There’s a good reason why more oncology centers are taking a more holistic approach to fighting cancer. The body of research indicates that with cancer, everything matters—from your state of mind to foods that nourish your body.
A new study illustrates why the whole-person approach to cancer treatment is so important in improving treatment, and more importantly, survival.
Researchers found that drinking 8 ounces of grapefruit juice a day increased the effect of the drug Sirolimus (Rapamune) by 350%.
Early studies suggest that sirolimus may have tumor-fighting effects. Derivatives of the drug are used in kidney cancer and breast cancer.
However, one drawback of sirolimus, and the reason why it was chosen for this study, is that it has poor bioavailabilty. The body is only able to absorb about 14% of the drug when taken.
Nearly 150 patients with incurable cancer were given either sirolimus alone, sirolimus plus grapefruit juice or the drug along with ketoconazole (Nizoral), which is used to treat fungal infections.
The most effective dose of sirolimus was about 90 milligrams a week, but at doses above 45 mg there were serious side effects, such as nausea and diarrhea. Patients taking the drug alone were switched to 45 mg.
When sirolimus was given with ketoconazole, patients needed only 16 mg of sirolimus a week to achieve a drug response. Patients taking grapefruit juice needed 25 mg to 35 mg of sirolimus, the researchers noted.
Grapefruit juice increased sirolimus levels by 350% and ketoconazole increased the drug levels 500%.
While ketoconzole achieved a greater effect, the advantage of grapefruit juice over ketoconazole is that it is not toxic and carries no risk of overdose, the researchers said.
How It Works
Grapefruit juice inhibits enzymes in the intestine that break down sirolimus, making more of the drug available to the body, said study authors.
This affect on drug dosing is seen with other drugs as well. For example, patients are cautioned not to drink grapefruit juice when taking cholesterol-lowering drugs called statins. For patients, this means that they may be able to reduce drug doses which can translate to fewer side effects and lower drug costs.
When foods like grapefruit juice affect drug dosing, the challenge for researchers and clinicians is determining the “adjusted” drug dose to ensure an optimal effect, say experts.
Based on this example of how a single food can dramatically affect the effectiveness of one drug, can you imagine treating cancer—or any health condition--without considering the effects of diet and nutrition?