There were not many science books available back in the 1620s. Copernicus had already published his On the Revolution of the Heavenly Spheres in 1543, but Galileo’s Dialogue Concerning the Two Chief World Systems would not appear until 1632, and Newton would not lay the foundations for modern physics with his theory of gravity in Principia for another six decades. However, Martin Blochwich, a young German physician, made a lasting mark with his Anatomia Sambuci, or in English, The Anatomy of the Elder, a 300-page tome dedicated to a single plant, the elderberry. The botanical name of this plant is Sambucus nigra, with “nigra” being Latin for black, since the berries of the elderberry shrub have a deep blue-black colour.
In remarkable detail, Blochwich described the botany of the plant as well as the various oils, syrups, ointments, juice and wine that could be produced from its berries. The most appealing part of the book was a discussion of the ailments these preparations were supposed to be able to treat. Most of these treatments, such as for tuberculosis, stomach problems, tumours and toothache, were based on folklore rather than fact, but as it eventually turned out, elderberry extracts may have some merit when it comes to such infectious diseases as influenza and the common cold.
In 1995, Israeli researchers carried out a placebo-controlled double-blind study that demonstrated significantly faster resolution of symptoms of influenza with a standardized elderberry extract. This was further corroborated by another such trial in Norway, this time treating 60 influenza patients with 15 ml elderberry syrup or placebo four times a day for five days. Symptoms were relieved four days earlier in the treatment group. Then in 2016, a placebo-controlled trial investigated colds in air travellers, since the frequency of infection in this group is known to be higher due to confinement in an aircraft. The placebo group participants had a significantly longer duration of cold episode days.
Exactly how elderberries deliver the goods isn’t clear, but researchers have speculated that flavonoids in extracts stimulate the immune system by enhancing the production of cytokines, special proteins that cells involved in immune reactions use for communication. There is also some evidence that elderberry extracts interfere with the activity of hemagglutinin, a protein found on the surface of the influenza virus that binds it to the cell that is being infected. This suggests that elderberry preparations may be able to prevent infection if taken before exposure to the virus and can also keep the virus from spreading if taken after infection has occurred, thereby reducing the duration of symptoms.
Unfortunately, “natural health products” are poorly regulated and in many cases, ingredients are mystical. There are numerous elderberry products available, and due to a lack of information about their composition, evaluation of potential efficacy is difficult. However, most studies that have documented positive results have used a standardized, proprietary extract that goes by the commercial name of Sambucol, originally developed by Israeli virologist Madeleine Mumcuoglu.
While commercially available standardized elderberry extracts such as Sambucol are safe, the same cannot be said for home preparations. The elderberry plant produces sambunigrin, a “cyanogenic glycoside” that can liberate cyanide when digested. Not enough to be lethal, but enough to cause nausea, vomiting, abdominal cramps and weakness. It is found mostly in the leaves, stem and roots of the plant, but also occurs in small amounts in the seeds of the berries. If the berries are cooked, as is the case for syrups, there is no concern because any cyanide that forms will be released into the air as hydrogen cyanide. However, if elderberry juice is made by just crushing the berries without taking care to remove leaves and twigs, there can be problems. Back in 1983, eight people in California had to be hospitalized after drinking a juice made from wild elderberries and other parts of the plant that they had gathered. All recovered within a few days. Had the concoction been heated, the problems could have been avoided.
A Columbia University professor who teaches a class on contemporary civilization learned about elderberry toxicity the hard way. By her own account, she is a “great believer in natural this and that,” and instead of taking a flu shot, she relied on a tincture she concocted from elderberries that she had grown to protect herself from infection by the flu virus. She became ill and ended up sending an email to her students explaining why she had to cancel class. Again, had she heated her brew, there would have been no issue. Would it have protected her from the flu? There just isn’t enough evidence to say.
For protection, the flu vaccine is a far better bet, but should the flu or a cold strike, there is evidence that Sambucol can be of help in relieving symptoms. In any case, the Columbia professor hopefully learned the important lesson that “natural” does not equal “safe.” Her university offers some excellent courses in chemistry. Maybe she should enrol.
Joe Schwarcz is director of McGill University’s Office for Science & Society (mcgill.ca/oss). He hosts The Dr. Joe Show on CJAD Radio 800 AM every Sunday from 3 to 4 p.m.