In recent weeks, reports have surfaced about severe reactions linked to over-the-counter vitamin B6 supplements. Excessive intake of this essential nutrient can lead to nerve damage, causing symptoms such as numbness, tingling, and even difficulty walking.
Surprisingly, some individuals experiencing these effects were unaware that their supplements even contained vitamin B6. So, what exactly is vitamin B6, how much do we need, and when does it become harmful?
Understanding Vitamin B6
Vitamin B6, also known as pyridoxine, is a group of six compounds with a similar chemical structure. It is an essential nutrient, meaning our bodies require it for various functions but cannot produce it naturally.
For adults aged 19–50, the recommended daily intake is 1.3 mg. This increases to 1.7 mg for men and 1.5 mg for women over 51, while pregnant and breastfeeding individuals need 1.9 mg.
The nutrient is primarily found in animal products such as meat, dairy, and eggs. However, plant-based sources like spinach, bananas, potatoes, and kale also provide sufficient amounts, making deficiency uncommon—even among vegetarians and vegans.
Before the body can use dietary vitamin B6, the liver converts it into pyridoxal-5′-phosphate (PLP), which plays a crucial role in more than 140 cellular functions. These include protein metabolism, red blood cell production, blood sugar regulation, and brain function.
Despite being readily available through food, vitamin B6 is commonly added to supplements, multivitamins, and energy drinks.
Is Vitamin B6 Toxicity a Concern?
Vitamin B6 toxicity is rare and unlikely to occur from food sources alone, except in cases where medical conditions hinder proper nutrient absorption (such as celiac disease). Since B vitamins are water-soluble, excess amounts are typically excreted in urine.
However, in some cases, excessive intake from supplements can lead to the accumulation of vitamin B6 in the blood, resulting in peripheral neuropathy—a condition that damages sensory nerves outside the brain and spinal cord. Symptoms include numbness, tingling, and, in severe cases, difficulty with balance and walking.
The exact mechanism behind this toxicity remains unclear, but researchers believe it interferes with neurotransmitter function, affecting nerve signaling. While symptoms often improve after stopping high-dose supplementation, they may not fully resolve.
How Much is Too Much?
Toxicity is usually linked to high-dose supplements rather than dietary intake.
Until 2022, products with more than 50 mg of vitamin B6 were required to display a warning about peripheral neuropathy. However, the Therapeutic Goods Administration (TGA) has since lowered this threshold to 10 mg, requiring any product exceeding this amount to carry a warning label.
Additionally, the TGA halved the daily upper limit of vitamin B6 in supplements from 200 mg to 100 mg after reviewing reports of 32 cases of peripheral neuropathy linked to supplements. Notably, two-thirds of these cases involved doses below 50 mg.
Are B Vitamins Always Beneficial?
While B vitamins are essential for overall health, excessive intake can have unintended consequences. The new regulations aim to minimize the risk of toxicity while increasing consumer awareness of B6-containing products.
Although vitamin B6 toxicity is uncommon, questions remain about why some individuals experience nerve damage even at lower doses. Possible explanations include differences in how specific B6 compounds affect the body or genetic predispositions that increase susceptibility.
What Should You Do?
For most people, a well-balanced diet provides sufficient vitamin B6 without the need for supplements.
However, many people unknowingly consume vitamin B6 through multivitamins and products labeled as magnesium or zinc supplements. To avoid excessive intake, always check ingredient labels when starting a new supplement, especially if it hasn’t been prescribed by a healthcare professional.
If you take multiple supplements, be mindful that their combined vitamin B6 content may exceed safe levels over time. Be particularly cautious if you experience symptoms like pins and needles, numbness, or pain in the hands or feet, as these could be early signs of peripheral neuropathy.
For personalized advice, consult your doctor, dietitian, or pharmacist before making changes to your supplement routine.