During chemotherapy treatment, it is natural to want to boost your immune system with vitamins, antioxidants, or natural products. However, it is important to remember that “natural” does not mean harmless. Some supplements can reduce the efficacy of your treatment without you realizing it, or even increase its side effects. Therefore, before starting any product, it is essential to consult with your healthcare team.
This article has been reviewed by María Elviro Lloréns, Hospital Pharmacist.
Why Can Natural Remedies Interfere with Chemotherapy?
The liver is primarily responsible for processing the medications we take, including chemotherapy. To do this, it uses enzymes such as those in the CYP450 system, which act as “tools” to metabolize drugs.
Certain medicinal plants and supplements can alter the functioning of these enzymes, increasing or decreasing the concentration of the drug in your system. This can lead to toxicity or a lack of efficacy, respectively.
If you consume a supplement or medicinal plant that uses these same “tools,” the chemotherapy can accumulate in your blood, causing toxicity, or conversely, be processed too quickly, making the treatment less effective.
The Red List: Foods and Products to Avoid (Dangerous Interactions)
It has been proven that certain foods and medicinal plants can interact with oncological treatments:
- Grapefruit: Can increase the amount of certain medications in the bloodstream.
- St. John’s Wort (Hypericum): Can drastically reduce the effectiveness of some cancer drugs.
- High-dose antioxidant vitamins (such as Vitamin C or E): In large quantities, they may interfere with the action of some treatments. They should not be taken without medical indication.
- Vitamins and immune health: If a deficiency is confirmed in a blood test, supplementation prescribed by a doctor is both safe and necessary.
- Over-the-counter (OTC) multivitamins: Without medical supervision, these are not a good idea during treatment.
- Plants such as turmeric, ginger, ginseng, or ginkgo: These should only be taken under supervision, as they can affect blood clotting, especially if platelet counts are low.
The Importance of Professional Guidance
Every treatment and every patient is different. What is safe for one person may not be for another. Before taking any supplement, vitamin, or natural product:
- Inform your oncologist or hospital pharmacist of all the products you are currently taking.
- Do not start or stop any supplements without prior consultation.
- Always report everything you are taking, even if it seems “harmless.” When in doubt, bring the packaging or a photograph to your appointment.
The safety and success of your treatment depend on professional and personalized follow-up.
