Despite a lot of vitamin C, it is not always a healthy choice: bitter substances in grapefruit can affect the effectiveness of some medications Photo: picture alliance/dpa/dpa-tmn
From BZ/dpa
Not on a full or empty stomach, not too early and not too late: if you take medication, you often have to pay attention to a few things. Also: Better to avoid certain foods.
Grapefruit is high in vitamin C and minerals like potassium, calcium, and magnesium. But if you are taking medication, the sweet and bitter citrus fruit is often anything but healthy.
Because the bitter substances in the grapefruit can impair the effect of enzymes – and thus the breakdown of active ingredients in the liver. The result: The active level in the body increases and overdose can occur, according to Prof. Petra Thürmann, Director of the Philipp Klee Institute for Clinical Pharmacology at the Helios University Hospital in Wuppertal.
This applies in particular to calcium channel blockers, which are used to treat high blood pressure, and the asthma drug theophylline.
Not too much liquorice for high blood pressure
With some drugs, such as immunosuppressants, the effect of more than half a liter of grapefruit juice is even increased so much that kidney damage can occur.
By the way: Grapefruits are not the only treat that you should better avoid with some medications. Larger amounts of liquorice can counteract the effects of antihypertensives.
Dairy products do not mix well with some antibiotics. Especially with active ingredients from the group of tetracyclines, the calcium contained in them can prevent absorption in the body.
And caffeinated pick-me-ups like Coffee and cola in combination with some medications (e.g. fluoroquinolones) lead to restlessness and make the heart race.