The dietary supplements to take (and avoid) in every decade of your life

To supplement or not to supplement – it's a surprisingly divisive question in the multi-million-pound wellness world. Last week, a large US study concluded that multivitamins may slow brain ageing and memory decline. Yet according to epidemiologist and author Professor Tim Spector, a long-time naysayer to pill-popping, supplements have no health benefits whatsoever, and make "total mugs" of those who buy them, he said at the Hay Festival, urging people to focus on "real food" instead. It isn't the first time supplements have been deemed a waste of time and money.

So, are they for mugs?

Taking a nutritional supplement is a daily habit for 38 per cent of people in the UK, with Vitamin D being the most popular. Any dietician worth their salt will tell you to focus on getting micronutrients from food first, as they are typically better absorbed by the body. "Supplements aren't going to fix a bad diet," says nutritionist Daniel O’Shaughnessy. "You need to take the meaning of the word literally [to supplement], so support a healthy diet."

Sometimes you can very easily get your required nutrients from eating food. For example, eating one Brazil nut a day will give you more than your recommended daily allowance (RDA) of selenium, while adequate amounts of vitamin C are easily obtained from fruit and veg, such as broccoli, bell peppers or citrus fruit as part of a balanced diet. But if you’re plant-based and therefore don't eat meat, fish or dairy, B12 is going to be harder to come by.

"Sometimes, eating food alone just isn't enough," O’Shaughnessy says. The most obvious example is vitamin D, a hormone which is crucial for bone health and immune function. One in six adults in the UK are thought to be vitamin D deficient. Our bodies produce it from sunlight on the skin via cholesterol and you can get small amounts from foods, "but it's often hard to obtain and absorb in adequate amounts", says O’Shaughnessy.

So those with a deficiency, or who are at risk of low vitamin D, are advised to supplement – and everyone else during the winter, according to the NHS. But even Vitamin D can be contentious; in November 2022 a 25,000-person study found that "supplemental vitamin D3, as compared with placebo, did not have a significant effect on total fractures".

There are, however, times in your life, when you might benefit from supplementing as you may be more prone to deficiency, argues nutritionist and women's health specialist Hannah Alderson. "Wherever there are hormonal shifts, women in particular, may need more micronutrients, essential fatty acids and some amino acids, to function optimally." Another thing to consider, she points out, is that the soil quality in which produce is grown "has changed dramatically over the years, so minerals are harder to find in the diet. I always recommend looking at food first, but mineral and vitamin deficiencies are common".

At the same time, ‘self-supplementation’ has its own risks. Certain supplements can interfere with medication for example, or " you may just end up having a very expensive pee if you don't have the right guidance", Alderson says. Plus, not all supplements are created equal. "They are a little like shoes – you often pay for quality. Cheaper options can contain poor dosages and lots of fillers, not hitting the sides." Read the packet and look for what other ingredients have been added to bulk out the capsule or preserve ingredients, such as sucrose (sugar), binders, fillers and preservatives, advises O’Shaughnessy. You want a supplement with as few additives as possible. "In an ideal world, you would test to understand what (if any) supplements you actually need rather than take them for the sake of it," says O’Shaughnessy. "But this can be expensive, so if this isn't feasible, then adopt a less is more approach."

While there isn't really a one-size-fits-all approach to taking supplements – ideally you would only take them when you’re actually deficient in something – here are some examples of when you might want to consider it, according to experts.

"Pre-teens and teenagers (especially girls and young women who experience heavy periods) are at higher risk of iron deficiency anaemia, so eating plenty of iron-rich foods, such as leafy greens, is important," says Priya Tew, a registered dietitian from Dietitian UK.

"A supplement may be needed for those who are anaemic, but you should always get this checked out with a blood test first as iron supplements can lead to constipation – liquid forms are kinder on the bowels."

If you begin following a plant-based diet at any age, it's wise to be wary of your intake of not just B12 and omega-3, but also iron, selenium, iodine, calcium and vitamin D. Meanwhile, Alderson points out that some studies have shown that the oral contraceptive pill may reduce your ability to absorb certain nutrients – namely folic acid, vitamins B2, B6, B12, C, E and minerals like magnesium, selenium and zinc – from the food that you eat, "which over time could lead to depletions". So this could be a good time to consider either a B complex or good multivitamin.

For women coming off the pill, Alderson usually prescribes a probiotic, as some research suggests that it may alter the gut microbiome. She also recommends probiotics to anyone following a dose of antibiotics. "I would always suggest repopulating the gut with a probiotic strain such as saccharomyces boulardii, alongside eating plenty of fermented and fibre-rich foods." There are so many different probiotic strains out there, that it can be hard to know which one will work for you (without an expensive trial and error process), so this is something you should really speak to an expert about.

Women trying for a baby at any age are recommended to take folic acid, and certainly during the first 12 weeks of pregnancy. "Folic acid helps prevent birth defects known as neural tube defects," explains O’Shaughnessy. Look for non-synthetic active forms of folate, such as L-methylfolate. During pregnancy and postpartum, "omega-3 is needed by the bucketload for both baby and mum, and low omega-3 status has been linked in studies to postnatal depression", says Alderson. "It can be hard to meet your requirements through diet alone, and if you’re relying on vegetarian sources you have to be able to convert omega-3 to the active form – not everyone is efficient at this conversion so supplementation can be useful."

As women approach perimenopause and menopause and the hormone fluctuations that come with it, this is another stage in life when you might benefit from supplementing. "I usually recommend omega-3, to support brain health, plus a great multi specific to this hormonal shift. Magnesium can also be very effective in times of high stress or anxiety," Alderson offers.

Magnesium is involved in more than 300 biochemical reactions in the body, "it comes in many forms and people use it for different things", says O’Shaughnessy, who advises avoiding magnesium oxide altogether, as it " isn't absorbed well". "Think about magnesium citrate or glycinate instead."

During menopause, "a woman may need support with bone health, by taking calcium and vitamin D, or perhaps digestion to absorb nutrients better," he continues. Declining oestrogen levels can slow digestion, which can lead to issues like constipation, bloating and gas, so you want to up your fibre intake and some women may also consider taking a probiotic.

As your body ages you may need extra protein to help maintain muscle mass and bone density, says Tew, either from food or powder supplements. "Maximising your nutrition is key here, again the focus should be on your diet, but some may feel a supplement helps provide that security.

"Just avoid taking megadoses of individual vitamins or minerals without knowing you need them – it can be detrimental as you can overdose on these with side effects or they can compete with each other in your system."

The recent US study, conducted by Columbia University and Harvard University, gave 3,500 adults over 60 a daily multivitamin, sold as Centrum Advance in the UK – and then tested their cognitive abilities every 12 months with an online test. By the end of the first year memory function had improved significantly in those taking the pills and this was sustained throughout the three-year study. Effects were more significant in those with underlying heart disease.