The vitamin con: Do supplements do anything or are we all being scammed?

For many of us, Christmas Day involved gathering together with extended family to eat, drink, be merry – and endure well-intentioned criticism so cutting it will haunt us all year. “You’re looking a bit peaky – have you been burning the candle at both ends?” a great-aunt might have enquired, after looking you up and down and observing the dark circles gouged under your eyes, and the pallid, puffy skin that hasn’t had a sniff of sunlight in months. “Are you getting enough vitamins?”

For the vast majority of people, the inevitable answer to this second question is “hell no” – particularly after a period spent largely consuming festive foods in 50 shades of beige. Regardless of the time of year, data from the National Diet and Nutrition Survey (NDNS) shows that fewer than 1 per cent of the UK population achieve all nine of the Eatwell Guide recommendations – a set of guidelines detailing how much of each food group we should be eating to achieve a healthy and balanced diet.

Analysis of the NDNS results by the Health and Food Supplements Information Service (HSIS) suggested that one in five UK adults are deficient in vitamin D, one in seven are deficient in calcium and one in 10 are deficient in vitamin A; 24 per cent of 11-18 year olds have low iodine levels; a quarter of women aged 19 to 64 have below-recommended intakes for iron; and 47 per cent of 11-18 year old females have below-recommended intakes for magnesium. More than a third of working-age adults have below recommended intakes for selenium, which plays a critical role in metabolism and thyroid function, and no population group is eating enough oily fish each week.

There have also been significant falls in nutrient intakes in the decade between 2009 and 2019, according to HSIS. Doesn’t it make sense, then, to simply take a shortcut to good health by swallowing a multivitamin every day? Alas! If only the solution was so simple.

Evidence that a standard A-Z multivitamin supplement will have much impact is scant, to say the least. A 2020 study of more than 20,000 adults published in the medical journal BMJ Open found no difference in disease or health conditions between those who took multivitamins and those who didn’t. A recent review of more than 80 separate studies on the effects of vitamin and mineral supplements in healthy adults, meanwhile, concluded that they were associated with little or no benefit when it came to preventing cancer, cardiovascular disease or death. “The quick answer is that there is no evidence of benefits for most people,” Professor Susan Fairweather-Tait, an expert in micronutrients at Norwich Medical School, tells me.

The reason standard multivitamins, including the world-leading brands, have such a minimal impact in terms of observable benefits is down to quantity and quality of ingredients, says Sarah Carolides, a nutritionist at The Lanserhof Clinic and head of nutrition at supplement startup Zooki.com.

“When you look at some of the pile-them-high, sell-them-cheap supplements, like the most popular brands in the world, they’ve got synthetic ingredients in there,” she says. These include DL-alpha tocopheryl acetate, a synthetic form of vitamin E derived as a waste product from the petrochemical industry; a synthetic form of vitamin B1 called thiamine mononitrate, which is a byproduct from the coal industry; and Chromium (III), a “completely inorganic, mass-produced chemical”. “A lot of the very cheap ones are full of absolute rubbish,” adds Carolides. Research found that 10 per cent of fish oil supplements bought from major retailers were “completely rancid”.

Then there are the actual quantities of the vitamins and minerals involved in supplements, which much of the time may be too low to have any effect on the body. One piece of research in the US revealed that out of 57 dietary supplements purchased online, 40 per cent of them contained none of the nutrients advertised on the label and a further 50 per cent contained some but not the full amount.

“Broadly, I would say cheap multivitamins and minerals are not going to have a tangible effect on most people’s health,” Carolides says. It’s why experts like genetic epidemiologist Tim Spector can take aim at the industry and loudly proclaim that most vitamins and mineral supplements simply don’t work.

The official party line from the NHS is that “most people should get all the nutrients they need by having a varied and balanced diet”. But this is harder to achieve than people might imagine for a number of reasons. One is psychological – most of us, amid busy, hectic lifestyles, don’t divert too much attention or brain space to what we’re putting into our bodies.

“In theory, vitamins and minerals can be obtained from a healthy, balanced diet but so many factors conspire to ensure that this doesn’t happen: reliance on high fat, high sugar, micronutrient-poor meals and takeaways, lack of time to plan and prepare healthy meals, fad diets and cutting out of nutrient-rich food groups such as meat and dairy,” says HSIS nutritionist Dr Pamela Mason. As Carolides points out, many of us will have the same diet year-round, eating a pretty much identical breakfast and lunch every day, with a bit of rotation when it comes to dinners (though even this can be minimal from week to week).

Dr Pamela Mason, HSIS

“The body is designed to take in vitamins and minerals from food; we didn’t evolutionarily develop to need supplements,” she explains. “But there are several big issues here, including the quality of our soils.” This quality has been hugely degraded over the past century, thanks to over-farming, a lack of crop rotation, and the use of chemical fertilisers and pesticides. “That has severely depleted our soils of minerals, and plants don’t make minerals – they just absorb them from the soil.” It stands to reason that, if the soil they’re grown in doesn’t have much in the way of vitamins and minerals, there’s no way the fruit and veg itself can have much either.

Worse still, some people might think that taking a multivitamin means they don’t have to worry too much about nutrition, believing they can just “take a pill” to make up the shortfall. “It seems like an easy win, doesn’t it?” says Carolides. “I can keep eating the pizza and drinking the Chardonnay, but I’ll just take my multivitamin every morning.” She says it ties in to a greater movement towards health hacking and biohacking – communities who look to technology such as wearable devices and $5,000 smart ice baths to increase their life expectancy, instead of going back to basics. “It all feeds into that tech ‘quick win’ mentality – a pill for an ill – when actually you’ve got to put in the work to get people eating well, moving well, sleeping well. That is at least 80 per cent of keeping your body healthy.”

Where does that leave us, then – if multivitamins don’t provably work but we’re unlikely to be getting enough micronutrients from our food? First off, focusing on the bits we’re at risk of being low on and prioritising those specific supplements rather than a “catch-all” multivitamin has more chance of making a legitimate difference to our health and wellbeing.

The experts all highlight vitamin D – in reality a hormone, not a vitamin – which is needed for the absorption of calcium. Vitamin D deficiency adversely affects bone health and results in rickets in children and osteomalacia in adults. It’s the one we get from sunshine, which is why the UK government advises taking a supplement during the winter months – because we simply cannot make enough vitamin D from skin exposure to sunlight between the months of October and March, and there are a very limited number of foods containing vitamin D.

“Taking vitamin D is an absolute no-brainer in this country,” agrees Carolides. “Vitamin D affects the mood. It can decrease anxiety, increase feelings of wellbeing, and really affect your sleep.” The darker your skin is, the less vitamin D your skin makes – so it becomes even more of a priority.

Professor Fairweather-Tait also recommends an iron supplement for women of childbearing age and pregnant women; evidence has shown that daily iron supplementation is associated with reduced risk of anaemia and iron deficiency in menstruating women and adolescent girls, according to the World Health Organisation.

She gives a nod to vitamin B12 for vegans and vegetarians – one study found that 92 per cent of vegans were deficient compared to 11 per cent of omnivores, and evidence links deficiency with increased risk of a range of neuro, vascular, immune and inflammatory disorders – and folate supplements (eg folic acid) for pregnant women. The reason for this last recommendation is that nine in 10 women have such a low blood level of folic acid that they risk having a baby with a neural tube defect (NTD) – a serious birth defect in the narrow channel that forms the brain, spinal cord and backbone.

Essential fatty acids like Omega-3 are also high on Carolides’ list: “Unless you’re eating a load of oily fish, nuts and seeds, they’re just crucial. You need these essential fats for the brain; they actually make the myelin sheaths that go around the neurons. You need them for metabolism. You need them for protection of the cardiovascular system. They bring down cholesterol. They’re really, really important.”

Then there’s collagen – somewhat hijacked by the beauty industry these days, but still essential as the “glue of the body – ligaments, tendons, bones, teeth: absolutely everything is held up by collagen”. Our natural production of it starts to decrease from the age of 30, and then rapidly declines during the menopause. And at this time of year, Carolides also highlights vitamin C for an improved immune system and energy levels. “You’d need to eat a field of oranges or berries to get a really good amount of vitamin C, and it’s one of those ones that just peps you up straight away.”

Sarah Carolides, nutritionist

With all of these, the quality of the supplement is vital – something that can be hard for a layperson to determine just by looking at the indecipherable ingredients label. Carolides advises heading to an independent health food shop to ask for advice, or consulting a nutritionist.

Can you have too much of a good thing? That depends on whether the vitamin in question is water-soluble or fat-soluble. With the former, go for your life – the body is only designed to absorb a certain amount, and the rest will be excreted from the body. For example, the body can absorb around 200mg of vitamin C; a supplement could contain 1,000mg, so 800mg of that is most likely going straight out again. With the latter, it is possible to build up toxic levels as they can remain stored in the body’s fat tissue and liver for a while; in 2023, for example, an 89-year-old man from Surrey who had been taking supplements for months died from a vitamin D overdose.

“All the fat-soluble vitamins can be stored in the body so could accumulate in tissues and the consequent body burden could have adverse effects on health,” says Professor Fairweather-Tait. “The vitamin that is most problematic is vitamin A. Pregnant women are advised to eat a limited quantity of foods high in vitamin A because of its potential toxicity.” Lung cancer risk has been associated with an excess of Beta carotene (found in many yellow, orange and green vegetables) and smokers are advised to avoid supplements that include it.

The major fat-soluble vitamins are A, D, E, and K; important water-soluble vitamins include C, B1, B2, B3, B4, B6, B7, B9 and B12. The metals can also cancel each other out if taken in too high a dose – if you overdo your iron, for instance, it can knock out your zinc or copper.

All that aside, taking the right supplements – good-quality ones that your demographic is known to benefit from – can make a genuine difference. “With some of the water-soluble vitamins, you’ll feel it straight away,” says Carolides. “Get a good hit of vitamin C, and it’s like having a cup of coffee but without the jitters. With vitamin D, you’ll feel it in your sleep. Get an influx of iron and you immediately feel it in your energy. Your eyes might be a bit brighter, your skin might be a bit better.”

Whether you take supplements or not, let’s be real: it’s going to end up being “New Year, Same You” like always. Then again, with deeper sleep and more get-up-and-go, who needs to unlock a whole new version of themselves?