitamin B5 supports production of important hormones during pregnancy and helps in reducing leg cramps. Apart from helping in the development of the baby’s brain and nervous system, vitamin B6 helps in reducing pregnancy related nausea and vomiting and aids synthesis of important neurotransmitters. Folic acid is one of the most important nutrients for pregnant women. Deficiency of folic acid causes neural tube defect in babies. Vitamin B12 is also known to reduce risks of neural tube defect and other defects of the nerves. 
6. Helps Fight Cardiovascular Diseases
Studies suggest that the B vitamins, especially vitamins B6 and folate help in reducing death related to cardiovascular diseases. The beneficial effect of the B vitamins is primarily attributed to their ability to lower the homocysteine level in the blood. Both diet and the genes can help in elevating the homocysteine level in the blood. High homocysteine level is known to increase the risk of formation of life-threatening blood clots and it damages the inner lining of the blood vessels. In women, increased intake of folate and vitamin B6 helps in lowering the risk of heart problems and stroke and, in men it lowers risk of heart failure. 
7. Healthy Skin
B vitamins are essential for production of energy needed for the growth and development of the skin cells. To maintain the youthful appearance of the skin, the dermis, the lower layer of the skin, should continue producing sufficient new cells. The B vitamins ensure that the skin cells can divide and grow.  The B vitamin biotin is especially important for maintaining the skin health. Deficiency of this B vitamin is known to make the skin dry, scaly and itchy. 
Recent studies have revealed the effectiveness of topical application of certain B vitamins in fighting skin disorders. Niacin when applied to the skin in the form of its physiologically active form Nicotinamide helps in reducing acne vulgaris, necrobiosis lipoidica, dermatitis herpetiformis and bullous pemphigoid. Nicotinamide seems to work by modifying the inflammatory process that produces these skin disorders. Vitamin B12 combined with folic acid was found to help vitiligo. 
8. Good For Hair
By supporting protein metabolism and assisting in growth and repair of the cells, B vitamins help in maintaining the hair growth process. B vitamins are known to work together in fighting hair loss, loss of hair pigment and thinning of hair. Deficiency of B vitamins makes the scalp dry and causes excessive dandruff. Folic acid and vitamins B6 and B12, by supporting healthy development of the red blood cells that transport oxygen to the tissues, aid hair health. However, the B vitamin that is considered most important for the health of the scalp and the hair is biotin. Deficiency of biotin causes hair loss and dermatitis.  Also known as Vitamin H, biotin is known to maintain the texture, strength and the function of the hair. Loss of hair could also be a sign of folic acid deficiency. 
How To Get More B Vitamins In Diet
The best way to meet your body’s demand for the B vitamins is to eat a variety of organic whole foods that contain most of these vitamins. Some of the best natural sources of the B-complex vitamins are brewer’s yeast, blackstrap molasses, whole grains, wheat germ, brown rice, seeds and nuts. 
Brewer’s yeast is a rich source of the B vitamins and can be taken with juices, shakes and drinks and can even be sprinkled on popcorns and can be mixed with baked dishes, soups, spreads and other dishes. However, it is not recommended for people suffering from yeast infection or gout. You may experience bloating or flatulence when you introduce brewer’s yeast for the first time to your diet. These symptoms can be averted by gradually increasing intake of brewer’s yeast. Initially take less than one teaspoon per day and gradually increase the amount. 
Whole grains are rich in B vitamins. However, on average 66 percent of these important nutrients are lost when the whole grains are refined. Therefore, to increase the content of B vitamins in your diet, replace refined grains in your diet with whole grains such as brown rice, whole wheat, whole rye, buckwheat, oat, millet, amaranth, unhulled barley, cracked wheat, quinoa, wild rice and popcorn. 
Meat contains significant amount of B vitamins such as vitamins B1, B2, B3, B5, B6 and B12. The concentration of these vitamins is significantly higher in lean meat than in meat fat. As these vitamins are water soluble, the juices released from meat when it is cooked should be preserved and consumed with the meat dish. Some of these vitamins are lost when meat is cooked at high temperature for a long time. 
B vitamins are primarily found in the egg white. It is especially rich in vitamin B12 and provides 25 percent of the recommended dietary Intake (RDI). In addition, egg is a good source of riboflavin, biotin, folate and pantothenic acid. 
Cow’s milk is a natural source of all the eight B vitamins and is especially rich in vitamin B12, folate, riboflavin and pantothenic acid. The high bioavailability of the B vitamins ensures that your body can easily absorb these nutrients from milk.  Though milk, egg and meat are rich sources of all the B vitamins, organ meat such as kidney and liver are considered the best sources of the B-complex vitamins. 
Deficiency of folic acid can be averted by including green leafy vegetables in the daily diet. There are few good sources of folic acid. Although it is found in most vegetables, its content in green leafy vegetables such as spinach and watercress is the highest. Other green vegetables that are good sources of folic acid are cauliflower, broccoli and lady’s finger. 
You should get all the B vitamins in the right quantities according to the government dietary recommendations from your daily diet. The average daily requirement of thiamin is 1 mg for men and 0.8 mg for women. Men need 1.3 mg of riboflavin per day and women need 1.1 mg of the B vitamin daily. For men, the daily niacin requirement is 16.5 mg and for women 13.2 mg. The daily vitamin B6 requirement for men is 1.4 mg and 1.2 mg for women. For adults, 200 mcg of folic acid is needed on a daily basis. However, pregnant women may need up to 400 mcg of folic acid per day. The daily vitamin B12 requirement for adults is 1.5 mcg.  Making healthy food choices and eating well-balanced meals can easily meet your body’s requirement of the B vitamins.