Do supplements really work?

Miracle pills or misleading marketing?

Supplements are a lucrative business. Surveys indicate that around half of adults in the UK regularly take some form of dietary supplement.(1) Meanwhile, the global market for such products was worth an estimated 151.9 billion US dollars in 2021.(2) Predictions suggest this figure is only going to grow.

But do supplements work? With so many people taking them and so much money being spent, it’s an important question to ask. Are they the miracle pills companies claim them to be, or are we being misled by clever marketing?

Perhaps unsurprisingly, there isn’t a simple answer. That’s partly because there are countless types of supplements on the market, each offering its own supposed benefits. The efficacy of one has no bearing on the efficacy of others. Likewise, we as individuals are all unique, with different health concerns and requirements. What’s right for one person might not be right for another. Plus, to determine whether a supplement is effective, you need to know what you’re hoping to gain by taking it.

However, there is one thing we’re able to say with confidence. Although some supplements may be helpful, you shouldn’t use them as a replacement for eating a healthy and balanced diet. The belief that we can get all the nutrients we need by popping a pill every day is simply untrue. A multivitamin will not compensate for a poor diet, nor can it boost longevity or prevent chronic diseases.

What about more modest claims, though? Do supplements work to address deficiencies, reduce the risk of certain medical conditions, improve cognitive functions, or boost overall health? Let’s take a closer look.

Making sense of multivitamins

Firstly, how do supplements work? The general idea is that they provide us with specific key nutrients that the body needs. This could be one single vitamin or mineral, such as vitamin C or iron, or a combination of several. The latter are called multivitamins and minerals, and they are among the most popular supplements. Many people take them for an overall health boost. But are they effective?

Unfortunately, the evidence is mixed. For example, some studies have found that multivitamins may correlate with a decreased risk of heart attacks.(3) However, others suggest they have no such effect.(4)

Likewise, the research on multivitamins and cancer risk is also conflicting. There are studies which link such supplements with a reduced risk of particular cancers, whereas others have found no effect.(5)(6) More worryingly, some evidence suggests that taking supplements could actually increase the risk of developing certain forms of cancer.(7)

Overall, there is little scientific evidence to support the claim that multivitamins can significantly improve your health. Many of the positive correlations found may actually be because people who take supplements tend to live healthier lifestyles generally.

Yet taking multivitamins isn’t the only approach. So, do supplements work when they’re targeted at specific deficiencies?

Do vitamin D supplements work?

One of the most common supplements we are recommended to take is vitamin D. Nicknamed ‘the sunshine vitamin’, our bodies produce vitamin D when we expose our skin to sunlight.

However, many of us spend much of our time inside, and/or live in areas that get limited sunshine in winter. This can lead to deficiencies, especially because we only naturally find vitamin D in a small range of foods. This makes it more difficult to obtain from diet alone. In fact, studies suggest that around 13% of Europeans are severely deficient in vitamin D.(8) So, do supplements work as a way to counter this? Once again, the science is split.

Evidence suggests that vitamin D supplementation can help to improve the bone health of people who are deficient in it.(9) Indeed, the advice from the UK government is that everyone should take vitamin D supplements during winter.(10) However, this may not be necessary for those who get enough vitamin D from sunshine and their diet.

It’s also important to note that taking too many vitamin D supplements could be toxic. This is because it results in a build-up of calcium, which can weaken your bones and damage your heart and kidneys.(11)

Consequently, it’s preferable to get your vitamin D from more natural sources. This means spending time out in the sun (wearing sun cream!) and obtaining it through your diet. When it comes to the latter, fatty fish, fortified plant milks and hemp seed oil are all fantastic choices.

Do vitamin B12 supplements work?

If you follow a plant-based diet, someone will almost certainly have warned you about getting enough vitamin B12. It’s naturally found in many animal products, but is more difficult to obtain if you’re vegetarian or vegan. However, it’s not impossible to do so, and there are several plant-based sources of B12 out there. But do supplements work as an alternative?

Research indicates that B12 supplementation can be helpful for vegetarians and vegans.(12) This is especially because levels of the vitamin in plant-based foods are not always consistent. However, it is also possible to get sufficient B12 as a vegan without turning to supplements. You can do this by ensuring you include fortified foods in your diet. For example, many plant milks have added B12. Other good sources are nori seaweed and chlorella.

Alternative ways to get the nutrients you need

Let’s return to our original enquiry: do supplements work? It seems the answer is both yes and no, depending on the supplement in question and reason for taking it. While they won’t provide you with a miracle cure, they can help to counter specific deficiencies in certain people.

This brings us to another issue – are supplements the most effective way to achieve this? In the majority of cases, they don’t appear to be.

For most of us, getting the nutrients we need from our diet rather than supplements is preferable. There are many reasons for this. Firstly, it’s not always clear exactly what’s in a supplement. This is partly due to insufficient regulation and the inclusion of extra ingredients like binding agents and fillers. In addition, it’s difficult to judge the quality of any individual supplement.

Moreover, supplements tend to isolate one specific vitamin or mineral (or a collection of them in a multivitamin). With whole foods, on the other hand, you consume a multitude of nutrients and other natural substances all together. This enables them to work synergistically, resulting in greater health benefits.(13)

There are also certain key differences between natural nutrients, like those in food, and the synthetic ones found in supplements. This can affect the ease with which your body absorbs them. For example, studies suggest that we can absorb natural vitamin E twice as easily as synthetic vitamin E.(14)

Finally, you may be at greater risk of overdosing on vitamins and minerals if you get them via supplements. This is particularly true for fat-soluble vitamins like A and K, which can accumulate in the body to high levels.