Flowers in food ‘give rise to health concern’

By Katy Askew contact

- Last updated on GMT

More data is needed to establish 'safe' consumption levels for flowers in food ©iStock
More data is needed to establish 'safe' consumption levels for flowers in food ©iStock
The use of edible or wild flowers in food is growing in popularity but a lack of chemical and toxicological data and presence of toxic compounds in some species could be causes for concern, Danish researchers suggest.

In recent years, Danish restaurants, food producers and consumers have become increasingly interested in the use of both wild and cultivated flowers in cookery. However, according to the National Food Institute at the Technical University of Denmark, there is not necessarily a history of using these plants in foods either in Denmark or internationally.

The National Food Institute is therefore assisting the Danish Veterinary and Food Administration to complete a risk assessment of 50 plants that the food safety authority has identified as part of a control campaign among restaurants and local food producers. In 23 cases, the National Food Institute found flowers from these plants were used in food production.

The National Food Institute researchers then completed a review of “available knowledge”​ on potentially toxic compounds in the 23 flowers, descriptions of poisonings or other toxic effects in humans and animals following consumption, and evidence of their traditional use as food in Europe.

Long-term exposure may be damaging 

According to this research, 13 of the 23 flowers contain substances that could have harmful effects.

Mikael Mandrup Egebjerg, a researcher at the Division for Risk Assessment and Nutrition at the National Food Institute, told FoodNavigator that while consumption levels may be low, the risks of long-term exposure were a potential cause for concern.

“Our task was to flag the lack of safety data of these popular plants, which may be in contrast to common beliefs,” E​gebjerg explained.

The researchers found most of the toxins present in the flowers do not make people acutely ill, but may be damaging in the long term. Some of the identified substances are known to be carcinogenic or may cause cardiovascular disease, while others may damage the nervous or reproductive systems, they suggested. 

Yarrow for example contains the neurotoxin thujone, which is also found in absinthe and the alcoholic drink absinthe. There is also evidence that high doses of yarrow flowers have an effect on the testicular tissue in mice and rats—an effect that must be caused by substances other than thujone. 

Meanwhile, borage and viper’s bugloss contain pyrrolizidine alkaloids, which may cause liver damage after longer exposure and are suspected carcinogens

“Regarding consumption of flowers, the dose would arguably be small, so we do not expect a high risk of acute toxic effects. However, some of the investigated flowers contain compounds that are considered genotoxic carcinogens, for example pyrrolizidine alkaloids in borage,”​ Egebjerg noted.

“These compounds are unwanted in food commodities may cause cancer even in small amount if consumed over longer periods of time.”

The “sparse data”​ available on the toxic substances contained in the 13 plants flagged by the study meant the researchers were not able to set a limit for safe consumption of the flowers. And while there is no evidence that the remaining ten flowers contain toxins, “very few​” chemical studies of these flowers have been carried out. As such, the researchers have also been unable to set a limit for safe consumption of these flowers.

Not ‘traditional’ in Europe

Under the novel food legislation, all plants that have not traditionally been used as food must be approved for consumption before they can be used commercially in food.

Denmark’s Veterinary and Food Administration has therefore asked the researchers for information on whether the flowers have been used as food in the EU prior to 1997, when the regulation came into effect.

For most flowers, the researchers have not found evidence in the literature that they have traditionally been used in cooking before this date.

Source: Food and Chemical Toxicology

Published online: October 2018

DOI: 10.1016/j.fct.2018.07.007

'Are wild and cultivated flowers served in restaurants or sold by local producers in Denmark safe for the consumer?'

Authors: Mikael M.Egebjerg, Pelle T.Olesen, Folmer D.Eriksen, GitteRavn-Haren, Lea Bredsdorff, Kirsten Pilegaard

Related topics: Science, Food Safety & Quality, Food safety

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