April 29, 2010
I was already planning on doing an article this week on the misconception that anything “natural” must be safe (and conversely something that isn’t natural must be harmful) when this news story broke: “alternative medicine” practitioner and promoter of “natural” remedies Gary Null is suing the manufacturer of one of his own dubious health supplements, claiming it nearly killed him because they put too much vitamin D in it (despite the fact that Null regularly recommends vitamin mega-dosing – the irony is almost overwhelming). But vitamin D is natural and good for you – how can it have almost killed him?
Any toxicologist learns pretty quickly that the “dose makes the poison” (generally attributed to Paracelsus, the father of toxicology), and that pretty much everything is toxic at some dose, even if beneficial at lower doses – much of the work of a toxicologist involves determining at just what dose a substance may have harmful effects.
These rules apply to natural substances as well as synthetic chemicals, and in fact a natural substance is just as likely to be toxic as a synthetic chemical. The most toxic substance known (i.e. the substance that requires the smallest dose to be lethal) is botulinum toxin, which is a natural substance produced by the bacteria Clostridium botulinum. Interestingly, despite being so toxic, it also apparently has some therapeutic uses, as well as being the key ingredient of botox, at even lower doses. Other “natural” substances include lead, arsenic, cyanide, benzene and benzo(a)pyrene (pretty much the “classic” carcinogen). Read the rest of this entry »
April 21, 2010
With spring rolling in and people turning their attention to gardens (at least here in the Great White North – further south I imagine people hit their gardens earlier), now seems like a good time to talk about pesticides and the efforts by a lot of groups and municipalities to ban them.
Should pesticides be banned, either totally or for cosmetic uses? Personally, I think that a “yes or no” answer is far too simplistic. The term “pesticide” refers to a very wide range of products with different chemical compositions, different uses, and different toxicity to humans and animals. They include herbicides for dealing with plants, insecticides (and insect repellents), fungicides and rodenticides. They range from naturally occurring chemicals such as pyrethrins (from chrysanthemum flowers) to modern synthetic chemicals. Obviously it is important to ensure that human health is protected, including those using the pesticides, as well as others in the community who may potentially be exposed. It is also worthwhile to protect the environment, including unintended receptors (e.g. local wildlife) and nearby water bodies. Can we do this and still allow the use of pesticides? Read the rest of this entry »
April 14, 2010
In celebration of “Homeopathy Awareness Week”, various science bloggers are doing their part to raise awareness about what homeopathy really is (e.g. here, here and here); this probably isn’t really what homeopaths had in mind. I thought I’d join in the fun. Read the rest of this entry »
April 11, 2010
A while back there was a lot of discussion going on about animal rights activists threatening not only researchers that conducted animal testing, but even their children. A lot of the discussion has been related to animal testing for medical science, where there’s a strong case to be made for it. Animal testing for cosmetics is perhaps another issue though, since strictly speaking cosmetics aren’t as important as medical advances (at least not to me). It is possible to develop new cosmetics without animal testing though?
Cosmetics (and other products applied to skin) generally need to be tested to determine whether they are corrosive and whether they cause irritation. Traditionally this has been done using what is called a Draize test, which basically involves shaving a small area of skin on an animal (usually an albino rabbit) and applying a small amount of the substance to the skin for a specified amount of time. The animal is then observed for several days afterward for evidence of effects such as redness of the skin (erythema) or fluid accumulation (oedema). Read the rest of this entry »
April 7, 2010
The Cancer Advocacy Coalition of Canada is calling for the provinces to make smoking in cars illegal if there are children in the car. Much as I hate “nanny state” laws, they have a solid case. While everyone is exposed to a variety of toxic substances all the time, when it comes to deliberately causing exposure you have to look at risks vs. benefits (e.g. cars emit pollution, but have some benefit to society). In this case, we know that second-hand smoke concentrations in a car are higher than in a smoky bar, even with the windows down, and that second-hand tobacco smoke contains numerous known carcinogens and can cause irreversible damage after as little as half an hour of exposure, so there’s definitely a risk. On the benefit side, there is nothing. If you’re an adult and choose to expose yourself to the risk, that’s your choice. As soon as you expose someone else to the risk, that’s a different story.
Here in Alberta, the provincial government is saying they have to “respect the rights of the smoking public.” To me, the rights of the children far outweigh the so-called rights of the smokers in this case. I’d like to think smoking in cars with children could be stopped or significantly reduced through education rather than laws, but experience with things like cell phones while driving leads me to suspect it won’t work.
April 7, 2010
A nice takedown of Andrew Wakefield (I won’t honour him with the doctor title, which he’s probably going to lose anyhow) by Orac. People are finally waking up to what he’s about – but a lot of damage has already been done.
April 4, 2010
Now that the “normal” flu season is over, it seems like a good time to look back on the H1N1 influenza outbreak that first came to the public’s attention about a year ago. I’ve heard a lot of people talk about how it was all media hype and no big deal – was that the case? We’re in a position now where we can look back on the outbreak somewhat objectively.
One of the first things most people seem to look at is the number of deaths. In fact, the main argument I hear for the outbreak being overblown is that the number of deaths was pretty small. As of the end of March, the number of laboratory-confirmed H1N1 deaths in Canada was 428, with 8677 hospitalizations and 1473 ICU admissions (Public Health Agency of Canada). This only includes people who were actually tested for H1N1 though, and likely significantly underestimates the actual number. US data (from CDC) suggest approximately 12,000 dead, 265,000 hospitalizations and 59 million total cases. This compares to a previous estimate of 36,000 killed in the US each year from influenza (also from CDC). It is important to note that the estimated annual influenza deaths are not based on actual data on lab-confirmed cases, but rather on the number of death certificates listing respiratory or circulatory disease and statistical modelling, so you can’t really compare these estimates to the H1N1 lab-confirmed cases. However, it seems reasonable to take the position that H1N1 doesn’t seem to have killed more people (at least in Canada and the US) than typical seasonal influenza, and may even have killed less.
I don’t think the number of deaths is really the whole story though. When you dig into the data a bit deeper, a few anomalies appear. In particular, where the 2009 H1N1 outbreak appears to be very different from seasonal influenza is in who it affects. Read the rest of this entry »