A registered dietitian from the British Heart Foundation (BHF) has urged caution over garlic supplements, warning they may interact with certain medications.
Garlic supplements and medication interactions
Dell Stanford, a BHF dietitian with over 15 years' experience in NHS cardiac rehabilitation, said that while garlic is often taken for its health benefits, tablets and supplements may not suit everyone. She warned in March that "garlic supplements can interact with certain medicines such as blood thinners (anticoagulants) like warfarin." People on medication should always check with their GP before taking any nutritional supplements.
Harvard Health has also issued a warning: "Garlic supplements can increase the levels and effects of some medications for heart health, such as blood thinners (causing bleeding), cholesterol-lowering drugs (causing muscle damage), and blood pressure drugs (causing dangerous drops in blood pressure)."
What are anticoagulants?
According to the NHS, anticoagulants are medicines that help prevent blood clots. They are given to people at high risk of clots to reduce their chances of developing strokes and heart attacks. The NHS notes that a commonly prescribed anticoagulant is warfarin. Newer types, called direct oral anticoagulants (DOACs), are also commonly used, including rivaroxaban, dabigatran, apixaban, and edoxaban.
The NHS states that warfarin and the newer alternatives are taken as tablets or capsules, and there is also an anticoagulant called heparin that can be given by injection. The NHS also warns that those taking warfarin should avoid making significant changes to their normal diet, as this can affect the medicine. Most anticoagulant medicines are not suitable for pregnant women.
Do garlic supplements really work?
Some people take garlic supplements for their supposed health benefits, from supporting brain health to helping fend off the common cold, according to some studies. Harvard Health says garlic pills are often marketed as a way to lower cholesterol and blood pressure, but the evidence is mixed. Small studies suggest garlic supplements may slightly lower blood pressure.
Dietitian Dell Stanford cautioned: "At the moment, evidence for garlic supplements is too limited and inconsistent to recommend taking them for health benefits. It’s much better to include fresh garlic as part of a healthy diet, rather than relying on supplements."
