Health
The hidden dangers of supplements
With reports of vitamin toxicity on the rise in Australia, it pays to check your supplement labels to ensure you aren’t putting your health at risk.
By Sabrina Rogers-Anderson
When Katerina started experiencing numbness and tingling in her extremities in 2019, she didn’t think too much of it. After successfully battling melanoma a decade earlier, she’d doubled down on her healthy lifestyle – which included daily ocean swimming, a wholefood diet and no alcohol – and had never felt better.
But as a variety of strange symptoms began to appear over the course of the next few years – including the sensation of electric shocks in her legs, dizziness and difficulty walking – she sought help from a variety of medical professionals. To her dismay, tests were inconclusive and doctors remained baffled.
“One day in July 2023, I’d had a hectic day and felt dizzy and had trouble walking before bed,” says Katerina, 51. “Then I woke up in the night feeling like I was having a heart attack or stroke. I had complete numbness on one side, pins and needles on the other side, and my heart rate was going up and down. My daughter called an ambulance and I was taken to hospital.”
After running a battery of tests, doctors still couldn’t figure out what was wrong with Katerina. She was misdiagnosed with a range of conditions – including benign paroxysmal positional vertigo (BPPV) and vestibular migraine – and her condition kept getting worse.
“I was bedridden and couldn’t look after myself,” she says. “I weighed 48 kilos and my muscles were wasting away. I thought I was dying and there was a point where I thought I might be better off dead. My partner and daughter had to be my carers 24/7 and I felt like such a burden to them.”
Hidden toxicity
It wasn’t until a GP decided to run a thorough series of blood tests that the truth was finally revealed. “My vitamin B6 levels were about 10 times the normal amount,” says Katerina. “I had been taking a magnesium supplement for years that had B6 in it and I’d developed B6 toxicity.”
While Katerina was lucky that a doctor had finally clued in to what was causing her symptoms, he mistakenly told her that she’d excrete all the excess vitamin B6 in her urine within a few weeks of stopping the supplements.
“I now know vitamin B6 can stay in your system for a long time,” explains Katerina. “I was desperate, so I found a Facebook group that had a good protocol to help me get rid of it. It’s nothing crazy – just hydration, electrolytes and exercise – but it’s really helped.
“I’m still not feeling 100% – probably 80% at this stage – but I can finally get on with my life. I’m back to exercising, writing my book and spending time with my family, and I couldn’t be more grateful.”
What is vitamin B6?
Vitamin B6 is naturally present in animal and plant foods including beef liver, salmon, tuna, poultry, chickpeas, dark leafy greens, bananas and fortified cereals.
It helps break down carbohydrates, proteins and fats, and plays an important role in supporting immune function and brain health.
More on this: Immune health and how the B-team of vitamins support ageing
In Australia, the recommended daily intake of vitamin B6 for adults is between 1.3 and 1.7mg depending on age and gender. Most people get enough B6 in their diets.
Why are cases of vitamin B6 toxicity on the rise?
With 47 percent of Australians using dietary supplements containing vitamins and minerals, it’s a booming business. But it may have the potential to do more harm than good.
“The public tends to believe that because vitamins are ‘natural’, they must be safe,” says Dr Ian Musgrave, a molecular pharmacologist and toxicologist at the University of Adelaide. “But if you take high enough doses, they will cause problems.
“Vitamin B6 is often added into workout supplements, magnesium supplements and other products. Too much B6 can cause peripheral neuropathy [nerve damage that causes numbness or tingling in the hands and feet] and other symptoms.”
While there tends to be more awareness that fat-soluble vitamins such as vitamin A – which are stored in the liver, fat and muscles – can be dangerous in high doses, water-soluble vitamins like B6 are often considered harmless because any excess is believed to be excreted in urine. Even medical professionals have fallen prey to vitamin B6 toxicity due to this widely held belief.
“The truth is that even water-soluble vitamins can have negative health effects if you take too much,” explains Dr Musgrave. “In the case of B6, relatively low concentrations can cause issues.”
How to protect yourself from vitamin B6 toxicity
In response to the escalating number of B6 toxicity cases, the Therapeutic Goods Administration (TGA) issued new labelling and use regulations in 2022.
They include:
- Products containing more than a 10mg daily dose of B6 require a warning about peripheral neuropathy.
- The maximum allowed daily dose of B6 in individual products has been reduced from 200mg to 100 mg for adults.
“The warning is there, but the question is: how effective is it?” questions Dr Musgrave. “The TGA has recently indicated it might tighten regulations and require products containing B6 to be sold behind the counter.”
To protect yourself from vitamin B6 toxicity, the TGA recommends that you:
- Check the labels of all your vitamins and supplements for vitamin B6 and its other chemical names, including pyridoxine hydrochloride, pyridoxal 5-phosphate and pyridoxal 5-phosphate monohydrate.
- Calculate the total amount of B6 you’re ingesting daily and consider keeping it below 50mg a day. While recommendations are for a maximum of 100mg a day, some people experience peripheral neuropathy even at low doses.
- Watch for signs of peripheral neuropathy, including numbness, tingling or burning in your hands and feet. If you experience any of these, stop taking your supplements and see a doctor.
What other ingredients in supplements may be dangerous?
Vitamin B6 is just the tip of the iceberg when it comes to potentially harmful ingredients in dietary supplements.
If you take several supplements, it’s worth adding up your total daily intake of each of the following ingredients to ensure you’re not exceeding the maximum daily dose.
Andrographis
Andrographis paniculata is a herb that’s commonly used in supplements designed to boost the immune system and relieve symptoms of the common cold. The TGA issued a warning in 2020 that these products, especially the brand Armaforce, may cause loss of taste. More severe reactions, including hives and anaphylaxis, have also been reported.
Vitamin A
Doses greater than 10,000 IU/day can lead to toxicity over time with symptoms including skin peeling, vision loss and liver damage. High doses of vitamin A can also cause birth defects in pregnant women.
Vitamin B3 (niacin)
Taking 500mg/day or more can lead to skin flushing and burning and low blood pressure. High doses of 3mg/day can lead to blurred vision, vision loss, and loss of eyelashes and eyebrows.
Vitamin C
Too much vitamin C can lead to nausea, abdominal cramps, headaches and kidney stones. Vitamin C can also interfere with several medications and medical tests.
Vitamin D
Doses of 4000–10,000 IU/day can reduce bone density and very high doses may lead to seizure, coma and even death.
Vitamin E
Alpha-tocopherol, a type of vitamin E, may lead to an increased risk of hemorrhagic stroke. Taking 400 IU or more of vitamin E for more than a year has been linked to early death.
Minerals
High doses of calcium, magnesium, zinc, selenium, iron and folic acid can lead to toxicity and a range of adverse effects.
Fish oil
More than 3g a day may decrease blood clotting.
Check your supplement labels
The average Australian doesn’t need to take supplements because they get enough vitamins and minerals in their diet. If you’re concerned that you may be taking excessive doses of a vitamin or mineral or you have any worrisome symptoms, talk to your GP.
Feature image: iStock/elenaleonova
This article is general information only and is not medical advice. It should not be used to diagnose or treat a health problem or disease. Do not use the information found on this page as a substitute for professional medical or health advice. Any information or links on this page should be verified with your professional health care provider.
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