Herbs and dietary supplements can seriously interact with medications. People who have to take medications should pay close attention even to what they eat – warns Dr. Katarzyna Wolnicka from the Food and Nutrition Institute in Warsaw.
– OBOP research shows that in the last 12 months, 22 percent. Poles used at least one dietary supplement. Of these people, 29 percent of the respondents used them every day or almost every day throughout the year. Not many people are aware, however, that dietary supplements can interfere with the action of pharmaceuticals, causing a health hazard, warns Dr. Wolnicka.
He adds that adverse interactions often occur between synthetic drugs and various plant ingredients.
He mentions St. John’s wort as an example, which may reduce the effect of hormonal contraceptives used by women. This can result in irregular bleeding and sometimes even an unwanted pregnancy.
Tincture or tea of St. John’s wort, one of the most popular herbs often used to relieve stress or to help you sleep, may also worsen the effectiveness of digoxin, a digitalis medicine used to treat heart failure.
– Herbs and dietary supplements, as well as some nutrients, reduce or increase the concentration of many drugs in the blood, sometimes even multiple times – explains Dr. Wolnicka.
In her opinion, worse absorption of drugs is mainly caused by laxative herbs, which increase intestinal peristalsis. Such action is demonstrated by: aloe vera, buckthorn root, senna leaf and fruit, and rooting root, often used in slimming herbal mixtures.
Other medicinal plants, such as flax, marshmallow and plantain, contain the so-called Locks (a viscous, gelatinous solution of organic substances that reduce the access of the drug to the intestinal mucosa – PAP).
Licorice should not be used along with hormone replacement therapy. Dr. Wolnicka warns that it contains phytoestrogens that may increase the effects of hormonal drugs, causing nausea, migraines, swelling and irritability of the breasts. In combination with contraceptives, it causes hypertension and hypokalaemia (too low serum potassium concentration below 3,6 mmol / L in adults – PAP).
Licorice is especially dangerous in people taking diuretics (used, for example, in the treatment of high blood pressure), as it increases the excretion of potassium ions by the kidneys. Signs of this are weakness, painful muscle contractions and abnormal heart rhythms.
You should also be careful with rhubarb (palmar flushing), which increases the excretion of potassium from the body.
Many herbs should be discontinued before undergoing surgery. Garlic (or preparations containing it) must be stopped one week in advance, as it increases bleeding and may impair wound healing. Ginkgo works in a similar way, but it is enough to give it up 36 hours before the procedure.
Ginseng increases the bleeding and causes hypoglycemia, a drop in blood glucose levels. You have to stop taking it a week before the procedure. On the other hand, valerian, used as a mild sedative and aid to falling asleep, prolongs the effects of anesthesia. – You should not just discontinue it abruptly, because it causes symptoms of abstinence – warns Dr. Wolnicka.
Food can also cause serious drug interactions. Products containing high amounts of fiber reduce the effects of digitalis and tricyclic antidepressants (such as amitriptyline) because they worsen their absorption in the gastrointestinal tract.
Dr. Wolnicka gives an example of grapefruit juice, which slows down the metabolism of antihistamines, i.e. antiallergic drugs (reducing the secretion of substances that contribute to hypersensitivity – PAP). The result is an increase in its concentration by as much as 300-700 percent. and heart rhythm disturbances.
Grapefruit juice also causes multiple increases in blood levels of statins, blood cholesterol-lowering drugs such as lovastatin, simvastatin and atorvastatin.
People taking bisphosphonates – drugs for osteoporosis, should not eat foods, especially those rich in calcium, such as milk and dairy products, for 2 hours after taking them. You should also refrain from consuming vitamins with microelements and antacids, argues Dr. Wolnicka.
In her opinion, calcium can negatively affect the action of the so-called calcium channel blockers used to treat high blood pressure. It also worsens the absorption of beta blockers, one of the most important drugs in cardiology, used e.g. in heart failure.
Zbigniew Wojtasiński
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