Australian research finds dietary or cooking habits affect drug dosage tolerance

Posted by AFN Staff Writers on 17th October 2011

A University of Sydney PhD student has discovered that a patient’s diet and cookery styles impacts on the required doses of medicines commonly used to treat illnesses such as depression and psychosis.

Vidya Perera, a final year PhD student in the university’s Faculty of Pharmacy, found that people from South Asia could need lower doses of these medicines because they are likely to have lower levels of CYP1A2, an enzyme that metabolises drugs.

Vegetables such as cabbages, cauliflower and broccoli are known to increase levels of CYP1A2, as was demonstrated in this study and previous studies in people of European background. Mr Perera said, “The lower levels of CYP1A2 in South Asians, however, appears to be due to the common practice of cooking these vegetables in curries using ingredients such as cumin and tumeric, ingredients known to inhibit the enzyme, overriding the effect of the vegetables.”

A total of 332 people took part in the study – 166 South Asians and 166 Europeans. CYP1A2 levels were measured by giving participants a caffeine tablet, and analysing CYP1A2 enzyme activity in saliva samples four hours later. Demographic, dietary and lifestyle information was obtained using a questionnaire.

Mr Perera said that most drugs are approved in clinical trials conducted in Europe and North America using healthy, middle-aged European men. This is the first study to look at CYP1A2 activity in South Asians.

Professor Andrew McLachlan, Associate Dean in the University of Sydney’s Faculty of Pharmacy said, “Past research has attributed differences between people from different geographical regions to result from genetic differences. This important research highlights how dietary and cultural factors can impact on pharmacological response.”