Safety of Nigella Damascena Seeds
Answered by: Conrad Richter
Question from: Elise Durocher
Posted on: April 04, 2008

Dans votre catalogue on mentionne que les graines de Nigella damascena sont semblables au cumin noir et comestibles. Toutefois j’ai trouvé sur 2 sites web différents (Wikipedia.com et Krissnature.net) que les graines de la nigelle de Damas contient des alcaloides toxiques. Je suis un peu perturbée. Qui dois-je croire?

Fleurs et Délices dont je suis la propriétaire est une entreprise de culture et transformation de fleurs comestibles. Je me suis fier à vous pour dire à mes clients qu’ils peuvent consommer les graines de cette magnifique fleur. Pouvez- vous me rassurer? Sinon, pouvez-vous ajouter un rectificatif dans votre prochain catalogue avec une mise en garde que les graines contiennent des alcaloides qui peuvent être toxiques en grande quantité et ne doivent pas être confondues avec la Nigella sativa laquelle est comestible.

Vous comprendrez que la santé de mes clients me tient à coeur et je ne voudrais pas les malinformer.

According to the Plants for a Future database (http://www.ibiblio.org/pfaf/cgi-bin/arr_html?Nigella+damascena&CAN=LATIND) the seeds of Nigella damascena, or love-in-the-mist, have a nutmeg flavour and have been used as a condiment, both cooked and raw. This is based on four references to the plant’s traditional use as a seasoning, including Sturtevant’s 19th century Edible Plants of the World (http://www.swsbm.com/Ephemera/Sturtevants_Edible_Plants.pdf). Sturtevant called the plant "wild fennel" and wrote "[t]his species is grown in Turkey for its seeds which are used as a condiment." The PFAF database does not mention of any risk of ingesting the seeds due to the seeds’ alkaloid content. According to Herbapedia (available from Richters) the seeds contain saponin, an essential oil, and an alkaloid called damascenine. According to the U.S. National Library of Medicine Mesh database, damascenine is an "odiferous principle of oil of Nigella" from the seeds of N. damascena (and N. arvensis). According to other sources damascenine is responsible for the pleasant scent and flavour of the seeds. But damascenine does not show up in Jim Duke’s Phytochemical database, and the U.S. government’s PubMed database did not have any recent abstracts, so the significance of the herb to human health is difficult to access.

I checked the Wikipedia entry on Nigella damascena but I did not see any mention of toxic alkaloids, so I am not sure where you read about this. The Wikipedia entry on the related species, Nigella sativa, the Asian spice known variously as onion seeds, black caraway, black cumin and kalonji, refers to a study in the PubMed database which links the biological activity of Nigella sativa seeds to thymoquinone, a component of the essential oil. The authors go on to write that Nigella sativa seeds are "characterized by a very low degree of toxicity" (http://www.ncbi.nlm.nih.gov/pubmed/12722128?dopt=Abstract).

I also checked the entry on Nigella damascena at krissnature.net (http://krissnature.over-blog.com/article-13394665.html) and there it does claim that the seeds "contain a toxic alkaloid" but doesn’t identify the alkaloid or give any further details or any references.

Another online source characterized the toxicity of Nigella damascena seeds as "very high", causing "vomit[ing], headache, diarrhea, convulsions, icterus, liver injuries, weakness, coma and death" (!) (http://www.botanical-online.com/alcaloidesaranuelaangles.htm). There is no indication what quantities are required in order to induce these effects. I could not substantiate these claims as the source gives no references to any toxicity studies, nor could I find any other reports with similar claims.

So how do we resolve the apparent contradictions here, that the traditional use of the seeds as a condiment suggests that the seeds are safe while a few reports are suggesting that the seeds are toxic? My personal take is heavily influenced by the simple fact that traditional food and herb knowledge is a distillation of generations of practical experience. A food would not be adopted by humans if it caused harm. Even if harm is subtle, harmful foods would be dropped in favour of less harmful foods eventually, and that knowledge of which plants to avoid and which to eat will be transmitted from generation to generation. We know this to be true because there are examples of plants with high apparent food value that were never adopted as foods because they have turned out to be subtly harmful. Typically these subtly harmful plants are at most used as famine foods, only to be ignored in times of plenty.

Just as there is something to be said about the enduring truth of traditional food knowledge, there is cause to question some of the findings of modern science. A particularly insiduous leap of logic is to rely on what is known about pure compounds and use that to impute the risks of plants with low levels of those compounds in the leaves, stems, roots or fruits. Like falling through a trapdoor, once a herb is found to contain a harmful substance, even if the levels are insignificant to human health, that herb falls into a sort of herbal dungeon and rarely ever gets back out. The remediation of herbs once labelled dangerous almost never happens. Who has the money to conduct the studies needed to disprove a theoretical claim of harm? I wouldn’t be surprised that that is what happened here with Nigella damascena because I could not find any animal studies or reports of human adverse reactions that support the claims that Nigella damascena is toxic.

Poppy seeds, by the same logic, should be banned because they contain low levels of opium, and taken in large quantities (as a tea) they can be addictive just like opium. Fortunately for millions of bagel and pastry lovers poppy seeds have never been banned. But if animal studies or adverse reaction reports show that regular use of poppy seeds -- or regular use of Nigella damascena seeds -- is dangerous, then we must not ignore the evidence.

Still, one can never know for sure where the truth about safety really lies, and each of us must in the end make a personal decision whether any food, vegetable or herb is safe to use.

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