68 Harley Street London, W1G 7HE · Main Office
Also at Cromwell & Syon Bishops Wood · Multiple Locations
0203 9838 001 Call for Appointments
jessica@oneheartclinic.com Rapid Response to Enquiries
Expert London Cardiologist for your Heart Health
Millions of people take supplements hoping to protect their heart. Some may offer modest benefit — but many are unsupported by clinical evidence, and a number carry real risks, particularly when combined with heart medications. This guide gives you an honest, evidence-based assessment of the most widely used supplements.
The global supplement industry is worth over £150 billion and growing rapidly. Patients arrive in clinic taking five, ten, sometimes fifteen different supplements — often in addition to prescribed cardiac medications. Most are seeking the same thing: to do everything possible to protect their heart and their health.
That instinct is understandable and admirable. But the supplement industry operates in a largely unregulated space where marketing claims routinely outpace evidence, and where the line between "food supplement" and "medicine" is exploited commercially.
This guide does not take the position that supplements are always useless or harmful. Some have plausible mechanisms and modest evidence. A few have genuine clinical support. But the honest answer for most is that we do not have the evidence to recommend them, and some carry real risks that are poorly understood by those taking them.
My position in clinic: I ask every patient what supplements they take and review them without judgment. Some I am comfortable with. Some I ask patients to stop, usually because of drug interactions. What I always want is an open conversation — please bring your supplements to your appointment.
Each supplement is rated using the evidence available at the time of writing. Evidence ratings reflect the quality and size of cardiovascular-specific clinical trial data, not mechanistic studies or animal experiments.
The following interactions are not theoretical. They are documented in clinical case reports and pharmacological studies, and some have caused serious patient harm. If you take any of these cardiac medications, please review this table carefully and bring any questions to your next appointment.
The golden rule: Tell your cardiologist, GP, and pharmacist about every supplement you take — including herbal teas, protein powders, sports supplements, and anything bought from a health food shop or online. Many patients consider supplements categorically different from "medication," but from a pharmacological interaction standpoint, they are not. The interactions above are well-documented in clinical practice. Disclosure costs nothing; undisclosed interactions can cause serious harm.
Understanding how supplements are regulated — or rather, how minimally they are regulated — is essential context for evaluating any health claims made on packaging.
In the UK, food supplements are regulated by the Food Standards Agency (FSA) — not the Medicines and Healthcare products Regulatory Agency (MHRA). This means no clinical trial evidence is required before a supplement can be sold. A company does not have to prove a product works, or even that it is safe at the stated dose.
Ironically, UK and EU law prohibits supplement companies from making specific disease claims ("lowers blood pressure," "prevents heart attacks"). This is why packaging uses vague language like "supports cardiovascular health" or "contributes to normal heart function." These phrases are legally safe marketing language, not evidence-based claims.
Studies testing commercial supplements have found that label accuracy is frequently poor — products may contain far more or less active ingredient than stated, or be contaminated with other substances (including in some cases undisclosed pharmaceutical drugs). Third-party tested products (NSF, USP, Informed Sport certification) offer better quality assurance.
"Natural" is a marketing term, not a safety classification. Arsenic, botulinum toxin, and many highly toxic alkaloids are entirely natural. Conversely, all medicines are derived or synthesised from natural sources. The naturalness of a compound tells us nothing about its safety, efficacy, or interaction profile.
Despite the overall message of caution, there are specific situations where supplementation is appropriate, evidence-supported, or at least defensible. These are the circumstances where I might consider recommending a supplement in clinic.
Vitamin D deficiency is extremely common in the UK. Vitamin B12 deficiency occurs in vegans and with long-term metformin or PPI use. Iron deficiency anaemia requires supplementation. These are not discretionary — correcting genuine deficiency is evidence-based medicine. A blood test identifies these and guides appropriate supplementation.
If you cannot tolerate a statin or want additional LDL lowering alongside one, plant sterols (Benecol, Flora pro.activ — 2g/day) provide a proven 7–10% LDL reduction via a well-understood mechanism. This is one of the few non-prescription options with solid clinical evidence behind it.
High-risk patients (diabetes, established cardiovascular disease) already on maximally tolerated statin therapy may benefit from prescription-dose purified EPA (icosapentaenoic acid, 4g/day) — as studied in REDUCE-IT. This is a cardiologist-initiated prescription, not a health food shop supplement decision.
If you genuinely cannot or will not eat oily fish, a high-quality algae-derived omega-3 supplement (the original source of EPA and DHA) is a reasonable substitute. Algae-based versions are also suitable for vegetarians and vegans. Keep doses modest (1–2g) unless under medical supervision.
Psyllium husk (7–10g/day) has consistent evidence for 3–7% LDL reduction and is one of the closest things to a supplement that works via the same mechanism as food. If you cannot reliably eat legumes, oats, and vegetables in adequate amounts, psyllium is a safe and inexpensive option.
A blood test can estimate magnesium status. If low-normal or deficient — common with diuretic use, poor diet, or excessive alcohol — magnesium glycinate 200–400mg daily is safe and may provide modest blood pressure benefit. Inexpensive, generally well-tolerated, and physiologically rational.
If you decide to take a supplement, these principles will help you make a safer, better-informed decision.
Every single supplement, vitamin, herbal product, and sports nutrition product should be disclosed at every appointment. This is not about judgment — it is about safety. Bring the bottles if you are unsure of the names. Drug interactions are common, often silent, and occasionally dangerous.
The minimum bar for trusting a health claim is a randomised controlled trial in humans. Mechanistic studies (in vitro, animal), observational data, and testimonials are hypothesis-generating but not proof. Ask specifically: has this been tested in a double-blind RCT with cardiac outcomes? If not, treat the claim with appropriate scepticism.
Food contains thousands of bioactive compounds in physiological ratios — polyphenols, fibre, phytonutrients, antioxidants — that work synergistically in ways no capsule can replicate. A Mediterranean diet has more cardiovascular evidence than any supplement. Food is the original and most complex supplement.
Some patients reduce or stop their statin, blood pressure medication, or anticoagulant in order to "go natural" with supplements. This is dangerous. Cardiac medications have robust clinical trial evidence for reducing serious events and death. No supplement has equivalent evidence. Stopping prescribed medication should always be discussed with your cardiologist.
Patients on warfarin, apixaban, rivaroxaban, or dabigatran face the highest risk from supplement interactions. Anything with blood-thinning properties (nattokinase, high-dose fish oil, garlic extract, curcumin, vitamin E) can push anticoagulation to dangerous levels. If you are on an anticoagulant, discuss every supplement with your anticoagulation team or cardiologist before starting.
If you decide to take a supplement, select products certified by independent third-party testing bodies: NSF International, United States Pharmacopeia (USP), or Informed Sport. These certifications verify that the label accurately reflects the contents and that no undisclosed contaminants or pharmaceutical adulterants are present. This is especially important for supplements sourced online.
Several supplements that are safe at physiological doses become harmful at high doses: vitamin E increases mortality above 400 IU/day; vitamin A causes liver toxicity in excess; selenium causes toxicity at doses only modestly above the adequate intake. The dose makes the poison. Always stay within established upper tolerable intake levels.
The majority of supplement marketing now occurs on social media, where health claims that would be illegal on packaging are freely made. A confident Instagram doctor or wellness influencer presenting mechanistic or animal data as clinical proof is not equivalent to peer-reviewed evidence. Check whether a claim has been published in a reputable medical journal with independent peer review.
For vitamins and minerals, a blood test before starting supplementation tells you whether you actually need it. Supplementing without a baseline is pharmacologically unsound — you may be adding something you have in abundance or potentially pushing levels into excess. Your GP can arrange a full panel including vitamin D, B12, folate, iron studies, and magnesium.
Evidence on supplements changes. Something reasonable in 2022 may be contraindicated by 2025 data. Your medication list changes, meaning previous interactions may become relevant. Reviewing everything you take once a year — ideally with your cardiologist — ensures your supplement choices remain appropriate, safe, and aligned with your current health status.
For the lifestyle interventions with the strongest cardiovascular evidence, these guides cover diet, exercise, sleep, and the medications most commonly used alongside them.
A cardiology consultation with Dr Nijjer includes a full review of your medications and supplements — identifying any interactions and helping you make evidence-based choices for your individual situation.
Book a ConsultationMedical disclaimer. This page provides general educational information and does not constitute personal medical advice. Evidence ratings reflect published clinical trial data at the time of writing and may change as new research emerges. Drug interaction information represents currently documented interactions but is not exhaustive. Before starting, stopping, or changing any supplement — particularly if you take prescribed cardiac medications including anticoagulants, antiplatelets, antiarrhythmics, or statins — consult your cardiologist or GP. Do not stop prescribed medication without medical advice.