Vitamin B6 is part of the group of vitamins known as vitamin B complex. Vitamin B is essential to many bodily functions including amino acid metabolism. It’s also needed for the chemical reactions in the body that control the release of glucose to stabilizing your blood sugar levels.

Vitamin B6 was discovered by a physician from Hungary named Paul Gyorgy. He discovered vitamin B6 while attempting to cure rats of dermatitis. In the late 1930s, scientist Samuel Lepkovsky was able to isolate vitamin B6 extracted from rice bran. It was later determined that vitamin B6 was a precursor to pyridoxal 5-phosphate which is essential to a wide variety of enzymes on the body.

The metabolic form of vitamin B6, known as pyridoxal phosphate, is involved in many other bodily functions as well including macronutrient metabolism, neurotransmitter synthesis and gene expression. Vitamin B6 is metabolized in the liver where it becomes pyridoxal phosphate. The main role of vitamin B6 in the body is to be a coenzyme to many other different enzymes that are involved primarily in metabolic functions. The active form of vitamin B6, pyridoxal phosphate, is converted into two other forms found in some foods which are pyridoxine and pyridoxamine.

You can find vitamin B6 in many different foods including meat products, whole grains, nuts, vegetables and even bananas. You can lose up to 50% of the vitamin B6 content found in a food by cooking it. Canning and freezing food can also cause a reduction in B6 levels found in food. Plants contain a more stable version of vitamin B6 which is much less susceptible to heat and freezing. Vitamin B6 is mostly found in the outer layer of grains, making whole grain foods a much better source of B6 than foods made with white flour.

It’s important to get enough vitamin B6 in your diet as a deficiency is known to cause a wide range of illnesses including dermatitis, ulcers, conjunctivitis and some neurological conditions such as somnolence, confusion and even neuropathy. The side effects of a B6 deficiency are many dermatologic (on your skin) and neurologic (in your mind). Less severe cases of B6 deficiency can cause lesions due the lack of coenzyme needed to perform metabolic functions in the body. Vitamin B6 also plays an important role in glucogenesis, which makes a deficiency impair your overall glucose tolerance, which can be devastating to anyone with diabetes.

Overdose of vitamin B6 has only ever been found in people taking it as a dietary supplement. No one has ever overdosed on B6 found in food. Overdosing on vitamin B6 regularly can cause substantial neurological problems which may be irreversible. This is caused by damage to the dorsal root ganglia, which is a nodule that contains neurons in spinal nerves.

Symptoms of B6 overdose include numbness and in extreme cases, difficulty walking. Typically, neurologic damage is done when daily dosage of vitamin B6 exceeds 1,000 milligrams per day for an extended period of time, though there are some cases in which people have experienced neurologic damage after taking only 500 milligrams or less per day over a span of just a few months. No neurological damage has ever been reported in people taking 200 mg or less per day. Symptoms will usually cease after supplementation has been discontinued.

The FDA recommends no more than 100 milligrams of vitamin B6 to be taken daily as a supplement for adults. Other countries recommend just 50 milligrams of B6 per day as a maximum. These recommendations also apply to nursing or pregnant women as there is no evidence these levels of B6 cause any birth defects or complications.