Grapefruit bad news for diabetics

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Grapefruit juice can be bad for people on a certain diabetes medication, a pharmacologist from the University of KwaZulu-Natal has discovered.

Dr Peter Owira's research found that patients with type 2 diabetes who are taking the medication metformin (Bigsens, Forminal, Glucophage) are at risk of developing high lactic acid levels, considered dangerous for the body.

Grapefruit juice is a popular choice among type 2 diabetics because it improves glycaemic control and helps patients reduce weight.

However, tests on three groups of rats found that although the combination of metformin and grapefruit juice lowered blood glucose levels, it also increased lactic acid levels.

Endurance athletes usually experience this as painful cramps, but it can lead to perspiration, fevers, and even death, warned Owira, whose research focuses on the molecular pharmacology of natural products.

"Dr Owira cautions such patients against consuming the fruit while on the medication metformin," said the university.

Owira said the study did not concentrate on what a safe window period would be for consuming grapefruit juice while on the medication.

(Sapa, October 2009)

Read more: Fruit juice blocks drug absorption

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