Pyrrolizidine Alkaloids in Food

Pyrrolizidine alkaloids (PA) are undesirable in food. Why is that and who needs to be particularly careful?

The essentials in brief:

• Pyrrolizidine alkaloids (PA) are substances produced by plants. So they occur in nature.
• Certain PAs can damage the liver. Animal experiments have also shown that PA can change the genetic material in the cells and trigger the development of cancer cells.
• They unintentionally get into food, for example through weeds that are also harvested. This is especially the case with tea, herbs and salad. PAs have also been found in honey and food supplements.
• Large amounts of PA are particularly dangerous for children, pregnant women and breastfeeding women. People who eat large amounts of foods containing PA also need to be careful.
• Since December 2020 there have been legal maximum levels for PA in certain teas, herbs and dietary supplements in the EU, which will apply from July 1, 2022.

What are pyrrolizidine alkaloids?

Pyrrolizidine alkaloids (PA) are substances produced by plants. So they occur in nature. Plants form the protective substances so that they are not eaten by animals. However, plants that form PA are usually not used directly as food, but rather grow as weeds between the plants that are actually cultivated, such as herbs or lettuce. Especially when harvesting is done automatically with machines, these are often harvested at the same time. Sorting out is sometimes difficult when the weed looks similar to the actual crop. Ragwort, for example, looks very similar to arugula.

What foods are they found in?

The pyrrolizidine alkaloids (PA) get into tea, spices and salad through the co-harvesting of weeds. In order to be able to assess the risk that plants containing PA pose to consumers, the Federal Institute for Risk Assessment (BFR) regularly measures the levels of PA in food. Current measurements have shown that high levels of PA are found in rocket, aromatic herbs, bee pollen, rooibos tea and herbal tea in particular. When it comes to herbs, high levels of PA have been found in borage, cumin, oregano and lovage in particular. High levels of PA were also found in bee pollen. When bees collect this pollen, the pyrrolizidine alkaloids get into the honey.

Compared to the years 2011 to 2015, however, the levels of PA in most foods have decreased. Both the mean levels of PA in the foods examined and the very high levels are now much lower. The amounts of PA contained in green tea, black tea, peppermint, camomile, herbal and rooibos tea have fallen sharply. However, the measured levels of PA in spices are still very high.

Food supplements made from pollen or plants containing pyrrolizidine alkaloids, such as borage or water lavender, can also contain pyrrolizidine alkaloids (PA).

How much PA is contained in plants depends on many factors. On the one hand, different plants contain different amounts of PA. On the other hand, the amounts of PA in different parts of the plant (such as roots or leaves) can vary.

Are they dangerous?

It is not the pyrrolizidine alkaloids themselves that are harmful, but their breakdown products in the liver. Certain PAs can thus damage the liver. Animal experiments with rats have shown that PA can also change the genetic material in the cells and trigger the development of cancer cells. It is assumed that PA can also have this effect in the human body.

The BFR has examined the amounts of PA that are usually ingested in Germany. To do this, it used the measurement data of the PA in food and data on the average consumption of different foods. Based on its estimate, the BFR assesses the amounts of PA that most children and adults consume through food as harmless. However, herbs and dietary supplements were not included in this estimate. Thus, the absorbed amounts of PA from food can be significantly higher for some people. There can therefore be a health risk, especially for people who eat large amounts of food containing PA over a longer period of time, as well as for children, breastfeeding women and pregnant women.

Are there legal limits?

The general recommendation in the European Union (EU) is to consume as few substances as possible that are mutagenic and carcinogenic. Because even small amounts of such substances can be dangerous to your health if you take them over a longer period of time. This also applies to PA.

In December 2020, legal maximum levels for pyrrolizidine alkaloids (PA) in certain teas, herbs and food supplements were set for the first time in the EU. The limits apply from July 1, 2022.

What can consumers do?

Consumers who drink tea frequently or a lot should not only drink herbal or rooibos tea, but consciously alternate with other drinks. It also makes sense to alternate between different types of tea and manufacturers. Organic products are no better, since the PA is a natural ingredient in plants and can therefore also be found in organic products. Parents in particular are recommended not only to offer their children herbal tea, but also other drinks such as mineral water or thin fruit juice spritzers. Babies should be given boiled tap water or mineral water labeled “suitable for preparing baby food” to drink. Pregnant and breastfeeding women should also take care to drink herbal tea and tea alternately with other drinks.

In order to avoid consuming PA-containing plants with the salad, consumers should take care when washing and preparing lettuce to sort out plants that look foreign. You should only collect wild herbs if you are very familiar with them. This is because plants that contain pyrrolizidine alkaloids can be harvested unintentionally.