Millions of people take medication for cardiac conditions, from statins to combat high cholesterol to beta-blockers to reduce blood pressure. Many also consider adding vitamins or minerals to their diets to support general wellbeing. However, the British Heart Foundation (BHF) advises that certain supplements should never be combined with heart or blood pressure medication, as they can make treatment less effective or increase side effects.
Supplement use and official guidance
Data from Which? indicates that approximately three in four people consume some form of supplement, whether a vitamin, mineral or food supplement. Nevertheless, according to the NHS, most 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 autumn and winter.
Despite this, around £4.1 billion is spent on dietary supplements across the UK every year. UK Government guidance is clear that nutritional supplements are not recommended for preventing or managing cardiovascular disease (CVD), noting that research does not show any heart-health benefits and that high doses can even be harmful.
Blood pressure medication interactions
The BHF states that numerous common supplements can interfere with blood pressure medicines, including calcium channel blockers, ACE inhibitors and beta blockers. It advises that supplements can make these medicines less effective, causing blood pressure to rise or fall unexpectedly.
St John's wort, a herbal supplement marketed as a natural mood booster, can make some blood pressure medicines such as calcium channel blockers like amlodipine less effective. Garlic supplements, especially at high doses, could lower blood pressure more than intended when taken with prescribed medicines. Liquorice root can elevate blood pressure by disrupting the body's salt balance, leading to fluid retention, which can work against blood pressure medicine.
Blood-thinning medicines and supplements
Certain supplements can interfere with blood-thinners by heightening the risk of bleeding or increasing the likelihood of clots. This includes anticoagulants like warfarin, direct oral anticoagulants (DOACs) such as apixaban, and antiplatelet medicines like aspirin or clopidogrel.
Vitamin K, found in foods like liver, Brussels sprouts and broccoli, as well as in supplements, can affect how warfarin works. Too much vitamin K can make warfarin less effective, while too little can mean the blood does not clot enough. People taking warfarin are advised to keep their dietary vitamin K intake consistent and avoid vitamin K supplements.
Vitamin E, often promoted as an antioxidant, has not been shown in clinical trials to benefit cardiac health, and long-term, high-dose supplementation may increase bleeding risk, especially with blood-thinning medicines. St John's wort also interferes with blood-thinners by accelerating how the body metabolises them, making the medicines less effective. UK advice is not to take St John's wort with anticoagulants, DOACs or antiplatelets.
Omega-3 supplements, including fish oil capsules and EPA/DHA products, have not been shown in large clinical trials to prevent heart attack or stroke. At high doses, they may increase bleeding risk, and taking them with blood-thinning medicines may raise that risk. Prescription-strength EPA is only used in specific circumstances to reduce triglycerides and is not the same as over-the-counter fish oil capsules.
Statins and interacting supplements
Some common supplements can interfere with how statins like atorvastatin, pravastatin and simvastatin work. Vitamin B3, also called niacin, has been linked in recent large studies to more side effects, including a higher risk of cardiovascular events and death, when taken with a statin. UK Government guidance does not recommend vitamin B3 for lowering cholesterol or reducing cardiovascular risk.
St John's wort is not recommended with statins because it can lower the amount of statin in the blood, making it less effective. CoQ10, marketed for energy production and statin-related muscle aches, has not been shown to reliably help people continue with statin treatment or reduce muscle symptoms. Vitamin D, while important for bones and muscles, has not been shown in studies to help with statin-related muscle aches, even in people with low vitamin D levels.
