Unveiling the Risks of Excessive Vitamin B6 Supplementation; The Impact on Nerve Health including Peripheral Neuropathy

Vitamin B6 is in the news at the moment!

Vitamin B6 is having 15 minutes of fame (or infamy!) due to a number of reported adverse effects, including peripheral neuropathy. This lack of sensation, tingling or numbness in the hands and feet is from nerve damage and can lead to weakness and difficulty walking, and could be irreversible!

Why are these adverse effects to B6 occurring?

B6, also known as pyridoxine or Pyridoxine-5'-Phosphate (P5P) when converted to its active form in the liver is absolutely a very beneficial supplement used most commonly for treating premenstrual syndrome (PMS), dysmenorrhea, vitamin B6 deficiency, pregnancy-induced nausea and vomiting, and depression. It is also used orally for primary homocystinuria, (high serum homocysteine), boosting immunity,  preventing kidney stones, preventing osteoporotic fractures, carpal tunnel syndrome, night leg cramps, insomnia, improving dream recall, arthritis, eczema and allergies. 

As a result, is  very common in multi vitamin supplements, protein powders, energy drinks, fortified foods such as cereals, and naturally in foods such as grains, legumes, vegetables, liver, meat, and eggs 

Even high doses may be used therapeutically but under medical supervision, and only short term!

However not all multivitamins are in the safe range!

Not only can B6 toxicity occur from the long term culmination of many sources, but some over the counter (OTC) multivitamins still contain levels far above the safe dose!  The recommended daily dose for Australia  and New Zealand is 1.3-1.7mg/day depending on your age, gender and activity level, with an upper level of about 50mg. While the Therapeutic Goods Administration (TGA) has strengthened labeling requirements and requires warnings on products with daily doses above 10mg of vitamin B6, concerns remain about underreporting of problems and the need for broader awareness.

Who is at risk of B6 toxicity?

While B6 is a very useful supplement I use in clinic regularly, particularly for improving mood and brain function, anyone who takes a multivitamin could potentially be at risk, which is why a practitioner should always ask about not only medications a client takes, but supplements as well!

Pregnant women should be diligent about B6 levels, as high doses in pregnancy can cause rebound seizures in newborns 

High doses of vitamin B6 supplements may increase the risk of lung cancer in smokers, particularly in men. Studies have found that smokers who took more than 20 mg of B6 daily were several times more likely to develop lung cancer compared to those who did not take B6 supplements. This is because B6 metabolism can produce harmful forms of the vitamin, especially in the presence of inflammation, which can be exacerbated by smoking.

An important consideration is that the risk is more likely associated with long-term, high-dose supplementation and not necessarily from consuming B6-rich foods. 

So here's 3 important take aways:

1. Always tell your practitioner of not only medications you take but supplements as well, including protein powders. It is preferable to have a list ready before your consultation, and a screenshot of the bottles can be very useful.  

2. It is best, where possible, not to self prescribe over the counter vitamins and minerals, even B vitamins that are water soluble can have adverse effects if you cannot metabolise them due to genetic or epigenetic factors. Although B6 is the focus here, niacin and activated folate (also B vitamins) will often cause issues in compromised individuals as well. 

   Be aware that minerals all compete!  For example, calcium is a strong inhibitor of iron absorption, and excessive zinc can interfere with the absorption of iron and copper. For this reason it is best to take zinc for no longer than six weeks, or as directed by your medical practitioner

3.  The signs and symptoms of a vitamin toxicity or deficiency may mimic many other conditions, see your doctor immediately if you ever experience peripheral neuropathy, remember, test don't guess! 

Would you benefit from a discussion about your supplements with a degree qualified Certified Practicing Nutritionist (CPN)?

Supplements are not only expensive but could be doing more harm than good if you are taking the wrong form and/ or combination. Book on my website www.bespokenutrition.com.au for a free discovery call to discuss a consultation to ensure your supplements are working best for you. Please note this is not medical advice and you should always follow the advice of your medical practitioner!