Favism is a genetic disease involving a deficiency in glucose-6-phosphate dehydrogenase (G-6-PD), an enzyme that is essential for the survival of red blood cells. This enzyme deficiency primarily affects male populations. Its frequency is relatively high in the Mediterranean, Sub-Saharan Africa, the Near and Middle East, South-East Asia and South America, as well as in the French West Indies. Due to population migration, its frequency in France (both mainland and overseas territories) is far from negligible; according to Ministry of Health data it may affect more than 250,000 people.
Most often, the G-6-PD deficiency is asymptomatic, but when substances contained in certain medicines and foods are consumed, crises may occur. In these crises, the red blood cells burst, causing sudden and severe anaemia (neonatal jaundice in the newborn or potentially lethal haemolytic anaemia at any age).
Foods to avoid
In 2006, the Agency received a formal request from the Directorate General of Health (DGS) to formulate dietary recommendations for people with this enzyme deficiency. According to the literature review conducted by the Agency, the broad bean (Vicia faba or fava bean) is the only food whose responsibility has been demonstrated in triggering haemolytic crises among people with favism. Consumption of broad beans, irrespective of their mode of preparation, should therefore be avoided.
Two other substances are also described as being the cause of haemolytic crises in patients with a G-6-PD deficiency: quinine and vitamin C.
The consumption of beverages containing quinine is therefore not recommended for these populations.
In addition, high intakes of vitamin C that could be attained by consuming enriched products or food supplements containing this vitamin, should also be avoided, as this may exceed the safety limit defined in adults for this vitamin at 1 g/day. Consumption of products naturally rich in vitamin C (fruits and vegetables) does not pose any particular problem for patients with a G-6-PD deficiency.
Raising awareness among professionals
Given the risks presented by this disease and the ignorance of them by professionals in healthcare and the food industry, it seems necessary to provide better information on the potential risks presented by broad beans, quinine and high doses of vitamin C in people with a G-6-PD deficiency.
The regulations require labelling of broad or fava bean flour if it is used as an ingredient in processed foods. However, some foods contravene this rule, especially in the bakery sector, despite an upper limit of 2% being imposed by the decree on the amount of broad bean flour likely to be incorporated into bread flour. The Agency therefore recommends cautioning professionals in this sector against the excessive use of broad beans and not exceeding the upper limit of 2% imposed by the above-mentioned decree.
In addition, the Agency has recommended the creation of an information guide describing the disease and its potential consequences, intended for catering professionals and school canteens.
Finally, the Agency stresses the need to raise awareness of this disease among health professionals, as it is indeed relatively unknown to non-specialised medical services.
The Agency recommendations have been taken into account in the guide entitled "Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency or favism - Information and advice" issued by the Ministry of Health to health professionals as part of the National Plan for Rare Diseases.