What Is the Function of Vitamin B Within the Human Body?

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Vitamin B is a family of eight different vitamins that help drive processes your body uses for getting or making energy from the food you eat. Vitamin B has various functions in the human body because you need energy for all of your basic growth and life-sustaining processes. Vitamin B deficiencies can cause problems such as tiredness, abdominal pain and numbness. Depression, anemia and respiratory infections can also result from vitamin B deficiencies.


A variety of your body's metabolic functions depend on B vitamins. Individual B vitamins serve as catalysts, which drive chemical reactions that occur when you metabolize various nutrients. Vitamin B-7 catalyzes steps that are necessary for metabolizing cholesterol, fatty acids and amino acids. Vitamin B-9 and B-6 also drive chemical reactions that metabolize amino acids, which are the building blocks of proteins in your body. Metabolizing drugs and toxins in your liver depends on vitamin B-5. Your metabolic system uses vitamin B-2 for processing carbohydrates, fats, proteins, iron and other B vitamins. Your body needs vitamin B-1 for producing energy from food, and metabolizing glucose, which is your body's primary fuel substance.


Muscle Tone

The B vitamins help your body maintain muscle tone and adapt to exercise due to their critical energy production roles. Your muscles store glucose as glycogen for energy. During strenuous exercise, vitamin B-6 speeds up the release of glucose from glycogen in your muscles. Vitamin B-5 deficiency is rare in humans but reduces glycogen storage and exercise tolerance in rats. According to Nutritionist Kelly Dorfman, increasing vitamin B intake may help speed up skeletal muscle formation in children that have low muscle tone associated with developmental delays.


Nervous and Immune System

Vitamin B supports healthy immune and nervous systems. Your body needs vitamins B-5 and B-12 to protect your nerve cells and make fatty acids that maintain nerve cell functioning. Vitamins B-12 and B-6 are both essential for making neurotransmitters, such as serotonin, dopamine and norepinephrine. Vitamin B-1 deficiencies are associated with nervous system problems, such as exaggerated reflexes, numbness, tenderness and seizures. The B vitamins also support a healthy immune system.

Cell Growth and Division

Cell growth and division in your body depends on B vitamins. You need vitamin B-9 to make DNA, which is in all of your body's cells. Vitamins B-5 and B-7 are important for cell division and copying DNA information into new cells. Vitamin B-6 is particularly important for the formation of red blood cells, which transport oxygen to all your tissues and organs. Vitamin B-6 helps your body produce hemoglobin, which is a component of red blood cells that affects their ability to pick up and release oxygen.