Vitamin users have been urged to stop making a huge “mistake” when taking supplements. Rojina Shams Nateri, pharmacist at Roseway Labs, said there’s vital information they need to know
Katie-Ann Gupwell Acting Content Editor
09:08, 01 Mar 2026
Vitamin users have been urged to stop making the “error” (stock image)(Image: Guido Mieth via Getty Images)
Thousands of individuals consume supplements, with many claiming they can enhance overall wellbeing alongside sleep quality. Nevertheless, if you routinely take vitamins, attention is required, as a significant error could be occurring.
It often seems that, wherever we turn, people are recommending additional supplements for their benefits to hair, skin and bone health. Whilst they may support wellness in various respects, there are also crucial considerations regarding their use, and Rojina Shams Nateri, pharmacist at Roseway Labs, has cautioned that supplements can occasionally cause more damage than benefit.
She recently offered professional guidance to inform people of precisely what requires consideration. Indeed, an expert previously told people to stop taking vitamin D if they experience certain symptoms.
“One of the most common mistakes I see is stacking winter supplements that contain the same ingredients,” said Rojina. “You might take a multivitamin, an immune blend and extra zinc or vitamin C, and suddenly you’ve tripled your intake without meaning to.”
Numerous products feature zinc, vitamin C and B vitamins. Combined, they can propel consumption considerably beyond the recommended nutrient reference value (NRV), resulting in many individuals unknowingly overdosing on vitamins they assume are safe.
Presuming elevated doses are safe represents a particularly prevalent error. “People think vitamins are risk-free because you can buy them over the counter. That’s not true,” Rojina explained.
Zinc exceeding 9.5mg daily for men and 7mg for women can genuinely compromise immunity over time by disrupting copper uptake. Vitamin D beyond 100 micrograms (4,000 IU) may elevate calcium to hazardous concentrations.
Vitamin A accumulates within the body, though quantities surpassing 1.5mg (1,500mcg) risk liver damage and expectant mothers must completely avoid elevated doses. Even vitamin C has boundaries.
She continued: “The UK recommended intake is 40mg per day, and absorption becomes less efficient at higher doses. Once intake reaches anything above 200mg a day, excess vitamin C is largely excreted by the body.”
Potentially the most serious concern with supplements involves their interaction with medications. “Calcium, magnesium, iron and high-dose vitamin C can reduce the absorption of antibiotics, thyroid medication and some blood pressure drugs,” Rojina cautioned.
“If you’re taking prescription medicine, even short-term, always check before adding supplements.”
What’s worthwhile taking?
“In winter, vitamin D is sensible for most adults,” she noted. “Omega-3 with EPA and DHA supports brain and heart health. Magnesium can help with sleep and muscle tension.
“Supplements should support your health, not replace good sleep, balanced meals and medical advice. If you’re unsure, ask your pharmacist. It could save you from doing more harm than good.”
What many don’t realise is that consuming excessive vitamins can prove harmful, as it has the potential to result in toxicity, organ damage and other health complications. Whilst small quantities are vital, excessive amounts, particularly of fat-soluble vitamins (A, D, E, K), accumulate in the body instead of being eliminated, which can trigger adverse side effects.
Additionally, routinely consuming multiple supplements, or fortified foods (cereals, bars) together with tablets, can result in overdosing. This is precisely why vigilance is necessary.
Always seek medical advice before commencing supplements, particularly if you are pregnant, elderly or have any existing health conditions. Professional guidance should always be obtained first.
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