Nutrition Supplements — Do You Really Need Them?
Walk into any pharmacy or health store, and you’ll see shelves full of vitamins, minerals, and “wellness” products promising stronger immunity, better mood, and more energy. It’s no surprise that supplement use is common, and a BMJ report found that 36% of the UK population takes some form of supplement (Zhang FF et al., BMJ, 2020), and interestingly, many of these are taken by people without any signs of deficiency. While supplements contribute to nutrient intake, food fortification (like iodine in salt, vitamin D in milk, and B vitamins in flour) has already eliminated most major deficiency diseases such as goitre, rickets, beriberi, and pellagra in high-income countries, but remain more prevalent in low-income regions. So, do most of us actually need supplements? Let’s explore what the science and the NHS say.
What the Evidence Shows
Most randomised controlled trials (the strongest form of evidence) show no clear benefit from taking vitamin, mineral, or fish oil supplements for preventing chronic diseases, unless a deficiency exists. Observational studies sometimes suggest benefits, but people who take supplements often already have healthier lifestyles, which skews results. Examples from research include:
The BMJ review which found no consistent benefit of supplements in preventing major non-communicable (chronic or non-infectious) diseases like heart disease or diabetes.
JAMA publications reported mixed evidence for vitamin D and calcium where Vitamin D or calcium did not reduce fracture risk (Zhao J-G et al,. JAMA, 2017), but combined vitamin D plus calcium slightly lowered fracture risk in older adults (Yao P et al,. JAMA Network Open. 2019).
High-dose vitamin D (4,000–10,000 IU/day) reduced bone mineral density compared to lower doses (Burt L.A, et al,. JAMA 2019).
Men taking 1000 mg/day or more of calcium supplements had higher all-cause mortality(death), while calcium from food showed no harm (Yang B et al,. Am J Clin Nutr, 2016).
Randomised trials reduce bias, but often involve high-risk groups, so results may not always apply to healthy people.
Supplements and Immune Health
Many people turn to supplements to “boost” immunity. It’s true that vitamins A, C, D, E, and minerals like zinc and selenium are essential for immune function, and that deficiencies can increase infection risk. However, for well-nourished individuals, routine supplementation doesn’t prevent infections, and high doses can cause harm. Evidence highlights:
Vitamin D: Helps prevent respiratory infections mainly in people with low vitamin D (Martineau AR, et al,. BMJ, 2017).
Vitamin C: Doesn’t prevent colds but may shorten their duration, especially for those under physical stress (Hemelia H and Chalker E. Cochrane Database of Systematic Reviews, 2013).
Zinc: Lozenges may shorten cold duration if taken early, but prevention benefits are unproven Singh M and Das RR. Cochrane Database of Systematic reviews, 2013).
Selenium: Supports immune markers mainly in people with low levels (Filippini T et al,. Am J Clin Nutr, 2023).
Antioxidant megadoses (vitamin A, E, beta-carotene) have been linked to higher mortality (Bjelakovic G et al,. JAMA, 2007).
The bottom line is that supplements may help only if you’re deficient. Otherwise, a balanced diet is more effective and safer.
The Ideal Scenario: Getting Nutrients from Food
For most people, whole foods provide all the nutrients the body needs. Fruits, vegetables, wholegrains, lean proteins, nuts, and seeds don’t just give vitamins and minerals, they also provide fibre, antioxidants, and phytonutrients that work together in ways supplements can’t replicate. Nutrients in food exist within a complex matrix that enhances absorption and their effects (Townsend JE te al., Front Nutr, 2023). In contrast, nutrients from pills often act differently once isolated. For healthy individuals, supplements are usually unnecessary, and excessive intake can even be harmful.
When Supplements Are Recommended
There are two key supplements the NHS recommends for most people:
1. Vitamin D (the “Sunshine vitamin”), which supports bone health, muscle function, and immune regulation is produced naturally when skin is exposed to UVB sunlight. However, in the UK, sunlight isn’t strong enough from October to March and people may not produce enough vitamin D. People with darker skin, limited outdoor exposure, or who cover most of their skin are also at risk of low levels. Therefore, the NHS advice that everyone aged 4+ years should take 10 micrograms (400 IU) of vitamin D daily in autumn and winter.
2. Folic Acid (Vitamin B9) is essential for women trying to conceive or in early pregnancy. It helps prevent neural tube defects (like spina bifida). The NHS advice to take 400 micrograms daily before conception and during the first 12 weeks. Most adults can meet recommended intakes (200 micrograms/day) through leafy greens, lentils, chickpeas, and fortified cereals.
Visit the NHS website for an overview of all vitamins and minerals with sound advice: www.nhs.uk/conditions/vitamins-and-minerals/
The Risk of “Just in Case” Supplementing
Taking supplements “just in case” might seem harmless, but that’s not always true.Water-soluble vitamins (like B and C) are excreted easily, but fat-soluble vitamins (A, D, E, K) can build up and become toxic. Potential risks include:
Excessive pre-formed vitamin A (from supplements, not plant sourced) has been shown to cause liver steatosis, fibrosis and even cirrhosis in chronic use cases (Pestalardo ML et al,. World J Hepatol, 2025).
Excessive pre-formed vitamin A can effect bone resorption and increase risk of risk fracture and hypercalcemia (Munther S et al,. Cleve Clin J Med, 2022).
Iron overload may present with vomiting, diarrhea and liver damage upon excessive intake or absorption failure (Liu Y et al,. Biomed Pharmacolther, 2023).
Chronic zinc supplementation at doses exceeding ~60 mg/day can impair copper absorption, reduce immune function and cause gastrointestinal upset (Devarshi PP et al,. Nutrients, 2024).
So, if you are thinking of taking supplements without advice from a healthcare professional, it would be good to think twice. Remember, supplements can’t make up for an unhealthy diet or lifestyle. The best health outcomes come from whole foods, physical activity, quality sleep, and stress management, not pills.
When Supplements Can Help (With Professional Advice)
There are times supplements are beneficial under proper guidance. These include during pregnancy or preconception (folic acid, vitamin D, and sometimes iron); or for vegans or vegetarians who may not obtain enough vitamin B12, iodine, or omega-3s due to their scarcity of these nutrients in plant foods. People with medical conditions or restricted diets may also require supplements where nutrient absorption is reduced (for example, coeliac disease, inflammatory bowel disease), and older adults or those with limited sun exposure may require vitamin D and sometimes calcium for bone health.
If you suspect a deficiency, always speak with your GP, pharmacist, or registered dietitian before starting supplements.
The Final Takeaways
For most healthy people, supplements are not essential. A balanced, colourful, whole food diet provides nearly everything your body needs. Supplements have their place, but they’ll never replace real food as the foundation of sustainable health, and should only be taken under advisement from a healthcare professional or registered dietician.
