Saturday, April 14, 2007

”Natural Foods” contain more carcinogens than ”Unnatural Foods”



If you are like me, the first thing you will react to in the headline is my discrimination between natural and unnatural foods. It is my impression that people who call natural foods "natural foods" refer to foods which have not been treated with pesticides. Personally I don't think this makes them more natural, and it definitely does not necessarily make them better. I suppose that natural foods are more natural in the sense that it is what we used to eat back in the days when we did not have the kind of technology that we have today, though based on that one could argue that primitive foods would be a more appropriate label. I must admit that I have never actually heard anyone talk about unnatural foods, I just assume that if someone asserts that foods which have not been treated with pesticides are natural, then they must think that foods which have been sprayed with pesticides must somehow be unnatural.


In any case, people who eat natural foods often claim that it is better for you. Why? Well according to the people I have talked to, natural foods are less toxic to you because they have not been sprayed with pesticides. Pesticides, according to these people are quite poisonous and ingesting them will result in all kinds of bad effects such as cancer. Therefore natural foods, which have not been sprayed with any pesticides must be better for you. The problem is that all foods, including natural foods, produce their own pesticides. In a moment I will argue (convincingly I hope), that natural foods in fact have a larger concentration of pesticides and that the pesticides in natural foods are even more toxic than the synthetic pesticides that we produce and spray on our "unnatural foods".


So how come natural foods have pesticides in them? If you think about it the answer is quite obvious. All plants need defenses against plant eaters. If a plant cannot avoid predation, then natural selection will take care of that plant in no time. That is, any plant without defenses will die and only the ones that do have a proper defense will be able to survive, reproduce, and thus send their genes into the next generation. Now plants are not particularly mobile, and therefore they cannot run away from their predators. So what do they do? They evolve defenses which either makes them hard to eat (e.g. thorns on cactuses), or they evolve chemical or pesticides that will either kill or hurt the predator when they try eating the plant. These substances are called natural pesticides. Natural pesticides are the chemicals contained within plants in order to make organisms that eat them sick or even kill them.


So we have two types of pesticides. There are pesticides that we produce in our industries and spray on plants to protect them from other organisms, and there are pesticides that the plants make themselves for the very same reason. What is the difference between these two types of pesticides? You may be thinking that since we have been exposed to natural pesticides (the ones the plants make) for a longer time, we would be able to handle them better, not so. The defenses we have in our body to protect us from pesticides are general, that is they don't care whether it is a natural pesticide or a synthetic pesticide, in fact they treat almost all different pesticides the same way. Throughout our evolutionary history, as we have included more things in our diet, we been exposed to new "natural pesticides". To our body the synthetic pesticides that we spray on plants are simply yet another novel pesticide. If you are still not convinced, consider the fact that there are quite a few types of pesticides that we have been exposed to for thousands and thousands of years which still today can be very bad for us.


I hope to have established that there is no general qualitative difference between the pesticides that we produce in our industries and the pesticides that plants produce. However, in all fairness this is not entirely true. The synthetic pesticides that we use today are selected based on their ability protect the plants on which they are sprayed, and importantly only mild toxins are used, that is our body can take care of them relatively easily. This means that if a plant is sprayed with synthetic pesticides that plant doesn't need to make its own pesticides because it is already protected. Of course, to the extent that the synthetic pesticide is toxic, the plant will also become more toxic, but normally this effect is very small. Now if, on the other hand, you do not spray a plant, then that plant will have to form its own pesticides, and the stronger the better. The plants that do not do this, as I mentioned before, will die. In consequence, each new generation of natural food crops will be the offspring of the most toxic plants in the previous generation. This should logically mean that the natural pesticides in natural foods are much more toxic than the natural pesticides in foods that have been sprayed.


This question has in fact been tested experimentally by Bruce Ames at the University of California, Berkeley. How did he test this? Well first, being a cruel scientist, he created a bacteria that lacked an enzyme that was critical for its survival. The only way for the bacteria to survive was if it, through random mutations got a working gene capable of producing the vital enzyme. Now, Ames would create say a thousand colonies of these unfortunate bacteria. Then he would squirt something, say a natural pesticide, on all the different colonies and see how many would grow. Ames could infer that if a bacterial colony would start growing then mutations had occurred in that colony, in other words the substance squirted on them must have been mutagenic and therefore carcinogenic. If you compare natural pesticides and synthetic pesticides in this type of test you will see that the natural pesticides will leave much more survivors than the synthetic ones. This may be good news for the bacteria, but not for us, because more mutations means higher risk of cancer. In other words the predictions stated above has been confirmed in the experiments performed by Ames.


What do I want to say with this? Well, I do not want to give the impression that I think natural foods are necessarily bad. Doing a very quick literary review I found a few studies claiming that there are more nutrients in organic relative to normal foods (organic foods is an extreme form of natural foods). However, all I want to say is that I think that our fear of synthetic pesticides is probably a little bit exaggerated, and that in many cases the toxins produced by the plants themselves are far worse.


Ps: For a good chapter on carcinogens in foods see Ames here in Handbook of toxicology

13 comments:

Anonymous said...

"What do I want to say with this? Well, I do not want to give the impression that I think natural foods are necessarily bad...However, all I want to say is that I think that our fear of synthetic pesticides is probably a little bit exaggerated, and that in many cases the toxins produced by the plants themselves are far worse"

Umm...right, science in its glory. Science as in contrary to folk belief. Science as in finding articles among other articles.

No offense, your article was quite interesting, but I have a hard time agreeing with your conclusion. You have simply not discussed the issue of pesticides and less developed countries. As you might know people in South america die young because of synthetic pesticides that are forbidden in western countries. But still the fruits themselves are being transported to us in the west..so much for synthetic pesticides on fruits being more healthy

Are the researchers you refer to, by the way, independent or hired by the food industry? I guess there might be some money to fund your research if you come to such conclusions...Ehum

And how come people living in Sweden have more problems with allergy than in many less developed countries where people eat more fresh and non-sprayed food, vegetables and fruit?

How about concentrations of pesticides in the natural versus the synthetic case? Will the apples on a tree spray ten kg of pesticide on themselves?

And so forth.

I'll go for my folk-belief. Non-sprayed natural fruit from your garden is to recommend, if such is avaible. If not, one should by food coming from companies practising ethics. In relation to people, workers, consumers and the environment.

rasmussenanders said...

Hello Anonymous,
Thanks for the comment.

Obviously, when I talk about synthetic pesticides I mean the legal ones, the ones which have been tested. If some developing countries are spraying formaldehyde on their crops that it another matter as far as I am concerned.

I don't really understand why the people in South Africa are dying if we are the ones who eat the fruits? Are they spraying the people? Why aren't we also dying if they ship the fruit here?

Bruce Ames, the scientist I have refered to, is a respected scientist working at the University of Berekeley, California, so they don't get much more independent than that.

I don't know why people in Sweden have more allergies (actually I didn't even know that they had more allergies). Is there any reason to suspect that it may be becuase of pesticides, and if so, why is the rate as high in other developed countries (Swedish people actually eat quite a lot of natural foods)?

About the concentrations of pesticides. 99.9% of the pesticides that we consume are natural pesticides. At least that is the case when we eat food which have been sprayed with pesticides. In spite of this 70% of all tests done are done on synthetic pesticides. A large assymetry in other words.

You are of course welcome to keep eating your natural foods. There are perhaps, as I mentioned briefly in my post, other factors that could be of importance. I brought this up primarily because I thought the just mentioned assymetry was very notable. Furthermore, we are loosing quite a bit in terms of production by making natural foods. Therefore I think it is important to at least see if it is any better at all...

Z said...

"I don't really understand why the people in South Africa are dying if we are the ones who eat the fruits? Are they spraying the people? Why aren't we also dying if they ship the fruit here?"

ehmmm...ok, so maybe, say, when they spray the crops from the airplanes, the air gets polluted. Maybe so bad, that they get very sick.

When i eat an apple from Argentina/Peru, i only get a tiny dose of pesticides, not having to inhale the fumes and vapour all day. Just a thought.

rasmussenanders said...

That could be an explanation I suppose. If you are given a large dose of pesticides, natural or synthetic, you will die (just like a large dose of virtually anything will kill you)

If they do indeed spray people instead of crops I really hope that they will improve their technique...

One interesting fact I just found when I did a search was that pesticides are frequently used to committ suicides.

Tanya said...

this was very helpful for my paper on organic foods. Thank you!
your blog is so fascinating. i hope to persue my education in the sciences as well and i hope to be as passionate about it as you are!
thanks for the inspiration
:)

rasmussenanders said...

Thank you for your words of acknowledgement, I do appreciate them!

Unfortunately I have not written for some time now because I have been busy, but I will continue soon

Thanks again, and good luck in the future

Anonymous said...

Please change your wording to "non-organic" rather than "Natural foods". Natural food is a total different thing...example, white flour vs. Whole wheat, white flour is process and is striped of nutrients, whole wheat is just whole wheat..."natural food".

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This comment has been removed by a blog administrator.
Pierce said...

So interesting, but are you saying that those natural pesticides that the plant produces are harmful to us?


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Kim said...

I think you might be missing the point when people say natural foods. It doesn't only refer to pesticides and what is sprayed on fruits and vegetables. They talk about the processing that takes place when producing these foods for mass markets. During those processes many of the foods are changed from what is grown or raised originally. I read this article and it made a good deal of sense. Check it out. http://www.medicalvoyce.com/articles/2010/12/natural-foods-optimal-health-0

rasmussenanders said...

To Pierce:

I am not saying that natural pesticides are very harmful, only that synthetic pesticides are not particularly harmful in the doses we get when we eat food.

I would claim though that if you had a cup of natural pesticides and a cup of synthetic pesticides then, often the cup with the natural pesicides is more dangerous.

Anonymous said...

Eating all natural foods has really helped in my weight loss journey. I think it is beneficial for your health and in keeping the weight off. I am so excited to see how much I will lose a few months from now. I have been getting my natural weight loss tips and diet reviews at www.weightnatural.com

John said...

"I hope to have established that there is no general qualitative difference between the pesticides that we produce in our industries and the pesticides that plants produce." No, you did not.

"This means that if a plant is sprayed with synthetic pesticides that plant doesn't need to make its own pesticides because it is already protected." Where is your reference here? Where is the research that shows when a plant is sprayed with synthetic pesticide it will produce less of a naturally occurring substance meant for defense?

"Ames could infer that if a bacterial colony would start growing then mutations had occurred in that colony, in other words the substance squirted on them must have been mutagenic and therefore carcinogenic." That is a pretty big inference.

The fact is our regulations should go back to the condition that a substance has to be proven safe before it may be applied to/used in food not that the FDA or other agency has to prove it is harmful. Once these substances are in us and the environment it might take years, decades or, as people are finally starting to wake up to, generations for the harmful effects to be become apparent. By that time it is too late. The damage is done. People have been sickened, killed (cancer, leukemia, anemia..), rendered handicapped (birth defects), infertile... We all incur the cost of this. whether it be the care of a destitute patient covered by tax dollars because they can no longer afford needed treatment or maybe the care (welfare) of a broken family, parentless children who have lost the "bread winner". The fall out goes on and on and on and may span decades and generations too.

The fact is these substances are produced for profit, and like anything else produced for profit, profit comes first. It starts with the profit of a company, then comes the profit of its share holders as time goes by it is the profit of the people involved in regulation... It is a vicious belief system based on attrition. Make no mistake about it capitalism/free market has moved from a tool for the improvement of lives and upward mobility to (or back to) a belief system akin to religion. Where who cares who is displaced, poisoned, maimed, killed... as long as profit is had and the collateral damage is within acceptable limits to some corporate figureheads, associated corrupt politicians... The acceptable limits are anything as long as it will not be attributed to them.

I am not a religious person but I think science and big business need to stop trying to play god. So keep this crap out of my food.