Vitamins are compounds needed by your body, but that cannot be produced by your body. As a result, you have to consume most vitamins as part of your diet in order for your body to function properly. Certain health conditions, diets and environmental factors may require you to take vitamin supplements to avoid a deficiency. Consult your doctor before taking health supplements such as vitamins and closely follow recommended guidelines for intake. Overdosing on vitamins, especially vitamin B6, may cause serious side effects, including damage to the brain and nervous system.
Vitamin B6
Vitamin B6 belongs to the B-complex of vitamins. You should be particularly careful about overdosing on vitamin B6, because B6 toxicity can cause damage to the brain and nervous system, a condition known as sensory neuropathy. The tolerable upper intake level for vitamin B6 set by the Institute of Medicine is 100 mg per day, and doses of 500 mg or more per day greatly increase the risk of nerve damage, according to the Linus Pauling Institute at Oregon State University.
Vitamin B6 Toxicity Symptoms
Symptoms of neuropathy usually begin as a sensation of numbness, burning or tingling in the hands and feet. As the damage worsens, the numbness or tingling often spreads up the arms and legs. Left untreated, vitamin B6-induced neuropathy can lead to difficultly walking, loss of balance and loss of coordination. The damage caused by vitamin B6 toxicity can be reversed if intake of vitamin B6 is stopped, and the symptoms often disappear within six months of the last intake.
Fat-soluble Vitamins
While vitamin B6 is the only vitamin reported to cause brain damage, other vitamin can result in other serious side effects. The fat-soluble vitamins, including vitamins A, D, E and K, are generally more likely to cause toxicity symptoms, because excess amounts of these vitamins accumulate in the fat tissues of the body. Overconsumption of vitamins A and D, in particular, can cause severe health problems, including growth retardation, kidney and liver damage, heart disease and bone pain. They may also cause less severe side effects such as nausea and other gastrointestinal disorders, reports Colorado State University.
Water-soluble Vitamins
The water-soluble vitamins include vitamin C and the B-complex vitamins. With the exception of vitamin B6, water-soluble vitamins are generally less likely to cause severe side effects, because excess amounts of these vitamins are usually flushed out of the body in urine. Many of the B-complex vitamins have not been reported to cause any serious toxicity effects. Large doses of vitamin C and vitamin B3 can cause gastrointestinal problems, including nausea and diarrhea.
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