Exemestane, often prescribed as Aromasin®, is a type of hormonal therapy known as an aromatase inhibitor used to treat breast cancer in postmenopausal women. It works by blocking the enzyme aromatase, which helps produce estrogen, thereby reducing the amount of estrogen in the body and hindering the growth of hormone-sensitive breast cancer cells. To ensure the medication works as intended and to minimize side effects, paying close attention to your diet is essential. While many foods are safe, certain items can interfere with how your body processes exemestane.
The Dangers of Grapefruit and Related Fruits
One of the most widely known and serious food-drug interactions involves grapefruit. This is not specific to exemestane but applies to many medications metabolized by the CYP3A4 enzyme in the small intestine, which grapefruit can block.
How grapefruit affects exemestane
Grapefruit contains organic compounds called furanocoumarins, which inhibit the CYP3A4 enzyme. When this enzyme is blocked, it can lead to higher-than-intended levels of the drug entering your bloodstream. This effectively gives you a higher dose of the medication than prescribed, increasing the risk of more severe side effects.
Which fruits to avoid
- Grapefruit and grapefruit juice
- Seville or bitter oranges (often used in marmalade)
- Pomelos
- Starfruit
- Pomegranate
The Impact of High-Fat Meals
Exemestane is typically recommended to be taken with or after food to help with absorption and reduce mild nausea. However, the type of meal you have can be a factor. Some sources indicate that taking the medication with a high-fat meal can significantly increase the levels of exemestane in your blood.
Managing your meal timing
It's best to take your daily dose after a regular, balanced meal rather than a particularly heavy or greasy one. This helps ensure consistent absorption without the risk of over-absorption associated with high-fat intake. For example, a light dinner is a better choice than a fatty fast-food meal right before taking your medication.
Restricting Alcohol and Caffeine Intake
While moderate alcohol consumption is often considered safe with exemestane, excessive drinking can be problematic for several reasons. Furthermore, caffeine and spicy foods are often linked to a common side effect of exemestane, hot flashes.
Alcohol's role in side effects
Heavy alcohol use can worsen fatigue and drowsiness, which are already common side effects of exemestane. Some sources also suggest that excessive alcohol may decrease the medication's overall efficacy. To help manage side effects and maintain the medication's effectiveness, it is wise to limit or avoid alcohol completely during treatment.
Caffeine and hot flashes
For those who experience hot flashes, caffeine and spicy foods are known triggers that can make symptoms worse. Opting for decaffeinated options and milder foods can help reduce the frequency and intensity of these episodes.
Avoiding Herbal Supplements and Phytoestrogens
Some herbal supplements can contain phytoestrogens, which are plant-based compounds that mimic the body's natural estrogen. Since exemestane works by lowering estrogen levels, introducing these estrogen-mimicking compounds can counteract the medication's therapeutic effect.
Counteracting the medication
It is crucial to be transparent with your healthcare provider about all herbal products and supplements you are taking. Supplements containing St. John's Wort are particularly noted for potentially altering blood levels of exemestane and should be avoided. Other herbs with phytoestrogenic effects, such as flaxseed supplements (not small amounts in food), red clover, and ginseng, should also be discussed with your doctor.
Comparison of Risky vs. Recommended Foods
| Food Category | Avoid/Limit During Exemestane Treatment | Recommended for Optimal Health During Treatment |
|---|---|---|
| Citrus & Related Fruits | Grapefruit, pomelo, starfruit, Seville oranges, pomegranate | Oranges, lemons, and other non-problematic citrus fruits |
| Meals | High-fat, greasy, or heavy meals | Balanced, regular meals with moderate fat content |
| Beverages | Excessive alcohol, excessive caffeine, sugary drinks | Water, herbal teas, decaffeinated coffee |
| Herbal Supplements | St. John's Wort, soy protein supplements, concentrated flaxseed, black cohosh, red clover | Only supplements approved by your oncology team |
| Spicy Foods | Chili, curry, wasabi, hot sauces (can worsen hot flashes) | Mildly seasoned dishes, fresh herbs |
Conclusion
Managing your diet carefully while on exemestane is a proactive step toward ensuring your treatment is as effective and tolerable as possible. The primary concerns involve fruits that disrupt drug metabolism and foods that exacerbate common side effects. Avoiding grapefruit and high-fat meals is critical for maintaining proper drug levels, while limiting alcohol, caffeine, and spicy foods can help manage symptoms like hot flashes and fatigue. Always communicate openly with your oncology team about your diet and any supplements you take. They can provide personalized recommendations and help you navigate your nutritional needs throughout your treatment. For more general information on dietary management during aromatase inhibitor treatment, you can review resources like the Food for Breast Cancer website.
Resources
- Food and drink to avoid during cancer treatment - Cancer Research UK
- Foods To Eat & Avoid During Aromatase Inhibitor Treatment - Food for Breast Cancer
- Exemestane (Aromasin®) - OncoLink
