Natural v manmade chemicals

Fruit and vegetables containing toxic chemicals

Q: What do apples, pears, potatoes and zucchinis have in common? A: They all contain toxins.

Regardless of whether a chemical is made by nature or made by man, it tells us nothing about its toxicity.

Chemicals are everywhere. In the air we breathe, in the water we drink, in the pills we pop. Even the most self-sufficient humans can’t avoid consuming or coming in contact with chemicals.

Unfortunately, there is a common misconception that chemicals made naturally are harmless, whereas manmade ones can damage your health or the environment.

Yet, the fruit and vegetables in the picture* above tell another story.

Apple seeds contain amygdalin – 0.6/kg of seeds
Pears contain formaldehyde – 0.06/kg
Potatoes contain solanin – 0.2g/kg (higher in green potatoes)
Zucchinis contain cucurbitacin E – variable amounts but higher in bitter zucchinis

These fruit and vegetables contain chemicals that have been shown to be toxic to humans, however, they contain such minute quantities that they don’t cause any harmful effects. Conversely, other “natural” chemicals are lethal to humans even in very small doses – think cyanide, think arsenic. Whereas many manmade compounds are perfectly harmless to humans unless ingested at very high doses.

The take home message is: the dose makes the poison – regardless of whether the compound is natural or manmade.

The graph below provides a snapshot of natural and manmade chemicals, and how only the dose makes something poisonous.


Natural v manmade chemicalsModern living

“It is worth noting that, although it’s popular to complain about ‘all those synthetic chemicals’, this contrasts with increasing demand for them in and around the home e.g. oral contraceptives, mouthwash and decorating materials, and for gadgets which are manufactured using them, like mobile phones, computers and CDs.

Prof Andrew Cockburn
Toxicologist, University of Newcastle, UK

Fast facts about chemicals

  • Claims that proclaim products are “chemical free” are untrue. There are no alternatives to chemicals, just choices about which chemicals to use and how they are made.
  • Regardless of whether chemicals are manufactured by people, copied from nature, or extracted directly from nature, tells us nothing about how safe they are.
  • There are many misconceptions about chemicals being ‘linked’ to diseases. In reality, chemicals that show up in tests simply tell us that a chemical was present when an effect occurred, rather than showing that the chemical caused the effect.
  • Antibiotics are prepared using manmade chemicals and save more lives than any other medical intervention.

*The picture and graph courtesy of

Related Post

Esters | their role in cosmetics | skin conditioni... Esters play an important role in cosmetics as they form the backbone of many ingredients, such as perfumes and naturally occurring fats. What are est...
Prebiotics | fibre for good gut health Prebiotics are a type of soluble fibre that supports microbes beneficial to good gut health. Although a relatively new discovery -  evidence is still...
Science 101 | toxic chemical vs doses | part 2 There is no such thing as a toxic chemical, there are only toxic doses. Let me say that again: essentially all chemicals are safe at a low enough dos...
Essential Oils | where do they come from? Essential oils are found in the roots, stems, leaves and flower of a plant. After processing procedures, they form a clear liquid or a yellow to amber...