The supplements that are and aren’t worth taking, according to a nutritionist

There are countless supplements available in pharmacies, supermarkets and health stores today – but how do you know they're right for you? Photo / Getty Images

In 2024, there seems to be a vitamin or supplement for anything and everything that ails you – whether you’re feeling stressed at work, aren’t getting enough sleep at night or long for healthier, shinier hair.

But how do you know when you actually need to take a supplement? How can you tell if they’re making a difference to your health and wellbeing? And which supplements are better left on the shelf?

New Zealand registered nutritionist Claire Turnbull told the Herald many people see vitamins and supplements as “a bit of an insurance policy”.

“The reality is, however, people massively overestimate their effectiveness – they don’t make up for a poor diet,” she explains.

“Supplements have a place, but they are useful for specific people in specific circumstances.”

Claire Turnbull is a registered nutritionist and the managing director of Mission Nutrition.

For pregnant women, vitamin D, folic acid and iodine are all essential to take throughout pregnancy and should be prescribed by your GP, Turnbull says.

You may also require supplementation if you’ve been diagnosed with a gut disorder or coeliac disease, but once again, these should be prescribed by your GP or a specialist.

“It’s not like, ‘I think I’ve got a bit of IBS [irritable bowel syndrome]. I think I just need to take a multi-vitamin’. Those two things don’t correlate,” she explains.

Other people who might need supplementation include the elderly, people who live alone or those who have issues with texture or chewing.

“Vegans or vegetarians who are likely to be short of zinc and iron may need supplementation, but that’s going to your GP, getting a blood test and seeing if you need it.”

Which supplements are worth taking?

However, there are some common vitamins and minerals in which you’re probably lacking.

“The average person in New Zealand is likely to be falling short [in] selenium, iodine – that is why people have an iodine supplement in pregnancy,” Turnbull says.

You can get the selenium you need from eating just two brazil nuts a day, while iodine can be found in fish, seafood and seaweed.

“Omega-3 is one where good-quality supplementation can be quite helpful for people, particularly if they don’t eat a lot of oily fish.”

Common deficiencies include Omega-3, vitamin D, B vitamins and iron, especially among older individuals. Photo / 123RF

A magnesium supplement can help with stress and sleep support. Iron deficiency is also common – but if you think you might be short on iron or zinc, it’s important to talk to your doctor and get a blood test before reaching for a supplement.

“You do not want to take those if you don’t need them,” Turnbull says.

“When you take too much zinc, it compromises the absorption of iron. When you take iron, it compromises the absorption of zinc.” Zinc can also inhibit your copper absorption.

What are the risks of taking too many supplements?

Turnbull says she sees many examples of “supplement stacking” – where people take too many different supplements without advice from their doctor.

“Having too much of some of these things in levels is toxic and can cause other kinds of challenges,” she says.

If you take too much of some supplements or vitamins, such as vitamin C, you’ll simply “pee it out”.

“But others do get stored in your body, and that’s where you’ve got to be aware that not all vitamins and minerals are the same in terms of their impacts on the body.”

Often, people reach for a supplement without realising that a deeper health issue could be causing their symptoms, Turnbull says. For example, tiredness could be a sign of diabetes or coeliac disease, while bloating or bowel issues could point to IBS or even bowel cancer.

Not all supplements are created equal. Photo / 123RF

“The concern that I have with supplementation [is] in the way that people access it today – just walking into a shop and being like, ‘Oh, this will make me feel better’.

“Supplements used to be iron, zinc, magnesium ... now they are named ‘Soothing Sleep’ and actually people don’t even know what they’re taking – they’re taking the name on the front of it, and have got really very little idea of the dose that they’re taking.”

For example, if you’re struggling to get enough shut-eye, Turnbull suggests looking at your sleep hygiene before forking out on a supplement.

“Look at the other things that affect sleep – daylight exposure; getting your room cold and dark; things that are cheap or free, like managing your caffeine intake.

“Supplements are like the sprinkles on top of the icing on top of the cake. And if you don’t have the foundations right, they’re not going to be the thing that changes everything unless you’re deficient.”

How can you tell if a supplement is working for you?

When it comes to supplements, the placebo effect is “very real”, Turnbull says.

“If it’s the only thing that you’ve changed in your life and after a couple of weeks, you feel genuinely better – well, who am I to say it’s not like that?

“If people take supplements safely and they follow the instructions on the packet and they’ve got the money to do it, that’s absolutely a personal choice. It becomes a concern when people start mixing them and not addressing the other things.”

Quality does vary when it comes to supplements. The price and the dosage is usually a telltale sign, so always check the ingredient list.

“If you buy something cheap, there’s a reason why it’s cheap.”

At the same time, beware of the often overpriced celebrity-endorsed supplements in aesthetically pleasing bottles.

While it’s not as glamorous, you’re probably better off spending your money on a review of what you’re eating from a registered dietitian or nutritionist.

It's important to look at your diet before starting a supplement. Photo / 123RF

“That’s only going to cost you the same amount as a couple of months’ worth of supplements,” Turnbull notes – and if you have health insurance, you can claim that cost back.

So before you part with your hard-earned cash for the latest herbal concoction on the pharmacy shelf, think about whether you should spend it in the fresh produce aisle instead.

“Fundamentally, a lot of people are absolutely better to spend that money on fruits and vegetables and eating whole food first,” Turnbull shares.

“A lot of the general supplements that people are taking are often not solving the problems that they think they are.”