The vitamin myth: do we really need vitamin supplements?

Walk into any pharmacy or health store and you’ll see shelves packed with supplements like multivitamins, cod liver oil, herbal remedies, and more. They’re everywhere, promising everything from stronger immunity to glowing skin. It’s no surprise that nearly ninety percent of Europeans have taken a supplement at some point in their lives. Many of us take them hoping to feel healthier, more energetic, or just to give our immune system a boost. ¹

But do these pills, powders, and capsules actually work? With so many options on the shelves, it’s hard to tell what benefits our health and what’s just clever marketing. Are supplements really improving our well-being, or are we being sold a dream in a bottle? 

Let’s explore some of the most popular supplements on the market and see which supplements might benefit your health and who should be taking them. By the end, you’ll have a clearer idea of what’s worth taking and what might be better left on the shelf.

The rising market for supplements

Globally, the supplement industry is booming. According to a 2024 report, the global vitamin supplement market is expected to grow from 49 billion euros in 2024 to over 100 billion euros by the end of 2034.²

The growth is driven by a lot of factors, including:³

• An ageing population
• Increased health awareness
• A shift towards preventing illness before it begins

But it’s not just about health needs, it’s about lifestyle, too. From collagen powders stirred into morning smoothies to vitamin D drops promoted by wellness influencers, supplements are no longer something for middle-aged and older people.

While many people still buy supplements in pharmacies and supermarkets, online shopping has transformed the way we buy them. The rise in online supplement sales is closely tied to wellness trends and the persuasive power of influencers on social media.⁴ 

Today, many supplements have become popular, not because of science but because of social media. People are influenced by what they see online. Ashwagandha is a special plant that some people take to ease stress and help with sleep, but scientists are still figuring out exactly if and how much it helps.⁵ In 2024, ashwagandha was one of the most searched-for supplements in the UK, with over 2 million searches.⁶

This recent surge in popularity was mostly due to a TikTok trend.⁷ Before we look at some of the most popular vitamins people are buying, let’s first see how our bodies use them.

What are fat-soluble and water-soluble vitamins? 

Vitamins come in two main types: fat-soluble and water-soluble.⁸ The difference between them impacts how your body takes them in and what it does to them. 

Fat-soluble vitamins

These include vitamins A, D, E, and K. These vitamins need fat from food to be absorbed. Once your body takes them in, they are stored in your liver and body fat for when the body needs them.

You can get these vitamins from foods like: 

• Vegetable oils: Sunflower oil, olive oil, avocado oil
• Nuts and seeds: Almonds, hazelnuts, pine nuts 
• Egg yolks
• Fish oil: Salmon, sardines, mackerel
• Leafy greens: Broccoli, spinach, Brussels sprouts
• Pulses: Lentils, chickpeas

Because these vitamins stay in your body for a long time, taking too much of them in supplement form can be harmful. But if you eat a healthy, balanced diet, you’ll probably get enough of these vitamins naturally from your food. 

Water-soluble vitamins 

These include vitamins B and C. These vitamins do not stay in your body. Whatever your body doesn't need gets flushed out in your pee. That means you need to eat foods with these vitamins regularly to keep your levels up. 

Good sources are:

• Fruits 
• Vegetables 
• Whole grains 

Since your body can’t store them, it’s essential to eat a variety of healthy foods every day. 

Popular supplements

Vitamin D

In recent years, vitamin D has quietly become one of Europe's favourite supplements.⁹ 

Vitamin D is important for our health. It helps our bones stay strong and keeps our immune system working well. But how much do we need? And should we all be taking vitamin D supplements?

The answer isn’t simple. Vitamin D is naturally present in a few foods (egg yolks, oily fish, fortified cereal), and our bodies make vitamin D when our skin is exposed to sunlight.¹⁰ But during the cold, gloomy months, it can be harder for our bodies to make enough. People who spend most of their time indoors, those who cover up with clothing, or those with darker skin, may need a little extra vitamin D all year round. ¹¹

A 2022 report claimed that about 1 in 6 adults and about 20% of children in the UK have low levels of vitamin D. ^12 13 It recommends they take a daily supplement of 10 micrograms (μg) during the cold season.

But this only applies to about 20% of the population—what about everyone else? And what counts as “low” vitamin D? Different experts have different opinions on how low is too low.

According to national guidelines, vitamin D deficiency is defined differently across countries. 

• In Poland, vitamin D is considered too low if the level is 20 ng/mL or less¹⁴
• In the UK, vitamin D is considered too low if the level is 10 ng/mL or less¹⁵
• In Germany, vitamin D is considered too low if the level is 12 ng/mL or less¹⁶

Also, multiple factors can determine how much vitamin D we need, including

• Where we live
• Our current levels of vitamin D
• Certain health conditions
• Genetic makeup
• Our diet 
• Sunscreen use 

The amount of vitamin D a person needs can vary based on many things. It's a personal need, not a one-size-fits-all amount. The safest way to know how much vitamin D you need is to talk to your doctor or dietitian.

Fish oil

Omega-3 capsules or fish oil are another popular supplement in Europe. The omega-3 supplements market in Europe is expected to reach a projected revenue of almost 3 billion euros by 2030.¹⁷

These tablets are supposed to protect the heart, reduce inflammation, improve mental health, and even increase lifespan. But the science isn’t clear. 

• A study from 2018 in the New England Journal of Medicine found that omega-3 supplements didn’t lower the risk of heart attacks, strokes, or heart-related deaths in healthy people¹⁸ 
• Another study from 2013 in the same journal found that omega-3 supplements didn’t help people who were at risk for heart disease.¹⁸ 
• The same study found that omega-3 supplements might be helpful for people who don’t eat fish often.

Supplements may help only if you don’t eat any fish. But if you can eat foods with omega-3s—like oily fish—it’s the better option as real food has lots of other good nutrients that pills don’t.

Superfood powders

You might have seen those brightly coloured superfood powders all over social media. They're everywhere — blended into smoothies, poured into fancy glasses, and praised for their supposed health-boosting powers. They’re like a modern version of multivitamin pills and promise all sorts of health benefits. 

These drinks work like a regular multivitamin. They provide nutrients, but often much more than your body needs. Some have been known to have more than 500% of the daily value for vitamin C and B. These vitamins are water-soluble, so your body simply gets rid of the extra intake in your pee. 

Some superfood powders also contain excessive amounts of Vitamins A, D, E, and K. As these are fat-soluble vitamins, your body stores them rather than flushing excess out in your pee. Having too many fat-soluble vitamins in your system can be harmful. Taking too much vitamin E can cause blood thinning, interfere with blood clotting and even an increased risk of stroke.¹⁹ Superfood powders might seem healthy, but they often give you way more vitamins than your body needs which can be a waste of money or even harmful to your health. 

When supplements can help

Health experts say that for most people, spending money on supplements is not necessary.²⁰  A 2022 European study found that 97% of people take vitamins to improve their overall health and strengthen their immune system. ¹ But if you’re already eating a healthy diet, these supplements usually don’t make a difference. Studies also show that additional vitamins and minerals don’t help prevent cancer, heart disease or memory loss.²¹
In certain cases, supplements can support your health. Especially when used correctly and when supported by medical advice. Here are a few examples of people who may benefit from taking a supplement. ²²

• To treat or prevent a vitamin or mineral deficiency: Taking a blood test can help identify specific vitamin or mineral deficiencies, so you know what your body actually needs. People who follow a plant-based diet may not get enough vitamin B12.
• People with certain health conditions (e.g. Celiac disease or Crohn’s disease) may have trouble with nutrient absorption and may need supplements.
• If you are or may become pregnant. People who are pregnant or planning to become pregnant have certain vitamin requirements. A daily dosage of 400 to 800 micrograms of folic acid can help prevent birth defects. Most prenatal vitamins include folic acid, along with other important nutrients like calcium, iron and vitamin D.
• If you are middle-aged or older. As we get older, our bodies don’t absorb nutrients as well. Some older adults don’t get enough vitamin D, and others may need more calcium to keep their bones strong.

Talk to your doctor before starting supplements. They can help you decide what your body actually needs. ²²

How marketing hooks us on supplements 

The supplement market is thriving, with more people than ever taking vitamins and minerals, even though doctors and scientists say many of us don’t need them. 

Dr. Katie Suleta, a public health expert, believes the reason we continue to take supplements is clever marketing.²³ After years of studying how supplements are sold, she discovered some tricks that supplement companies use to make people believe they need them. 

“All natural”

The word natural on supplement packaging makes people believe they are better or safer.²³ But that’s not always true. Natural does not always mean better, and too much of a nutrient, like vitamin D, can be toxic. ²³ Also, while many believe vitamin C can stop the flu, science shows that the flu shot works better. ²⁴

“More is better”

Companies want us to believe that more nutrients are better, but that’s not how our bodies work. Adults only need about 75-120 mg of vitamin C daily, with those who are breastfeeding requiring the highest amount at 120 mg daily.²⁵ Many vitamin C supplements have 1,000 mg or more. So, that means you are peeing out most of your expensive supplement. For context, one regular orange or half a bell pepper provides enough vitamin C.

“Just in case”

Many people take supplements just in case, a habit called “action bias.” It feels easier than making a healthy meal, but pills can’t replace the benefits of real food. 

Curious how food can affect your mood? Find out more here.

But some supplements can even cause harm. Too much vitamin C can cause diarrhoea.²⁶ And some supplements, like St. John’s Wort, can interfere with other medicines. ²³ Always check the label for warnings about interactions, especially with medication.

Think before you buy

Overdoing certain supplements can be bad for your health. And while taking a few vitamins might seem like an easy health fix, most people don’t need extra supplements if they eat a balanced diet. 

Before buying a supplement, talk to your doctor to find out if you truly need it. This helps you avoid wasting money on unnecessary pills. Spending your money on a variety of fresh foods is often a better investment for your health than buying supplements recommended by an influencer.

Some people do need extra vitamins and minerals, such as older adults, pregnant people, or those with certain health conditions. But for most of us, the best way to stay healthy remains the same: eat a range of nourishing foods, get regular exercise, drink a lot of water and make sure to get plenty of rest.