The British Heart Foundation advises heart patients that mixing certain supplements with heart or blood pressure medications can make treatment less effective or increase side effects
10:22, 10 Nov 2026Updated 11:20, 10 Nov 2026
It is important to know what difference supplements might make to your medication(Image: Getty)
Millions of people take medication for cardiac conditions ranging from statins to combat high cholesterol to beta-blockers to reduce blood pressure. Yet, those managing health conditions will often explore whether incorporating additional vitamins or minerals into their diets could enhance their general wellbeing.
Data from Which? reveals that approximately three in four people consume some form of supplement, be it a vitamin, mineral or food supplement. Nevertheless, according to the NHS, the majority of people have no need for vitamin supplements and can obtain all essential nutrients from a healthy, balanced diet, with the exception of vitamin D during the autumn and winter months.
Despite this, many continue to spend their money on such products, with estimates suggesting around £4.1billion is spent on dietary supplements across the UK every year. However, according to the British Heart Foundation, certain supplements should never be combined with medication.
An estimated 16 million people in the UK suffer from high blood pressure(Image: Getty Images)
It says: “It’s easy to assume that nutritional supplements like vitamins, minerals, antioxidants, herbal products and other food‐based supplements are fine to take, especially when they’re marketed as a ‘natural’ way to support heart health. But natural does not always mean safe, and supplements like St Johns wort, garlic and CoQ10 plus a range of vitamins are not automatically risk free.”
It adds: “Supplements can also interact with prescribed heart medications. Some may make your treatment less effective, while others can increase side effects. This is important if you take medicines for high blood pressure or high cholesterol, or if you’re taking blood‐thinning medicines.
“UK Government guidance is clear: nutritional supplements are not recommended for preventing or managing cardiovascular disease (CVD). Research does not show any heart‐health benefits, and high doses can even be harmful. For most people, a healthy, balanced diet gives the heart everything it needs.”
The guidance also urges anyone considering taking a supplement, or those already using one, to inform their doctor or pharmacist so they can assess whether it is both necessary and safe. Three types of medication and the supplements that can affect them were highlighted, reports the Mirror.
Blood pressure medication
The BHF states that numerous common supplements can interfere with blood pressure medicines, including calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors and beta blockers.
It advises: “Sometimes supplements make these medicines less effective, which can cause your blood pressure to rise or fall unexpectedly.”
St John’s wort
It says: “St John’s wort is a herbal supplement marketed as a natural mood booster. It’s widely available, but also well‐known for causing drug interactions. This is because it speeds up liver enzymes (particularly CYP3A4) that break down many medicines.
“St John’s wort can make some blood pressure medicines, such as calcium channel blockers like amlodipine, less effective. This can make it harder to manage your blood pressure.”
Garlic
It explains that while some research suggests that garlic supplements, especially at high doses, may slightly reduce blood pressure, particularly in those who already suffer from high blood pressure, the evidence is not sufficiently compelling to support any guidelines recommending it.
It warns: “If you take prescribed blood pressure medicines, garlic supplements could lower your blood pressure more than intended.”
Liquorice root
Liquorice root can elevate blood pressure by disrupting the body’s salt balance, leading to fluid retention, advises the BHF. It says: ” This can work against blood pressure medicine, worsening high blood pressure.”
Blood-thinning medicines
According to the BHF, certain supplements can interfere with blood-thinners by either heightening the risk of bleeding or increasing the likelihood of clots. This includes medications such as anticoagulants, like warfarin, direct oral anticoagulants (DOACs), such as apixaban and antiplatelet medicines like aspirin or clopidogrel.
Vitamin K
The BHF states that Vitamin K is essential for bone health and also assists with blood clotting. However, it cautions that foods naturally rich in vitamin K, such as liver, Brussels sprouts, broccoli and other green vegetables, as well as vitamin K supplements, can affect how the anticoagulant warfarin works.
Brussels sprouts are rich in vitamin K
It adds: “Too much vitamin K can make warfarin less effective, so the blood clots more easily. Too little vitamin K can mean the blood does not clot enough. That’s why people taking warfarin are advised to keep their dietary vitamin K intake consistent and avoid vitamin K supplements.”
Vitamin E
The BHF states that while vitamin E is frequently promoted as an antioxidant that could protect the heart, clinical trials have not demonstrated any benefits to cardiac health. It adds: “Some evidence also suggests that long-term, high-dose vitamin E supplementation may increase the risk of bleeding, especially if you take blood‐thinning medicines such as anticoagulants, DOACs or antiplatelets. UK Government guidance does not recommend vitamin E to reduce the risk of CVD.”
St John’s wort
St John’s wort also interferes with blood-thinners by accelerating how the body metabolises them, according to the experts. This renders the medicines less effective and raises the risk of clotting.
The BHF adds: “UK advice is not to take St John’s wort if you’re also taking anticoagulants, DOACs or antiplatelets. This matches wider UK Government guidance that St John’s wort interacts with many heart medicines.”
Omega‐3 supplements
While fish oil capsules, omega-3 blends, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) products are frequently marketed for enhancing heart health, cholesterol and inflammation, the BHF states that large clinical trials have demonstrated no benefit from taking omega-3 supplements to prevent heart attack or stroke. It adds: “Because of this, UK Government guidance does not recommend omega‐3 supplements for preventing CVD or lowering cholesterol.”
It notes that prescription-strength EPA is only used in specific circumstances to reduce triglycerides and is not the same as over-the-counter fish oil capsules. The charity adds: “At high doses, omega‐3 supplements may also increase the risk of bleeding.
“If you take blood‐thinning medicines, using both together may raise your bleeding risk. These blood-thinners include anticoagulants, DOACs and antiplatelets.”
Statins
The BHF also has advice for people taking statins. It says: “Some common supplements can interfere with how common statins like atorvastatin, pravastatin and simvastatin work.”
Vitamin B3
The charity says: “Vitamin B3 is also called niacin or nicotinamide. Some people take high‐dose niacin supplements because they’ve heard it can help lower cholesterol.
“Early research suggested that niacin could reduce ‘bad’ LDL cholesterol, raise ‘good’ HDL cholesterol and lower triglycerides, leading to its use with statins. However, more recent large studies have shown that while niacin can lower LDL cholesterol, taking it with a statin does not reduce the risk of CVD or stroke.”
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It further notes that in certain trials, niacin supplements were “linked to more side effects, including a higher risk of cardiovascular events and death”. It cautions: “UK Government guidance is clear that vitamin B3 is not recommended for lowering cholesterol or reducing cardiovascular risk.”
St John’s wort
The BHF warns: “St John’s wort is not recommended if you take statins. This is because it can lower the amount of statin in your blood, making it less effective at lowering cholesterol.”
CoQ10 enzymes
CoQ10 (Co-enzyme Q10) is marketed for ‘energy production’ and for those who experience muscle aches while taking statins, the charity explains. It adds: “However, the evidence is mixed, and CoQ10 has not been shown to reliably help people continue with statin treatment or reduce muscle symptoms. UK Government guidance is clear that people should not take CoQ10 to help them continue taking statin treatment.”
Vitamin D
Vitamin D plays a crucial role in maintaining healthy bones and muscles. The BHF states: “Some people also take it in the hope that it will reduce statin‐related muscle aches.
“However, studies have not shown that taking vitamin D helps with statin‐related muscle aches, even in people who have low vitamin D levels. UK Government advice is not to take vitamin D for this reason.”