Multivitamins or isolated vitamins?

Boost energy, improve sleep and strengthen immunity: are isolated vitamins more effective than multivitamins?

Posted by for Nutrition

Do you want to support your immune system, boost your energy and improve sleep quality? Then you’re probably thinking about taking a supplement or two – but should you go for a multi or isolated vitamin?

At the moment, it seems like nearly everyone is falling ill. If it’s not Covid, it’s some other bug that’s leaving people feeling shaky, sweaty and generally run down. And if you’ve caught neither yet, you might be thinking about boosting your vitamin intake to bolster your immunity.

And if that’s you, you might be wondering which supplements to take. Should you go for the simple, cheaper option and start taking a multivitamin? Or are individual vitamins and minerals a better option?

Multivitamins do what they say on the bottle: they’re tablets or formulas made up of umpteen vitamins and minerals. You might have taken one as a kid alongside your breakfast. They tend to include vitamins C, D and E, a B vitamin complex and minerals like iron, magnesium, zinc and copper. And if you’re feeling run down, they could well be the thing you start re-supplementing with – alongside your trusty Berocca.

For those of us arguably more into our nutrition, however, multivitamins may get sidelined for more specific nutrients. I take a vitamin D and B12 supplement every day (I’m a mixed-race vegan living in the UK, where sunshine isn’t always guaranteed). A daily zinc tablet is (hopefully) helping to maintain a good immune system, and my partner and I both swear by nightly drops of high-strength magnesium for sound sleep and reduced DOMS.

Multivitamins: cheap and convenient or a waste of money?

Registered nutritionist Marjolein Dutry van Haeften says that you’ve got to be careful with multivitamins because they won’t always give you what you need in the quantities that you need them, and some ingredients can end up competing against each other – like zinc, magnesium and iron. Does that mean that they’re not effective? “Potentially,” she says cautiously. “There’s such a huge difference between quality of supplements too.”

She warns you to make sure that everything included in a multivitamin is in an absorbable form. “Very often, for example, you’ll see that supplements contain magnesium oxide – but that’s not actually very well absorbed by the body. The only benefit that you might get could be more regular bowel movements, but that’s because (the mineral) is staying in the gut and not actually being absorbed.” You’re better off taking a multivitamin that contains magnesium glycinate instead, which is better absorbed.

But that’s not to say that multivitamins are to be avoided. Van Haeften says that, as a general rule, “if someone’s only taking a multi, it’s probably benefiting them”. Basically, a multivitamin is great if you’re going into it as a ‘I don’t know where to start, I just want to feel a bit better’. You just need to make sure that you go for a good brand. If you have specific concerns, however, then they may not be giving you what you need.

Lily Chapman, nutritionist at P3RFORM, is keen to stress that choosing to take a multi or isolated vitamin is totally down to the individual. “Multivitamin use may be beneficial if you want to gain short-term micronutrient support when you’re unable to eat a broad range of nutrient-rich foods (eg during illness or when travelling) and may also be more cost-effective.” Individual supplements, however, may be more useful if you’re after a higher dose of certain vitamins and minerals or want to treat or prevent certain deficiencies.  

Isolated vitamins: a more scientific approach to nutrition?

For those of us who have been diagnosed with anaemia, for example, a multivitamin that contains iron probably isn’t the best way forward, but neither, van Haeften explains, is taking an iron tablet: “I’d recommend getting a more comprehensive blood test first as there are different forms of anaemia. You need to know if you need iron or particular B vitamins that are going to help you use the stored iron you already have in your body.

Aside from your GP, another great place to go for advice on supplements, van Haeften suggests, is high-end health food stores like Planet Organic and Whole Foods, as often the people on the floor are trained to give advice.

It’s important to realise that no nutrients work in isolation in the body, so you’ve got to think about what you eat and drink, as well as the vitamins you consume. Vitamin D, for example, requires calcium to work in the body – it’s not going to do much good if your diet is nutritionally low.

While you're probably better getting checked by your GP, some high end health food stores may offer good quality advice on supplements.
While you're probably better getting checked by your GP, some high end health food stores may offer good quality advice on supplements.

“Taking nutrients in isolation can interfere with absorption of other nutrients,” says van Haeften. If you take high-dose B6, for example, it increases your need for zinc. And minerals can compete with absorption sites, so high concentrations of calcium and zinc can affect magnesium absorption.

“It’s a bit of a Goldilocks scenario where everything needs to be just right,” she says. “You don’t want to blindly supplement for long periods of time – it’s all about being mindful of what you’re putting in your body and asking for advice (from practitioners or trusted supplement companies) if you want more information.”

It’s worth flagging that any vitamin supplement from a reputable source is going to contain a ‘safe upper limit’ – which is defined as being a “dose that susceptible individuals could take daily, on a life-long basis, without medical supervision”. 

While that means it’s unlikely you’ll experience any toxic long-term effects, Chapman explains that those upper limits are based on chronic exposure, which could mean some people experiencing short-term, non-serious side effects. “It’s worth noting that the extensive number of supplements on the market means many have low quality control standards – meaning that contamination may be present”. 

How to choose the best vitamins for you

Before taking anything, van Haeften recommends getting your levels checked. While the NHS recommends we all take vitamin D, particularly during the winter months, she says that blindly taking vitamin D every day for a year could lead to our levels building up too high. “If you’ve been taking something for three or six months, it’s time to check what effect it’s having,” she says.

Both she and Chapman believe the absolute best way to get vitamins and minerals is through food. Unfortunately, however, dodgy digestive systems can stop us from absorbing all the nutrients from our food and it’s then that supplements can be really helpful. We also know that plant-based diets tend to be low in vitamin B12 and iron, so it’s worth thinking about supplementing those – and getting your levels tested by your GP. 

Chapman says that you want to undergo a cost-benefit analysis for any supplements that you’re thinking of taking, “incorporating the need, risk, effectiveness, safety and reliability of those under consideration”. She recommends asking the following questions before buying any kind of multivitamin or standalone nutrient:

  1. Is it safe to use?
  2. Is there evidence for its use?
  3. Does this supplement come from a reliable source?

Answering those can help to move towards a “food-first approach”, she says, “whereby intake only occurs when daily recommendations cannot be met through the diet alone, or if a diet cannot be altered to consume enough of the certain vitamin/mineral in hand”.

For more nutritional tips, visit the Strong Women Training Club.

Images: Getty

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Miranda Larbi

Miranda Larbi is the editor of Strong Women and Strong Women Training Club. A qualified personal trainer and vegan runner, she can usually be found training for the next marathon, seeking out vegan treats or cycling across London on a pond-green Tokyo bike.