I'm A Doctor ― Here's The 1 'Harmful' Supplement I'd Never Take

The NHS has advised all adults living in the UK to consider taking vitamin D supplements until March, because the lack of sunlight during the colder months means many of us risk becoming deficient. 

However, they also say that some common supplements do nothing whatsoever to prevent colds and flu. 

And now, UK GP Dr Ahmed has shared on TikTok “the only one supplement [he’d] never, ever take.” 

Though some supplements can be “very effective,” he adds, he warns against “this one supplement lots of people still take, despite studies showing it can increase your mortality rate.” 

What is it?

“Any multivitamin supplement” is off the cards for the doctor. 

Indeed a 2024 study published in JAMA Network Open found that those who took multivitamin tablets had a 4% higher risk of mortality than those who didn’t, though it didn’t prove the supplements were the cause ― it just found an association. 

There is a chance that this association was only found because multivitamin consumers were already worried about their health, for instance. Still, the study says, multivitamin supplements were “not associated with a mortality benefit.”

The problem which can lie with multivitamins, Dr Ahmed says, is that they often offer more than 100% of your vitamin needs a day. 

So if you’re taking them regularly, it “can be dangerous, in particular [with] things like vitamin A and vitamin K.” 

The NHS says: “Some research suggests that having more than an average of 1.5 mg (1,500 µg) a day of vitamin A over many years may affect your bones, making them more likely to fracture when you’re older.” 

They add, “You should be able to get all the vitamin K you need by eating a varied and balanced diet.

“If you take vitamin K supplements, do not take too much as this might be harmful.”

So how can I get enough vitamins and minerals?

“Assuming you have a normal, balanced diet, having 100% of these vitamins and minerals [on top of that] is not needed,” Dr Ahmed says.

“You’re far better off taking one vitamin or supplement for your needs” than simply grabbing a multivitamin off the shelf if you have concerns (a blood test can reveal any real, rather than presumed, deficiencies).

Speak to your doctor if you’re worried about your health.