Vitamin B6 – What Is It?

Vitamin B6 structureThe generic name for vitamin B6 is pyridoxine.  Vitamin B6 is really a family of three compound groups and the active form of the vitamin is pyridoxal phosphate (PLP).  Vitamin B6 is absorbed in the middle and latter sections of the small intestine and converted in the liver into three forms, mainly PLP.  Not much of this vitamin is stored in the body, but what little is stored in the body is kept in the muscles.

What Does It Do?

Vitamin B6 becomes a co-enzyme in the body and is used in over 100 metabolic reactions.  This vitamin is involved in 5 broad categories of reactions:

1) protein, carbohydrate, and fat synthesis and breakdown,
2) the synthesis of neurotransmitters (which are important for nerve function),
3) the synthesis of histamine (which is involved in the allergic immune response),
4) hemoglobin synthesis and function (which carries oxygen to tissues and carbon dioxide to
the lungs),
5) gene expression (which involves which proteins are made in the body).

Included in the first category, vitamin B6 helps to convert the amino acid tryptophan into niacin (vitamin B3).  Remember back when we discussed protein a few weeks ago and I stated that 11 of the amino acids can be made by the body, but 9 cannot and are considered essential?  Vitamin B6 helps out in the synthesis of those 11 amino acids.  Without vitamin B6 in our diets, all 20 amino acids would be considered essential and would have to be eaten in our diets to provide enough amino acids for use in our bodies.  As you can see, vitamin B6 is a pretty important vitamin!

Where Can You Find It?

Vitamin B6 FoodsSince vitamin B6 is stored in muscle tissues, it can be found in meat, fish and poultry.  Most fruits and vegetables are not good sources of this vitamin.  The sources that do have a good supply of vitamin B6 include carrots, potatoes, spinach, bananas, acorn squash, Brewer’s yeast, watermelon and sunflower seeds.   Other sources include peanut butter, garbanzo beans, and ready-to-eat cereals.   Unfortunately, this vitamin is not stable when subjected to heat or alkaline (basic) conditions.  Heat and food manufacturer processing can reduce the amount of vitamin B6 in foods from 10-50%.

How Much Do You Need?

The RDA for vitamin B6 is shown below: 

Group

Recommended Daily Allowance

Infants and children
0-6 months

0.1   mg

7-12 months

0.3   mg

1-3 years

0.5   mg

4-8 years

0.6   mg

9-13 years

1.0   mg

Males:
14-50 years

1.3   mg

50+ years

1.7   mg

Females:
14-18 years

1.2   mg

19-50 years

1.3   mg

50+ years

1.5   mg

Pregnancy

1.9   mg

Lactation

2.0   mg

Tolerable Upper Limit

100   mg

What Happens If You Don’t Get Enough?

Seborrheic dermatitis

Seborrheic dermatitis

Given how many processes are affected by vitamin B6, it’s no surprise that there are deficiency diseases associated with this vitamin.  Symptoms associated with a deficiency of vitamin B6 include seborrheic dermatitis, microcytic hypochromic anemia, convulsions, depression, and confusion.  Seborrheic dermatitis is an inflammation of the sebaceous glands in skin and results in scaly, flaky, itchy, red skin.  Microcytic hypochromic anemia is a disease where red blood cells do not have enough hemoglobin, so there is reduced oxygen transport throughout the body.  It can also be caused by a deficiency of iron.

Deficiencies can also result from malnutrition in chronic alcoholism.  Deficiencies in vitamin B6 usually occur in association with other B-complex vitamins.

What Happens If You Take Too Much?

Even though this is a water-soluble vitamin, there is a Tolerable Upper Limit of 100 mg/day, which is based on the point where nerve damage can occur.  Taking high levels of vitamin B6 over two or more months can lead to irreversible nerve damage.  These symptoms start out as difficulty in walking and hand and foot numbness.

Vitamin B6 has been used in some medical therapies, such as carpal tunnel syndrome, depression and premenstrual syndrome (PMS).  However, the research supporting the benefits of these therapies has been inconclusive.  Vitamin B6 has been shown to reduce the risk of colorectal cancer.

As a note, the diseases that are listed above occur because of supplemental vitamin B6.  There have been no adverse effects of vitamin B6 over-consumption when the vitamin intake comes strictly from foods.

Bottom Line

The best way to consume any nutrient in order to avoid over- or under-consumption is to consume a wide variety of foods, in a wide variety of colors, and eat according to MyPlate.

Until next time, remember that… there are no excuses when it comes to your health!

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One thought on “Vitamin B6 – What Is It?

  1. Pingback: How to Avoid Having Seborrheic Dermatitis

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