Natural is naturally dangerous – Why the plant's own poisons are underestimated
Many believe that natural foods are safer than those with synthetic pesticides. But plants produce their own poisons – and these are often just as risky. While artificial residues are regulated, natural defences are largely ignored. A fallacy, as scientist Bruce Ames shows.
Friday, February 7, 2025
In his widely acclaimed 1990 study ‘Dietary Pesticides (99.99% All Natural)’, Ames shows that 99.99% of the pesticides in our food are of natural origin. Plants protect themselves by producing chemical defences against insects and microorganisms. These substances are found in vegetables, fruits and spices – in other words, in foods that are considered particularly healthy. However, studies show that half of these natural pesticides have a carcinogenic effect in animal testing. The same applies to synthetic pesticides, although these are strictly regulated.
Double standards in risk assessment
While synthetic residues regularly make the headlines, natural plant toxins are rarely discussed. A cup of coffee contains more known carcinogens than the amount of pesticide residues that would be ingested from other foods during an entire year. Nevertheless, coffee is not considered dangerous – a contradiction that Ames and other researchers criticise. Many consumers' environmental and health awareness is also based on this distorted perception.
It's not fear that counts, it's science
In an interview with Virginia Postrel (‘Of Mice and Men’), Ames emphasises that the debate about cancer prevention should focus on the essentials. More important than scaremongering about pesticide residues is a healthy diet with plenty of fruit and vegetables. It has been scientifically proven that a balanced diet reduces the risk of cancer – regardless of whether the food contains small amounts of synthetic or natural pesticides.
If you really want to live a healthier life, you should not rely on ‘organic’ as a guarantee of safety, but on fact-based decisions. The question is not whether pesticides – whether natural or synthetic – are harmful, but how we can use scientific progress to reduce real health risks.
The underestimated danger of plant toxins
So-called phytotoxins can be dangerous for humans. In order to assess the potential danger of phytotoxins in Switzerland, researchers at Agroscope, the federal centre of excellence for agricultural research, are investigating which plant-based toxins are present in our waterways.
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