Steve Jobs was not only an inspirational business leader and genius, he was also a fan of organic and whole food and even raw food. In fact the name Apple came from his interest in eating fruit. So it is a bit against the script of the common idea of healthy eating that he should die prematurely of cancer. Events like this call out for an explanation. Can we find one?
For many years I was under the impression that pesticide residues in food were likely to be carcinogenic. Many pesticides have at least the potential to be endocrine disrupters, mimicking hormones like estrogen in our bodies to trigger off undesirable changes. It is not too difficult to conceive that they might have a carcinogenic effect. (For more background see my blog post on chemophobia). It seemed to me that the cost imposed on society as a whole by slightly increased cancer rates was one that was worth paying for cheaper and more readily available fresh food. It was years before I investigated properly and found out that although pesticides certainly make a big contribution to cheaper food and making it possible for us to enjoy plenty of fresh fruit and vegetables, it turns out that there is no evidence of any increased cancer risk after all. So that was good news, though I have to confess that I resisted the notion for quite a while. Somehow a long held wrong opinion feels a lot more comfortable than one backed up by the facts.
Changing my mind about the risks of conventional food is a bit more than academic, because I have to decide what to eat. Supermarkets offer a choice between organic and conventional food. I appreciate the choice and I have always chosen to mix what I eat. I quite deliberately select some organic and and some non-organic. That way I diluted down the pesticide residues and supported the organic sector. But I also kept my food bills down by participating in the benefits of efficiently produced vegetables as well. I was quite pleased with myself for this. Not many people have a food purchasing strategy and even fewer have a well thought out one, so it made me feel rather special.
I haven’t actually changed this habit, though I don’t feel quite as smug about it any more. I still think that having an organic option, and I still think it should be small compared to the conventional one so I’ll stick with it for now. Interestingly, even now over half a century since the movement started, nobody has been able to show any health benefit to organic food. But there is more to the question of how we grow our food than just cancer rates. I’ll leave that discussion for another day.
So having realised that eating organic food wasn’t going to decrease my likelihood of getting cancer I thought about it all a bit more. Cancer rates in industrial countries overall are declining, and as far as I can tell nobody really knows why. One possibility is simply that we are eating better. The combination of pesticides and fertilisers that are used in modern agriculture along with excellent transport means we can all eat good quality fresh food all year round. It might not be organic, but it still contains plenty of nutrients that our bodies need, and which might well help our bodies to keep healthy. This seems to fit well enough. But is there a bit more to it than that even?
I am really grateful for Tina S who drew my attention to this paper, http://cei.org/PDFs/hormone_factory.pdf, in the comments on my post about shampoo making you fat. It points out that plants are more than capable of producing endocrine disrupting molecules including estrogen mimics. In fact it is quite a regular thing for them to do, as has been known since the 1930s. As always it is the dose that makes the poison – so it isn’t necessarily something to worry about. As I found with synthetic pesticides, the small amount we get from eating food is simply too low to do any harm. But are the levels of endocrine disruptors produced by our food crops just as insignificant? We don’t know. And there are some indications that maybe it is not something to be complacent about.
There are continual problems with infertile sheep in australia as a result of eating particular species of clover. As part of the investigation into this rats and rabbits were fed soybean oil, which contains the estrogenic compound genisten. They exhibited reproductive disorders as a result. It has also been found that sugar beets produce secondary metabolites that kill off flies once they are attacked. So there is a demonstration of direct link between insect attacks and the production of harmful chemicals. If evolution can produce this effect once, it could have done so again.
Is it possible that the use of pesticides has depressed our plant crops’ production of dangerous carcinogenic metabolites? And could it therefore be the case that the fall in cancer rates is the result of this? It seems a bit far fetched. I don’t think that there is yet anywhere near enough evidence to take it as anything more than a suggestion. In that respect, it is a bit like the possible risk from parabens. Both are good stories and don’t violate any laws of nature or statistical probabilities, but both seem a bit far fetched and don’t have much in the way of supporting data. But the idea that conventionally grown crops are less likely to contain naturally produced carcinogens does seem worth investigating.
Would Steve Jobs still be around if he hadn’t been so keen on organic food? We’ll never know the answer to that, but I do wonder.
This paper looks at the effect of naturally occurring genisten, an estrogen mimic found in soybean oil on mice.
This paper describes how estrogen mimics are produced by desert plants under drought conditions, which limits the fertility of the quails that eat them.
Refined vegetable oils don’t show any estrogenic effects.