Is marmalade a health risk?

If you happen to be in the Lake District this weekend, you may want to drop into Dalemain Gardens, near Penrith, for its annual marmalade celebration. Or then again, you may not.

Started only a few years ago, the  “World’s Original Marmalade Awards & Festival” has rapidly grown. Last year some 2,000 jars of marmalade were entered in the various award categories and the event raised more than £23,000 for healthcare charities.

Most British marmalades are prepared from the Seville or bitter orange (Citrus × aurantium), which is normally only available to the marmaladier in January and February (hence the March date for the celebration).

Marmalade is centuries old, but was originally made with the bitter fruit of the quince. It is not clear when oranges were first used, but the historical collection at Dalemain House includes a manuscript book from the 1680s that includes a recipe for “a Marmalade of Oranges”.

The bitter orange has no role in orthodox medicine, but the herbal medicine industry markets bitter orange extracts as “dietary supplements” purported to act as weight-loss aids. Low-grade evidence does suggest a modest effect but, like most dietary supplements, these products  have undergone no formal safety testing. And some worrying case reports have linked them to adverse events such as stroke, angina, myocardial infarction and ischaemic colitis.

Like grapefruit, bitter orange contains p-synephrine and similar compounds that can interact with a range of drugs such as statins, budesonide, calcium-­channel blockers, cytotoxics and immunosuppressants. In most cases these citrus fruits raise the level of the drug in the blood, thus increasing the risk of side effects or even altering the drug’s intended effect.

If you take any of these drugs, the odd spoonful of marmalade smeared on your breakfast toast probably presents an insignificant risk compared with a large glass of grapefruit juice. But if, like Paddington Bear, you are an obsessive marmaladophile, you should perhaps be cautious about how much you consume.