Carcinogens in natural foods - the Ames test

I have previously written about the difference between natural foods and "unnatural foods" in terms of how much carcinogens they contain. I did one post on "Irrational fear of pesticides", and another post that I called "natural foods contain more carcinogens than unnatural foods".

Just now I found a video clip from Physics for Future Presidents, a UC Berkeley lecture series that you can watch for free online, in which Richard Muller, an entertaining physicist explains what this is all about. Watch and enjoy.

Dangers of radiation in the home

The best Swedish site for news on technology, in my opinion, is www.idg.se. Today they have an article on radiation in the home. The article is based on an interview with Maria Feychting professor in epidemiology at Karolinska Institutet. The article discusses the danger of the radiation associated with products that are becomming increasingly common in ordinary homes. I am speaking of mobile phones, routers, wireless keyboards and mice, bluetooth headsets and dect phones.

The conclusion of the article, briefly put, is that there are no scientific evidence that this radiation causes any harm. It is a fact that studies showing potential dangers of radiation get much more attention than studies which show zero effects, even though the latter type are much more common. Furthermore, most of the studies which have shown slight biological effects of radiation have subsequently been replicated with contrasting results i.e. the latter studies did not find any effects.

I think that one of the reasons why some people are so afraid of these things is the fact that they radiate, and we all know that radiation is bad right? No, not necessarily so. Radiation can be your friend to. If it were not for the radiation from the sun we would not be alive. Similarly, seeing involves the capture of radiation by photoreceptors in the back of your retina. In fact we are all rich sources of radiation which you can see for yourself if you have a camera that pick up infrared wavelength.


But isn't that different? Sure some sorts of radiation are more dangerous than others. Cosmic rays which arive from outer space are extremely rich in energy, and alot of that type of radiation would be bad for you. Similarly, X-rays will slightly increase the risk of cancers because it is rich in energy. But what about the radiation from all those home devices? This radiation is lower in energy than normal visual light, so you are very unlikely to get cancer from this type of radiation. These devices actually emit microwaves, just like your microwave oven. The difference is that the radiation is not contained within a box, and also the power is 10,000 smaller than in an ordinary microwave oven (for a dect phone it is 100,000 times smaller). If you want a different point of view on these issues, you can visit this page.

The article also gives some quick answers to the following questions:

1. Does radiation from mobile phones cause cancer: False

2. Will using a bluetooth headset reduce the amount of radiation you are exposed to: True (because a bluetooth headset has a much lower effect than the mobile phone)

3. A dect phone emits more radiation than a mobile phone: False

4. A 3G phone radiates more than a GSM mobile phone: False

5. More wireless devices in the home will make it more dangerous: False

6. A new router radiates more than an old router: False

7. It is dangerous to have your mobile lying next to you when you are sleeping: False

8. The mobile will emit less radiation if you hold your hand over it: False (actually it will radiate more becuase that is necessary in order to communicate the station.

9. Even the good old cable hardware emits radiation: True (anything with a current in it, a cable for instance, will generate a magnetic field which is also basically a form of radiation.


I want to end with a personal reflection on an issue which I think is highly relevant yet often forgotten. Mobile phones, which as mentioned is the device which has the highest effect and thus the highest radiation, has been around for about two decades now. In spite of their popularity, there has not been any increase in cancers in this timeperiod. This "natural experiment" shows that if mobile phones have any effect at all on the human body, that effect have to be very subtle. Pretend for a moment that there has been a slight increase in some obscure form of cancer, or other type of disease, that is a result of mobile phone radiation. Even such a necessarily slight effect would pale in comparison to the enourmous benefits of being able to call ambulances, fire fighters and the police from almost anywhere on this planet. Hurray for mobile phones!

Do we have a soul?

It is easy to get lost in a discussion about the existence or nonexistence of the soul. However, quite frequently conflicts do not arise because people disagree, but rather because they are using different definitions of the soul. Depending on the definition used I either believe or do not believe in the existence of a soul. A common though not very useful definition of "the soul" is what we really are, the core of our selves, or something like that. I would perhaps be inclined to call this "personality" rather than soul, but if that is what is meant by soul then yes, I think I do have one.

If on the other hand the soul is seen as something which is necessarily immaterial, then I do not believe in it. Hypothetically, should someone make an exact replica of me, with the exact same atoms in the exact same places, nothing more would be required. The replica and I would be impossible to distinguish from each other. The replica would react to any stimuli like me, would have the same childhood memories, be attracted to the same things, and just like me the replica would be disgusted by the smell of an orange.

This would not last long though. If me and my replica would continue our lives, then gradually subtle environmental differences would form us in non-identical ways, resulting in some small differences. These differences would ultimately affect the choices of me and my replica and consequently our preference would diverge. This, in turn, would lead to escalating environmental differences and increasingly different personalities or, if you prefer, souls. The resulting differences between me and my replica would be reflected in the way our atoms are put together, so we would no longer contain the exact same atoms. Nevertheless, there would probably be many striking similarities as well. There are examples of genetically identical twins that have grown up in very different environment, and still similarities have been extremely apparent.

What do I base this belief on? My main piece of evidence is that there does not seem to be any part of the personality that cannot be affected by brain injury. In my neuropsychology course I read about many patients with exotic brain injuries. A famous patient called HM, who is still alive, is unable to form any new memories. As a result he still thinks that he is 25 years old and he does not recognize the researchers who have visited him every day for several decades. Another older case is that of Phineas Gage who got a metal stick shot up through the frontal part of the brain. To everyone's amazement Gage did not die from the injury, however, according to his colleagues he was not the same after the injury. Following the injury he started swearing and behaved inappropriately to the extent that he lost his job. However, the most striking case that I can remember only vaguely is that of a responsible normal woman with three kids. Due to a tumor in her brain she suddenly underwent a radical personality change. Her behavior went from normative to completely reckless, and from being a good and faithful wife, she became extremely uninhibited and promiscuous…

One needs merely to take a look at a severe case of Alzheimer disease to see that material changes in the brain can change a person beyond recognition. Some would say that there is always something left, that even though Anna is now eating her own feces and hitting her children when they come to visit, she is still Anna, somewhere inside. I don't think so. Sure, she is still called Anna, and one can still recognize her appearance, but other than that Anna is not Anna anymore. The soul of Anna is very different from the soul Anna used to have before she got Alzheimer.

In sum, due to the fact that there seems to be no sacred part of the personality, nothing which cannot be affected by changes of a material nature. Due to this I do not believe that we have an immaterial soul. Normally I try to avoid the word altogether because of the confusion that arises, but this is my current thoughts on this issue. The discussion here has many important implications, for instance it should affect how to think about free will vs. determinism. I have written about that here.

Irrational fear 1: Pesticides

About three months ago I wrote a post on natural foods and the highly exaggerated danger associated with pesticides. I cited research done by Bruce Ames (see picture), Professor of biochemistry and molecular biology at UC Berkeley. In this very interesting interview, Bruce Ames gives his view on organic foods. In the following excerpt from this interview Ames explains that the reason why he is against spending more resources on natural foods is not that it contains more carcinogens but rather that the production and in consequence also the products is more expensive. More expensive fruits and vegetables means less consumption which will result in more cancers:

Ames: Yes. I'm much more interested in preventing cancer. Then we have to get out to the public what's important. If you tell them about trivia all the time, they get completely confused, and it's counterproductive. I just think all this business of organic food is nonsense basically. We should be eating more fruits and vegetables, so the main way to do that is to make them cheaper. Anything that makes fruits and vegetables more expensive may increase cancer.

When I cite this information people often ask where Bruce Ames gets his money from. Is he really trustworthy? This is a fair question when you take into account the fact that the food industry is a big industry, and if organic foods would suddenly become the public choice it would certainly be rather detrimental to many companies. What many people seem to forget though is that producers of organic foods also have money waiting for them, should they manage to sway the public opinion. Unless it is suggested that organic food producers have a superior morality, immune to economic incentives, this is not a valid argument, after all the economic incentive is there for both sides. Maybe those the people who tell us that organic is the way to go do so because they would get rich if people followed their advice?

I feel quite confident that Bruce Ames is not bought by the food industry. Why? Partially, I believe Ames is a good guy because of what my intuition tells me. When I read the interview (referenced above) with this scientist he just doesn't strike me as a man who has sold his soul to the devil, quite the contrary in fact. However, the main reason why I don't think Ames is bought by the food industry is that he is also the man who first proved that many synthetic pesticides are carcinogenic. For quite a while he was a hero to all the natural food proponents.

Bruce Ames showed that indeed many man made chemicals are carcinogenic, but what reason do we have to assume that natural pesticides aren't also carcinogenic? Ames did not make this assumption and when he tested natural pesticides, which are created by the plants themselves as a protection, he found that pretty much the same proportion of natural pesticides was carcinogenic. Furthermore, Ames discovered that plants which are not treated with synthetic pesticides (i.e. natural foods) contain more potent carcinogens than plants which have been treated with pesticides. (Things can be more or less carcinogenic; for example, even though mushrooms contain 50% carcinogens they are very weak and therefore doesn't do a lot of damage whereas coffee contains much stronger carcinogens.) Read my previous post if you want to understand why. Add to this that 99.9% of the pesticides that we ingest are natural pesticides and you will understand why this post is about irrational fear.

Here we are worrying about 0.1% of the pesticides we ingest which according to the data are, if anything, less mutagenic than the other 99.9%. That is what I would call irrational fear…

”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

Should we use stem cells?

"Stem cells fend off lung cancer".

I just read a news article with this headline in the journal Science. Apparently, because stem cells are rather similar to cancer cells, the immune system adaptation that occur when you inject stem cells into the lung, will subsequently help the immune system kill cancer cells as well. That is, the immune system treats stem cells as invaders, why they develop a defense against these cells. If the same immune system, on a subsequent occasion, encounters a cancer cell it will, because of the strong resemblance, wrongly "assume" that it is another stem cell and therefore get rid of it. Out of 25 mice that were given stem cells, 20 were able to kill a subsequent cancer. A slightly altered compound increased the cancer survival rate to 100%!!! This should be compared to the 0% survival rate experienced by mice that did not get any compound.

Of course, this does not mean that we can cure cancer in humans, at least not yet. Mice for some reason tend to respond better to cancer therapies, but nevertheless, I think the figures above justifies some excitement. I think that stem cell research is one of the methods with the best potential. This research not only has the potential to cure cancer, but various other diseases and insults as well, including Parkinson disease, chronic pain, and strokes.

So what about the larger issue? Are stem cells individuals? I guess that if you believe that a cell with all the genes necessary to build a human being is an individual, then stem cell research is murder. However, if this is your belief then scratching your nose or stepping into a shower would be genocide. All the cells that die when you do one of these two things could produce an individual if you put it into an egg and allowed it to mature. So why should stem cells be protected as if they were full grown individuals? A fully conscious monkey, capable of feeling pain and stress, has barely any rights! That is puzzling to me. Furthermore I think not doing stem cell research is unethical, considering the huge potential. Not doing stem cell research is the same as saying to those who have Parkinson or those who are suffering from chronic pain, that "we care more about these few cells than we care about finding a cure for you".