Health Benefits of Vitamin B6

Uses, Safety, Side Effects, and Drug Interactions

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Vitamin B6, also known as pyridoxine, is part of a group of B vitamins that serve as "helper molecules" in effecting a number of key biochemical processes. These include the metabolism of nutrients and the synthesis of hemoglobin (which transports oxygen in the blood), antibodies (which support the immune systems), and neurotransmitters (which deliver nerve signals).

If we don't get enough vitamin B6, our bodies will be less able to process the fats, carbohydrates, and proteins we eat, while key functions of the circulatory, immune, and nervous systems will begin to break down.

Vitamin B6 is found naturally in the foods we eat but is also available in supplement form. In most cases, you can get all that you need from food. If you are deficient, vitamin B6 supplements may be recommended. Doses would vary based on your age, sex, and health condition.

Health Benefits

Vitamin B6 supplements are commonly prescribed to treat or prevent certain health conditions. The aim of treatment is to restore your body's metabolic function in the face of disease, dietary deficiencies, aging, hormonal imbalances, immune system breakdowns, or treatment side effects.

According to the National Institutes of Health, vitamin B supplements may be useful in treating the following conditions:

By contrast, many conditions believed to benefit from vitamin B6 supplementation have proven ineffective in clinical research. These include acne, Alzheimer's disease, asthma, attention deficit-hyperactivity disorder (ADHD), autism, cataracts, carpal tunnel syndrome, heart disease, depression, and osteoporosis.

Similarly, while vitamin B6 is frequently touted for its memory-enhancing benefits, there has been no clinical evidence of this in research.

Presumed Health Benefits

Vitamin B6 is known to benefit cardiovascular health, mainly be lowering a byproduct of metabolism known as homocysteine which is associated with an increased risk of atherosclerosis. With that being said, supplementation with vitamin B6 has not been shown to prevent death or heart attack in people with heart disease. The one exception may be with stroke.

A 2015 review of studies published in the journal PLoS One concluded that vitamin B6 and folic acid were the two B vitamins strongly associated with a reduction in stroke risk.

Other studies have been contradictory. As opposed to the dietary intake of B vitamins, the daily supplementation with vitamin B6, folic acid, and other B vitamins did nothing to reduce the risk of stroke, heart attack, or cardiac death, according to 2014 research published in PLoS One.

Similar results were seen with cancer. While research has consistently shown that eating foods rich in vitamin B6 are associated with a lower risk of all cancers (particularly gastrointestinal cancers), the same may not apply to vitamin B6 supplements.

According to a 2017 review of studies published in the Journal of the National Cancer Research, when taking into account diet and supplementation, the protective benefit of vitamin B6 with cancer considered weak to nil.

Possible Side Effects

Vitamin B6 supplements are considered safe when used appropriately. If taken above the daily RDA, side effects can include nausea, vomiting, diarrhea, stomach pain, loss of appetite, headache, tingling skin, and sleepiness. Extremely high doses may cause ataxia (involuntary muscle movements), numbness, painful skin lesions, and light sensitivity.

Vitamin B6 should not be used in people with diabetes who have had a recent stroke. Doing so may increase the risk of cancer, according to a 2012 study in the journal Stroke.

Vitamin B6 can also interact with certain medications. Advise your doctor if you intend to take vitamin B6 and are on any of the following drugs:

  • Cordarone (amiodarone)
  • Dilantin (phenytoin)
  • High blood pressure medications
  • Levodopa
  • Luminal (phenobarbital)

Vitamin B6 can break down many of these drugs and make them less effective. When taken with Cordarone, vitamin B6 may increase your sensitivity to sunlight and the risk of sunburn, rash, and blistering.

Dosage and Preparation

The National Academy of Science is tasked with issuing the recommended dietary intake (RDA) of nutrients in the United States. The daily RDAs for vitamin B6, either by food or a combination of food and supplements, are:

  • Infants 0-6 months: 0.1 mg
  • Infants 7-12 months: 0.3 mg
  • Children 1-3 years: 0.5 mg
  • Children 4-8 years: 0.6 mg
  • Children 9-13 years: 1 mg
  • Males 14-50 years: 1.3 mg
  • Males over 50 years: 1.7 mg
  • Females 14-18 years: 1.2 mg
  • Females 19-50 years: 1.3 to 1.7 mg
  • Females over 50 years: 1.5 mg
  • Pregnant women: 1.9 mg
  • Breastfeeding women: 2 mg

If used to help treat a specific medical treament, higher dosages may be needed. Among the current treatment recommendations:

  • Age-related macular degeneration: Combine 50 mg of vitamin B6 with 1,000 micrograms (mcg) of vitamin B12 and between 1,000 and 2,500 mcg of folic acid.
  • Atherosclerosis: A single-pill supplement (marketed under the brand names Kyolic, Total Heart Health, and others) is typically prescribed. Each pill contains 12.5 mg of vitamin B6, 100 mcg of vitamin B12, 300 mcg of folic acid, 100 mg of L-arginine, and 250 mg of aged garlic extract.
  • Kidney stones (adults): Between 25 to 500 mg of vitamin B6 daily is recommended.
  • Kidney stones (children): Up to 20 mg/kg daily may be given to children 5 and over.
  • Morning sickness: Between 10 and 25 mg of vitamin B6 taken three or four times daily usually helps. Other single-pill options containing vitamin B6 are available.
  • Premenstrual syndrome (PMS): Between 50 and 100 mg of vitamin B6 is used daily, with or without 200 mg of magnesium.
  • Pyridoxine-dependent seizures: An injection of between 10 and 100 mg is recommended during a seizure episode in infants.
  • Sideroblastic anemia: Start with an oral dose of 200 to 600 milligrams (mg) of vitamin B6 per day, then reduce to 30 to 50 mg per day once the red blood count has normalized. If injections are prescribed, start with 250 mg of vitamin B6 daily and reduced 250 mg once weekly.
  • Tardive dyskinesia: Between 100 to 400 mg of vitamin B6 per day may provide relief. Doses may be divided into 12-hourly doses to maintain a steady-state concentration of vitamin B6 in the blood.
  • Vitamin B6 deficiency: Start with 2.5 to 25 mg daily for three weeks, then decrease to 1.5 to 2.5 mg per day thereafter. In women taking birth control pills, the dose is 25 to 30 mg per day.

What to Look For

Vitamin B6 supplements can be found in most any drugstore, grocery store, or health food store. While commonly purchased in pill form, they are also available as an effervescent, liquid, chewable, and gummy supplement. Vitamin B6 is also included in multivitamin and B complex formulations. Check the product label to identify the daily value (DV) each tablet supplies.

To ensure safety and quality assurance, only purchase supplements given the stamp of approval by an independent, third-party certifying body like the U.S. Pharmacopeia (USP), NSF International, or ConsumerLab.

Vitamin B6 (pyridoxine HCL) injection is available by prescription and must be administered by a qualified medical professional.

Other Questions

Without question, the best source of vitamin B6 is food. It is important, therefore, to ask yourself if you actually need a vitamin supplement. If you're in good heath and eat a well-balanced diet, you probably don't.

To meet your RDA for vitamin B6, include the following foods in your diet:

  • Fortified cereal (2 mg per 3/4-cup serving)
  • Baked potato with skin (0.7 mg per medium-sized potato)
  • Banana (0.68 mg per medium-sized fruit)
  • Garbanzo beans (0.57 mg per 1/2-cup serving)
  • Chicken breast (0.52 mg per half-breast)
  • Rainbow trout (0.29 mg per 3-ounce serving)
  • Sunflower seeds (0.23 mg per ounce)
  • Avocado (0.2 mg per 1/2-cup serving)
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