Two cases of anticholinergic syndrome associated with consumption of bitter lupin flour

upins (Lupinus spp) are legumes, otherwise known as pulses. There are about 450 Lupinus species, with L. angustifolius and L. albus being the main species cultivated in Australia. While lupins have been predominantly used for animal feed, recent research has shown that eating them can provide health benefits for humans. The addition of sweet lupin flour to bread has been shown to reduce its glycaemic index, reduce energy intake and increase satiety of study participants compared with those who consumed standard white bread. The addition of sweet lupin flour to sausages was shown to decrease fat intake and increase satiety in study participants when compared with those who consumed full-fat sausages. Adverse consequences of eating lupins can be divided into toxic and allergic reactions. Studies have identified both serological and clinical cross-reactivity between peanut and lupin, although lupin allergy can also occur without allergy to other legumes. Lupins are separated into sweet varieties, which have an alkaloid content of approximately 130–150 mg/kg, and bitter varieties, which need to undergo a debittering process to remove potent alkaloids before consumption (these are left with an alkaloid content of approximately 500 mg/kg after debittering). The debittering process involves soaking beans in repeated changes of water. The alkaloids leach from the beans into the water, which is then discarded. Solvents can also be used for debittering. Failure to remove, or incomplete removal of, alkaloids can result in lupin toxicity, manifesting as anticholinergic syndrome. Anticholinergic syndrome can also be caused by various drugs, including some antihistamines, antipsychotics, antispasmodics and antidepressants, as well as by eating some mushrooms and plants.8,9 Plants known to cause anticholinergic syndrome when ingested include Datura spp (jimson weed, angel’s trumpet), Salvia divinorum (diviner’s sage), Atropa belladonna (deadly nightshade), Hyoscyamus niger (black henbane) and Mandragora officinarum (mandrake). Fatal cases of lupin poisoning have been reported, with the lethal dose calculated as about 30 mg/kg bodyweight. Bitter lupins are commonly eaten by people of Mediterranean origin, and these traditional users are aware of the need to debitter the lupins before consumption. There are relatively few published reports of acute lupin toxicity overseas, and only one in Australia, which involved a Mediterranean woman who had eaten lupin beans that had not been sufficiently debittered. In light of the increasing consumption of lupin products, we recommend that information be provided to food suppliers and Clinical records