Plant food supplements are mostly safe

February 13/2019

Most plant food supplements are safe. Problems can be caused when plant food supplements are used simultaneously with medication, especially when using several plant food supplements or medicines. According to the new risk profile by the Finnish Food Authority’s Risk Assessment Unit, there are many uncertainties and a lack of information related to the safety of plant food supplements. The study did not examine the benefits of plant food supplements. The Finnish Food Authority does not recommend the use of plant food supplements by children or pregnant women.

The risk profile did not cover all plant food supplements. The risk profile study included 30 plants used in plant food supplements, of which nine species were studied in more detail. The most commonly used plants in food supplements were the Echinacea or coneflower, ginger and red yeast rice.

“In Finland, the use of plant food supplements is typically periodical and several preparations are used simultaneously. Supplements are also used that contain several plant species. It is also typical that doctors and pharmacists are not told about the use of plant food supplements,” says Tero Hirvonen, Senior Researcher, PhD, at the Finnish Food Authority.

Plant food supplements may involve health risks

Plant food supplements were rarely used for the treatment of diseases, with the exception of colds. No characteristic substance of plant food supplements was used in such large quantities that the dose as such would be toxic, but the use of plant food supplements together with medicines may be harmful.

”The risk profile showed that there was a significant risk of interaction with medicinal substances, particularly for users of ginger and horsetail supplements. It must be noted, however, that the combined effects of food supplements involve a great deal of uncertainty, as few studies have been carried out on humans. In addition, many users used several plant food supplements with medication, often supplements that contained several different plants. This increases the uncertainty of assessing the interaction, as there is very little knowledge about the interaction between plant food supplements,” says Hirvonen.

Red yeast rice and green tea are the most problematic

The most problematic plant food supplements to emerge from the risk profile were red yeast rice and green tea.

The use of red yeast rice supplements revealed hazards caused by the users themselves. Red yeast rice supplements were most used often contrary to instructions: the users had numerous illnesses and they also used a great many medicines.

“It seems that red yeast rice supplements are used solely for the treatment of high cholesterol, even though there are far safer means available, such as weight control, dietary changes and medication. Users of red yeast rice supplements also reported elevated liver enzyme levels, which indicates liver damage,” says Hirvonen.

Large doses of green tea supplements can also cause liver damage.

The new risk profile is based on the part of the survey data collection in the EU-funded PlantLIBRA project conducted in Finland, information obtained from literature on the composition of plant food supplements and the toxicity of the compounds they contain, as well as the possible pharmacokinetic interaction of the characteristic substances with medicinal substances.

Read the Risk profile on plant food supplements publication (description in English) (pdf).

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For more information, please contact:
Tero Hirvonen, Senior Researcher, Risk Assessment Unit
+358 295 204 264, Tue - Thur 9 a.m. to 12 p.m.