Supplements: Helpful or Harmful? A Closer Look at Safety, Regulation, and the Evidence
Walk into any pharmacy or health food shop and you'll find shelves lined with supplements claiming to boost immunity, enhance energy, support sleep, reduce stress, and more. While some supplements can be useful in specific situations, they are often misunderstood and, in many cases, perceived as more beneficial or safer than they actually are.
High Consumer Confidence, Low Regulatory Oversight
Many people assume supplements are safe because they’re “natural” or widely available without a prescription. However, in most countries, including the UK and across the EU, supplements fall under the same regulation as foods not medicines. In the UK, responsibility lies with the Food Standards Agency (FSA) and Trading Standards, while the Medicines and Healthcare products Regulatory Agency (MHRA) may become involved when a product crosses into the realm of medical claims. In the EU, the European Commission oversees regulation, supported by scientific advice from the European Food Safety Authority (EFSA).
While supplement manufacturers must ensure their products are safe, properly labelled, and contain only permitted ingredients, there is no mandatory clinical testing for food supplements in the UK or EU and products can be sold without being reviewed for efficacy or long-term safety. However, any health claims made must be based on pre-approved, evidence-based statements from regulatory bodies such as the EFSA. For example, a supplement containing magnesium cannot claim to “relieve anxiety” as this would be considered a medicinal claim but it is allowed to state that magnesium “contributes to normal psychological function”, which is a general health claim approved by EFSA.
What does the Research Tells Us About Supplement Safety?
Although data in Europe is limited, findings from a large U.S. surveillance study estimated that around 23,000 emergency department visits per year were attributed to dietary supplements. Most cases were linked to a single supplement, not interactions with prescribed medications.
The most frequently implicated products were:
Weight loss supplements
Energy boosters
Sexual enhancement products
Micronutrients, particularly iron, calcium, and potassium
Children and older adults are especially vulnerable. Accidental ingestion by children accounted for one-fifth of emergency visits. Meanwhile, adults over the age of 65 were likely to experience hospitalisation due to excessive intake of high-dose nutrient supplements.
Natural Doesn’t Always Mean Safe
The term “natural” is commonly used in supplement marketing, but it can give a misleading sense of safety. For example, St. John’s Wort, a popular herbal remedy for mild depression, has been shown to interfere with over 200 medications in a major way, including oral contraceptives, anticoagulants, and chemotherapy drugs.
Even multivitamins, which many consider harmless, can contribute to excessive nutrient intakes especially when taken alongside fortified foods. Over time, this can lead to unwanted effects, such as vitamin A toxicity, iron overload, or imbalances in nutrient absorption.
What is Actually in the Bottle?
Another key issue is the accuracy of supplement labelling. Studies have uncovered discrepancies between label claims and actual content, as well as contamination with undeclared substances. In Europe, the Rapid Alert System for Food and Feed (RASFF) helps track such safety issues, but enforcement is often reactive rather than preventative.
To minimise risk, consumers are encouraged to look for third-party certifications. When choosing a supplement, check for independent testing or adherence to recognised quality standards. These marks indicate that the product has been tested for content accuracy and contaminants (though not necessarily for effectiveness).
Micronutrients: Not Just a Numbers Game
Our understanding of nutrients has evolved over time. In the past, much of the research focused on studying individual vitamins and minerals in isolation, which helped identify essential nutrients and prevent deficiencies. However, this reductionist approach doesn’t capture how nutrients actually behave in the body, where they interact with other compounds and have different effects depending on the individual.
Another important factor to consider is how nutrients from supplements are absorbed differently than those from food. Randomised controlled trials (RCTs) show that the absorption of nutrients from supplements can vary significantly compared to food sources. This difference is influenced by several factors, including the chemical form of the nutrient, the delivery system of the supplement, and the presence of other dietary components that can enhance or hinder absorption. Furthermore, individual factors like genetics, health status, age, and gut microbiota can affect how nutrients are absorbed and used by the body.
Given these variations in nutrient absorption and biological response, it’s clear that obtaining nutrients from whole foods is often the most reliable and beneficial approach. While supplements can be helpful in certain situations, they should not replace a varied, nutrient-dense diet. Understanding these differences is key to making informed choices about supplementation and improving overall health.
Practical Advice for Supplement Use
If you're considering taking a supplement, here are some evidence-informed tips:
Seek professional guidance. Speak with a GP, pharmacist, or registered dietitian, especially if you are on medication or have a medical condition.
Prioritise diet first. Supplements should fill specific gaps, not replace a healthy and varied eating pattern.
Regularly review your supplementation needs, as normal changes, such as, ageing, stress, pregnancy, or illness, may alter your supplement requirements.
Always disclose supplement use during health assessments even if your healthcare provider does not specifically ask.
Choose brands that undergo third-party testing for purity and potency. You can often find the testing certificate on a brand’s website or email them to ask for it.
Check the label, it should tell you the exact amount of a product in each dose as well as the expiry date. Avoid proprietary blends and supplements that do not list the exact amount of each ingredient as it is impossible to know the dosage of each individual item, potentially leading to under/overconsumption of specific nutrients.
Prioritise single ingredient formulations that target specific health needs, as doses can be adjusted to meet your requirements without also lowering/raising the dose of other nutrients.
Select supplements backed by robust scientific research regarding their efficacy and safety. Examine.com is a great independent, unbiased resource to consult for comprehensive information about various supplements.
Avoid high doses unless advised. More is not always better and can sometimes be harmful.
Be cautious of supplements that make bold claims, it is unlikely that they are true.
Final Thoughts
Supplements can have a role in supporting health, particularly for those with specific needs, dietary restrictions, or medically diagnosed deficiencies. However, they are not automatically safe and the science of how nutrients interact within the body is far more complex than taking one pill a day to “cover all bases”.
Given the current lack of rigorous pre-market testing requirements, it is up to consumers to make informed choices. Supplements should be approached with the same level of care and scrutiny as medicines. Use them intentionally, when needed, and ideally under the supervision of a qualified healthcare professional.
References
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https://www.food.gov.uk/business-guidance/food-supplements
https://www.legislation.gov.uk/uksi/2019/651/contents/made
https://food.ec.europa.eu/safety/labelling-and-nutrition/food-information-consumers/food-supplements_en
https://www.efsa.europa.eu/en/topics/topic/food-supplements
https://www.gov.uk/guidance/decide-if-your-product-is-a-medicine
