Grapefruit can possibly help. Image: Wikipedia
If cancer patients regularly drink a glass of grapefruit juice, they may be able to reduce their doses of medication and thus the side effects. This is what the results of a study by American researchers suggest. The effect of the active substance sirolimus remained the same when the patients consumed only one third of the dose and drank a glass of grapefruit juice each day. The active ingredient sirolimus is actually taken to prevent rejection after organ transplantation. However, he is also considered a candidate for the treatment of certain types of cancer, since he can inhibit the growth of tumors, at least according to initial studies. Whether the active ingredient is supported by grapefruit juice has now been investigated by a team of scientists headed by Ezra Cohen of the University of Chicago. The idea behind this is that sirolimus is partially broken down in the intestine by enzymes, so that not the entire dose actually taken can actually be used by the body. Grapefruit juice or its concentrate, however, is able to inhibit exactly the responsible enzymes. A combination of drug and juice should therefore reduce the necessary drug dose, according to the researchers.

Cohen and his team studied 138 patients with cancer who had no conventional treatment options in their study. For this so-called Phase I study, which tests the efficacy and tolerability of therapy in a few subjects, they divided the participants into three groups: one received only sirolimus, a second sirolimus and grapefruit juice, and the last sirolimus and ketoconazole. Ketoconazole is an active ingredient used against fungal infections, especially in people with immunodeficiencies or autoimmune diseases. He was used in the study because he also inhibits the intestinal enzymes that degrade the sirolimus.

First, the ideal dose was determined for each patient, that is, the amount at which the greatest effect with the fewest side effects occurred. Then the different groups were compared. Result: Subjects who consumed eight ounces of grapefruit juice a day - just over 0.2 liters - but took only about one-third of the optimal dose of sirolimus had 350 percent more of the drug in their blood than if they were the normal amount took the drug and drank no juice. The effect was the same. Those patients who ingested additional ketoconazole even had 500 percent more sirolimus in their blood, even if they were only about one-seventh of the optimal dose? however, there were many side effects in these subjects.

While there was no ultimate cure for any of the cancer patients, there was no worsening of disease in 30 percent of patients during the study period, so no further tumor growth. One of the patients was particularly prominent in the study: in his case, the tumors shrank significantly and did not continue to grow for more than three years. According to the researchers, the effect of grapefruit varies from person to person, since different amounts of sirolimus are also broken down in the patients, depending on the intestinal flora. However, before one can give general recommendations on the consumption of grapefruit juice, it would be necessary to investigate even more intensively what the effects of the interaction between the juice and the active substance really are, according to the researchers. display

Ezra Cohen et al .: Clinical Cancer Research doi: 10.1158 / 1078-0432.CCR-12-0110 © science.de - Gesa Seidel

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