Why some spices could be doing more harm than good to your health

All of us love a little spice in our life, but could how you season your food actually be harming your health?

Welcome to Ask Doctor Zac, a weekly column from news.com.au. This week, Dr Zac Turner explores the truth about some common ingredients.

QUESTION: Dear Dr Zac, I’ve been taking blood pressure medication for years without any issues – but I recently read that common spices I love and frequently use like ginger and black pepper can interfere with all types of medications. Now I’m starting to wonder: have my daily meals been affecting my meds this whole time? Or am I now just being paranoid to think my spice rack is doing more harm than good? – Warwick, 48, Canberra

ANSWER: Dear Warwick, I’ve got some spicy news for you – you’re not being paranoid. You may have been cooking up a storm, but some of your pantry favourites might have been quietly stirring up trouble in your bloodstream.

This is one of those alarming but fascinating medical blind spots that very few people talk about. While your spice rack might look innocent, the truth is that many everyday spices pack serious pharmacological punch. That’s right – your humble curry powder could be moonlighting as a biochemist, tweaking your enzyme levels while you’re just trying to enjoy dinner.

Let’s break this down.

Black pepper: The enzyme hijacker

You know that satisfying little crack of the pepper mill? Behind that spicy pop is piperine, a compound that slows down enzymes responsible for breaking down medications. If you’re on medications like propranolol or phenytoin, this could result in dangerously high drug levels in your system. While small amounts are usually safe, regularly consuming 2–4 tablespoons (yes, tablespoons!) of black pepper or popping high-dose pepper supplements can mess with your meds in a big way.

Garlic: Blood pressure’s double agent

Garlic is known for helping lower blood pressure – but for people already on blood pressure meds, this can become a double whammy. Too much garlic can cause your BP to drop too low, leaving you dizzy, faint, or worse. It also acts as a blood thinner, making it a risky companion to Warfarin or Aspirin.

Could how we season our food be harming our health/. Picture: iStock

Ginger, turmeric and friends: The bleeders

Ginger and turmeric are the golden children of wellness influencers, but they too carry hidden dangers. Turmeric’s curcumin and ginger’s gingerols can thin your blood, interfere with how drugs are absorbed, and even raise levels of immune suppressants like tacrolimus. If you’re on blood thinners, these spices could unintentionally supercharge your medication’s effects – and not in a good way.

Cinnamon, cloves and licorice: The silent saboteurs

Cassia cinnamon, the kind most commonly found in your local supermarket, contains coumarin, which can damage the liver in large amounts. Cloves contain eugenol, which can also affect the liver and interfere with blood clotting. Licorice? That sweet little herbal tea ingredient can raise your blood pressure and cause fluid retention – definitely not ideal when you’re on antihypertensives.

Could your spice rack be affecting your medications? Picture: iStock

So, should we all be terrified of tacos now?

Absolutely not. Culinary doses – what you’d normally sprinkle into a stir-fry or curry – are almost always safe. It’s when people start adding supplements, drinking litres of turmeric lattes, or chewing raw garlic like it’s gum, that we start to see real medical consequences.

Your best defence? Have a chat with your GP or pharmacist if you’re on long-term medication. Ask whether any of your go-to herbs and spices might be interfering. And please, don’t panic and toss your spice rack into the bin – just use your herbs with knowledge and care.

Aussies love spicy food. Picture: iStock

Because while spices can heal, boost, and flavour our lives, taken the wrong way they can also sabotage our health quietly, slowly … and without us realising.

So Warwick, your instincts were bang on. Your spice rack could be messing with your med -but now that you know, you can eat wisely and season with sense.

Stay healthy (and mildly seasoned) – Dr Zac

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Dr Zac Turner is a medical practitioner specialising in preventative health and wellness. He has four health/medical degrees – Bachelor of Medicine/Bachelor of Surgery at the University of Sydney, Bachelor of Nursing at Central Queensland University, and Bachelor of Biomedical Science at the University of the Sunshine Coast. He is a registrar for the Australian College of Rural and Remote Medicine, and is completing a PhD in Biomedical Engineering (UNSW). Dr Zac is the medical director for his own holistic wellness medical clinics throughout Australia, Concierge Doctors.

Originally published as Why some spices could be doing more harm than good to your health