Doctors have told how a woman developed a dangerous blood clot in her leg from eating too much grapefruit for breakfast.
The case is reported in the Lancet by Dr Lucinda Grande of Providence St Peter Hospital, Olympia, Washington, USA, and colleagues.
They write that the 42-year-old woman presented to their emergency department in November 2008 with difficulty walking, shortness of breath, and light-headedness. She had pain from her lower back down to her left ankle, the left leg was purple and swollen, and she was diagnosed with acute venous thrombosis.
Emergency treatment prevented venous gangrene developing, which may have led to amputation. All the symptoms resolved and she was discharged.
“Medical history was unremarkable,” the doctors write. But “she had begun an aggressive weight-loss diet three days earlier, including 225g grapefruit every morning; previously she had eaten grapefruit rarely”.
They report that she had stenosis in the left common iliac vein, suggestive of May-Thurner syndrome. The syndrome is triggered by compression of this vein, alongside endothelial injury and hypercoagulability, which in this patient, was due to the factor V Leiden mutation and oestrogen contraceptive use.
“We hypothesise that she also had enhanced hypercoagulability as a consequence of her new diet,” they write, as grapefruit juice can inhibit an enzyme called CYP3A4. As it has a half-life of about 12 hours, “a cumulative effect of daily grapefruit juice consumption can occur”.
“Our patient had a constellation of potential risk factors for venous thrombosis; a heightened hypercoagulable state from increased ethinylestradiol serum concentration due to her three days of grapefruit for breakfast may well have tipped the balance,” they conclude.
Grande, L. A. et al. Attention – grapefruit! The Lancet, Vol. 373, April 4, 2009, p. 1222.
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