Takeaway
Vitamin B6 toxicity is often overlooked, especially when patients present with cardiac or neurological symptoms. When diagnoses remain elusive, ask about supplement usage and energy drink consumption.
Lifelong Learning in Clinical Excellence | November 4, 2024 | 2 min read
By Ashli Greenwald, MS, RDN, LDN, Johns Hopkins Medicine
“I thought I was having a stroke” my patient, Ms. J, said when I met with her for a two-year postop bariatric surgery visit. She was 15 weeks pregnant and had successfully lost >25% of her total body weight. Ms. J had been taking her bariatric vitamins and calcium citrate as directed since surgery. She’d recently added a vitamin B6 supplement which she Googled and learned it can help with pregnancy induced nausea and vomiting.
Ms. J described a situation that happened a month ago where she experienced shortness of breath with both rest and exertion, chest tightness, palpitations, and numbness to the left side of her body. These symptoms took her to the ED. All tests came back with normal results, yet the symptoms continued.
During our appointment, she brought in all the vitamins and minerals she was taking. A standard post-op bariatric lab panel was obtained as well as a vitamin B6 level since she’d been taking this additional supplement for two months. Her B6 levels came back 52.2 ng/mL which was more than double the normal range.
The Recommended Daily Allowance (RDA) for vitamin B6 ranges between 1–2 mg/d depending on age, sex, and pregnancy/lactation status. In 2023, European Food Safety Authority (EFSA) released a scientific opinion on the tolerable upper intake levels for vitamin B6 and changed the the tolerated Upper Limit (UL) to 12 mg/day based on systematic reviews that examined associations between vitamin B6 and peripheral neuropathy. Ms. J was getting 12mg in her multivitamin plus an addition 100mg from her B6 supplement which was >5000% the RDA for a pregnant person. She was instructed to stop her extra vitamin B6 immediately and within a week there was a resolution of her symptoms.
Here are a few takeaways:
Vitamin B6 is a water-soluble vitamin that is important for the development and maintenance of the central nervous system, and for optimal brain functioning and metabolism. Good dietary sources of Vitamin B6 include poultry, fish, beans, and legumes, fruits and vegetables, and fortified grains. Toxicity due to dietary sources is rare, however with the use of supplements toxicities can be seen and often overlooked.
Vitamin B6 toxicity is more common than you may think. In addition to patients taking many OTC supplements for multiple reasons as marketed by the latest trends, many are drinking energy drinks or hydration products. Most energy drinks on the market contain anywhere from 1.7-3.4 mg of Vitamin B6 per serving. Many people are drinking more than one a day and putting themselves at risk for vitamin toxicity and not even realizing it.
This piece expresses the views solely of the author. It does not necessarily represent the views of any organization, including Johns Hopkins Medicine.