Do I need supplements?

As a nutritional therapist, the questions I’m most often asked are around supplements.  It’s not surprising.

Supplementation in the UK is a fast-growing, billion-pound industry.  Everyone has an opinion, and many people have something to sell you.  It's easy to end up with a drawerful of things you don't need, or miss the one or two things that could really help.

Nutritional therapists tend to use supplements in two ways.  We can optimise a diet: like filling a nutritional gap due to dietary principles, food preferences or medical conditions.  Or we can use them in controlled ways as a therapeutic tool: to address a specific gut bacterial overgrowth for example.  Targeted and used well they are one of our key tools.

But while I’m often asked should I be taking X?  Or what dose should I be taking of Y?  I’d love people to take a step back and ask are supplements even right for me: for my goals, symptoms and budget? 

So here are a few things to consider, starting with, how to keep yourself safe:

Can I take supplements alongside my medications? 

Sometimes the compounds in a supplement can interact with medication and affect its ‘mechanism of action’ (effectively, how well it works). That doesn't always mean you can't take a particular supplement; you can, with some, take them at different times of day from your meds. A nutritional therapist has access to clinical tools that flag these interactions and can suggest practical work-arounds. Never stop taking a medication without discussing it with your GP.

Can you take too many supplements? 

Yes. These are powerful compounds.  Iron, selenium, iodine and copper are just some that are essential for a healthy body but harmful in excess. Fat-soluble vitamins (D, A, K and E) dissolve in fat rather than water, so excessive levels can accumulate in body fat and the liver, and disrupt processes like calcium absorption, which we need for both bone and cardiovascular health. ‘More’ is not automatically better.  We are aiming, a bit like Goldilocks, for ‘just right’ levels of nutrients.

So how do I keep safe? 

Flag any supplements that you are taking at any medication reviews with your GP or health provider.  Stick to reputable supplement manufacturers and follow their guidance on dosage carefully.  Check you're not unintentionally duplicating a nutrient across two different supplements.  Testing, where possible, is the gold standard for establishing baseline levels and what your body needs.  Iron, Ferritin, Folate and B12 are often included in GP blood panels.  Other nutrients can easily be tested through a range of private functional nutrition tests.

Do I need supplements at all?

This depends on you, your lifestyle, your current health status, etc.  but here are some circumstances where you may wish to actively consider supplementation:

You exclude particular foods or food groups, and may be missing nutrients that diet would otherwise provide.  A vegan diet, for example, needs B12 supplementation.  Not all of us eat enough oily fish for our omega 3 requirements.  A very low-calorie diet or use of weight loss medication can leave nutrional gaps if not managed carefully.

You have digestive issues that impact on your ability to absorb nutrients.  Symptoms such as bloating, gas, cramping, diarrhoea or constipation can indicate issues with your gut.  If our gut barrier is compromised, we may not be able to absorb nutrients effectively.  Different forms of supplementation – ones absorbed via the cells in the mouth rather than the gut – can be useful here.

You need support for a particular life stage.  Unfortunately, we all have times of stress, lack of sleep, or life stages that require more nutrients like pregnancy or perimenopause.  A registered nutritional therapist can suggest supplements that may support you during these life stages.

Certain medications deplete nutrients as part of how they work.  A couple of common examples include statins: multiple clinical trials confirm they reduce Coenzyme Q10, a compound that supports healthy brain function – which can be a priority for many of us as we age. Long-term proton pump inhibitor (PPI) use reduces stomach acid, which can reduce the body’s ability to extract B12, calcium and magnesium from our food.  No medications should be stopped because of this – but we should be aware of these effects so that we can adapt our diets accordingly.

Where can I find out more?

In autumn 2026 a downloadable guide will be available on this website that gives more detail on which forms of supplements to choose, timing, and FAQs on the supplements people ask me about most.

Please sign up to Selina Fox Nutrition News to be the first to hear when this is available.

In the meantime, if you'd like answers tailored to you rather than general guidance, then the Supplement Sense Check was created for you. It starts with a detailed form covering your medical history, current medications, symptoms and goals, followed by 90 minutes together working through it properly.  You will leave with bespoke recommendations you can actually trust and leave the days of pulling random supplements off the shelf, or ordering something on a whim online, behind you.