Chemophobia

Lance Kennedy (May 1, 2019)

Recently, I was in conversation with a couple of people here in Tutukaka. The topic was the local tourist map which I produce and pay for with a series of small advertisements. I was asking them to advertise their business. One of them said she was not happy to do so since the tourist map was not environmentally friendly. My eyebrows went up, and I pointed out that the map was on card board, which was biodegradable. She agreed, but said her problem was the ink which was full of chemicals. Again, my eyebrows went up, and I suggested that everything was full of chemicals, including the human body. She disagreed vociferously. Only synthetic evil products contained chemicals.

This is not unusual. Plenty of people have a horror of chemicals, which they believe are always synthetic materials, shockingly toxic, and cause terrible harm both to human health and to the natural environment. Of course, they also believe that nothing natural is toxic, or can cause environmental damage. Why do people think this way?

What does the science say? Strangely, the most toxic chemicals ever discovered have all been of natural origin. The worst of the lot is a mixture of eight different proteins made by a bacterium, Clostridium botulinum, which is a nerve poison that paralyzes muscle cells. It is so toxic that, if one tenth of one millionth of gram is injected into a man, he has a 50% chance of dying from it. This horrible substance also called Botox and is injected routinely into people as part of cosmetic surgery. How is it that no one dies? The reason is because each injection is only one quarter of one billionth of a gram. By comparison, the worst man-made substance is one of the dioxin family (2,3,7,8 TCDD). We do not know how toxic it is to people, since, for some strange reason, researchers seem reluctant to poison human subjects, but based on animal studies, it seems to be about 1,000 times less toxic than Botox.

The science of poisons is called toxicology, and the most basic principle in this science is that it is all about the dose. Botox injections do not kill because the dose is far too small to cause any serious harm. But the opposite applies. Everything becomes toxic when the dose is big enough. Did you know, for example, that anyone who drinks six litres of water over three hours may be killed by it? And this has happened. Did you know that oxygen becomes lethal if breathed under high pressure? I do because I scuba dive, and this is a known hazard. The most toxic substances are benign at low dose, and the most benign substances are toxic at high dose.

Exactly the same principle applies to the impact of any chemical substance on the natural environment. Low dose means no problem. High dose, even for an otherwise innocuous material means serious damage. For example, the Great Barrier Reef is suffering harm from soil, mainly from sugar plantations, washed into the ocean, smothering delicate corals. A high dose of innocuous soil becomes a destroyer of ecosystems.

What about a low dose of something very toxic. The uranium 235 radioisotope is generally considered to be environmentally toxic, but there are about 50 million tonnes of it dissolved in sea water, and they do no harm. Why not? Because this is a dose of only about one part per hundred billion in sea water. Much too low to be harmful.

Everything solid, liquid or gas, is made of chemicals, and how harmful they are depends mainly on the dose.

Another time, I was visiting a plant nursery to buy some young fruit trees. A woman walked past, trailed by a gaggle of disciples, delivering a lecture on organic gardening. To my disgust, she referred to conventional food by asking them if they wanted to go on eating poison all their lives. Since that time, I have learned more about organic farming, and have come to the conclusion that it is mostly just another superstition. Certainly, conventional food is not poison. Not only that, but the British Food Standards Agency commissioned a study comparing organic and conventional food and found no measurable difference between them in terms of impact on health.

The truth is that synthetic pesticide residues, which organic food enthusiasts are paranoid about, are present in such low dose as to be insignificant. There is another truth, ignored by such people. All plants produce toxins, often concentrated in green leaves, to prevent insects chewing on those leaves. These toxins are present in human food at levels that average 10,000 times the dose of synthetic pesticide residues. Those natural pesticides are far more toxic, gram for gram, than modern synthetic pesticides. For example, potatoes contain an alkaloid called solanine, which is roughly the same toxicity as sodium cyanide. The only reason we can eat potatoes is that the dose of solanine in the white parts (but not the green) is very, very low.

To make matters worse for the organics enthusiasts, the plant toxins are produced in higher amounts when the plant is actually attacked by insects. Since organic, unsprayed crops get attacked more, organic food ends up with a lot more toxin than conventional. Back in 2002, eleven people here in New Zealand were hospitalized with cucurbitacin poisoning, from eating unsprayed zucchinis. A case of organic food proving more toxic than that terrible conventional food with its synthetic pesticide residues. So, in spite of what that woman said, eating organic food results in more consumption of poison than eating conventional. What should we fear in food? In fact, it is not poisons in tiny quantities we should we concerned about, but major components in large doses. Sugar, salt, saturated fat, transfats, and purified starch.

So maybe it is cancer we need to fear? The well-known scientist, Professor Bruce Ames spent a lifetime studying the relationship between ingesting toxins and cancer risk. He discovered that half of all chemicals caused cancer when ingested in high dose. For example, plain old cabbage contains about 120 easily extracted chemicals. When tested, roughly 60 of them were found to be carcinogenic at high dose. Does this mean we should not eat cabbage? No, of course not. Cabbage is an excellent and healthy food. Those 60 carcinogens are present in quantities too low to be of concern. For cancer, the principle is the same. It is all about dose. So the next time you hear a chemical being indicted as being cancer causing, ask about the dose.

Last year, a law suit in the USA attacked Monsanto corporation for selling the herbicide glyphosate. A groundsman who had used glyphosate spray for many years came down with terminal non Hodgkins lymphoma. He blamed it on the glyphosate and sued. The initial jury verdict was to award $289 million, mostly punitive damages. Of course, juries do not do science.

So, what does the science say? Science, unlike juries, does not blame the chemical for being manufactured by a large corporation. And the bulk of scientific studies show it to be benign. It is non mutagenic and has no effect on human DNA.

There are more than 500 good studies showing no harm. However, many substances can cause cancer at high dose. A study on laboratory mice showed that if they are fed glyphosate at a dose much higher than any human would ingest, for 85% of their life span, it can cause cancer. This was sufficient for the jury, though no scientist would accept such spurious evidence.

This is an excellent example of how ordinary people can come to fear benign substances. As skeptics, we can help to educate people so that they make more rational decisions.