Tuesday, April 1, 2014

Evolutionary Medicine: Darwin's Heel

Today [8]

It is a sunny 75 degrees outside, however the only things I can think about right now are Tylenol, Nyquil and my bed. Despite having a plethora of things to achieve today, my body decided to call it quits for the day, closing up my throat in between hoicks of phlegm while plaguing me with a headache and a desire for unnecessary sleep. I would tell you just how hot I am, but at the risk of sounding like a 65 year old chain smoker I will leave it to the thermometer. Oh great, it says 100.8 degrees. Now I have a fever, too? While these may be the common symptoms of the flu, my body may just be trying to tell me something…

Darwinian Medicine

Is this what we have become? [5]
We live in a busy and sometimes stressful world; therefore it is not surprising that any time we feel even slightly under the weather, we immediately attempt to treat the symptoms so that we may be able to return to our day to day lives as quickly as possible. No harm, no foul, right? Well it as it turns out…not always. Evolutionary medicine (also termed Darwinian medicine) is a relatively new medical practice that looks to our evolutionary history for answers to questions such as; why and how do we get certain maladies? and how can we help to prevent illnesses in the first place [1]? An interesting example given by Dr. Marlene Zuk in Riddled with Life is the ever-increasing problem of obesity. Zuk argues that we are chemically designed to keep on weight due to the chemical leptin. When stores are low, the mind tricks the body into thinking that it is starving and hence triggers hunger and immediately begins to store fat. Furthermore, our bodies may crave foods that are high in calorie content not because of flawed self-restraint, but rather as an evolutionary adaption to efficiently gain energy from as little food as possible. In a hunter-gatherer society where food was scarce and starvation a real threat, it makes sense that the body would need a backup plan for storing fat, and not one for shaving it off [1,2].

Why Am I so Hot?

Dipsosaurus dorsalis [6]
Looking at the process of natural selection to help explain the relationship between the body and disease (rather than seeing disease as a threat to an otherwise flawless body) allows physicians to infer when the body’s response to an illness may in fact be beneficial and not a side effect caused by the pathogen itself. Most people instinctively know that the fever is an indicator that something is wrong with the body. However, proponents of evolutionary medicine argue that getting a fever is the body’s response to infection, and that it may actually increase the production of cytokines to increase immunity [1]. Studies by the University of Michigan reveal that the lizard Dipsosaurus dorsalis is an ectotherm that actively seeks the hotter areas of a room when infected with sodium salicylate. What is even more astounding is that the lizards that were exposed to higher temperatures recovered faster from infection [3]. Though we are endotherms who produce our own heat and do not rely on external sources to warm our bodies up, these results can indeed be transferred to mammals as we do not change our behavior but our metabolism to overcome illness. Taking medication to reduce a fever can therefore put you at risk of silencing a helpful mechanism and therefore having a slower recovery.

What About the Other Symptoms?

Limit the spread of influenza by covering your mouth [7]
It is most important when applying evolutionary medicine to ask whether the symptom is the body’s defense or the pathogen’s offence. For example, the respiratory tract is lined with mucus that traps dirt and pollen. When the body recognizes an unusually high dose of pathogen, the body responds by producing extra mucus to prevent the invader from entering the body. If too much is produced and not expelled, the airways are stimulated and a cough results, expelling the excess mucus from the airways and keeping the lungs safe from contact [4]. However, coughing releases infected particles in the mucus and saliva which increases spread of the pathogen to other victims. Friend or Foe? While a tingling throat and fever may be annoying pre-cursors of the flu, we must realize that the cost of responding to a false positive is far less than the cost of not responding to a false negative [1]. This means that at any sign of an intruder, the body is ready for attack because it does not want to risk holding fire in case of ambush attack. So how do we know whether to treat symptoms or not? Essentially, the goal of evolutionary medicine is to discover without a doubt where the symptoms are coming from. As for me, I am going to make myself a cup of tea and crawl back in to bed.


[1] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1071402/
[2] Zuk, M. Riddled with Life: Friendly Worms, Ladybug Sex, and the Parasites That Make Us Who We Are. Orlando: Harvest, 2008. Print.
[3] http://jp.physoc.org/content/279/1/187.full.pdf
[4] http://www.adclinic.com/2012/04/cough-causes-and-tips/#.UztAtsJOXmQ
[5] www.zmescience.com
[6] www.wildherps.com
[7] http://www.theguardian.com/society/2010/dec/23/flu-surge-doctors-virus-children
[8] acurlygirlallthedaysofmylife.blogspot.com


  1. You did an excellent job with this discussion! One thing that I really enjoyed was your mentioning how Dr. Marlene Zuk, in "Riddled with Life", discussed how quickly we tend to reach for medication rather than allowing our body to utilize its defenses naturally. This reading was very timely, because as an aspiring pharmacist and having worked with pharmacists, people are getting more and more leery of the effects of medication. As often seen on commercials and as discussed in the reading, people often use medication to target one symptom and it leads to the development of other complications. Zuk does a good job of also mentioning how the first sign of fever shouldn't lead us to automatically take medication to make us more comfortable. Often just a little rest and a cold towel can help get the body back into equilibrium. I think the provided information helps us realize that we often try to help our bodies when in reality our help isn't always needed.

  2. Under the section, Why Am I so Hot, you discussed how Dipsosaurus dorsalis purposely travels to hotter regions when it is infected with sodium salicylate. While animals and reptiles alike raise their body temperature to respond to infection, how do you prevent your body from overreacting to an infection. With many infections, the pathogen may cause some problems with the host but the true problem comes from your bodies immune response. One example is of malaria. The body raises its body temperature to extreme levels to fight off the infection which can actually cause more harm than Plasmodium would by itself. How do you know when medicine is good and when it is not?

  3. First of all, I hope you feel better soon Kate! Second, you did a great job explaining the modern day issues with most of society's responses to colds. From modern day research, it is not only important to allow your body to fight off infections, but it is also important to keep your body as healthy as possible in order to increase the effective response to a sickness or a cold. Yes, our bodies will experience cold's, but it is also important to provide our bodies with the proper equipment to be able to fight off these colds. By taking recommended steps, we can also lesson these experiences from occurring, by building our immune systems. Before reading about the Darwinian medicine concept, I thought taking tons of medicines would be effective when I would get sick, and with allergy season vastly approaching, I might take a different look as to how I approach my body when I begin to experience allergy symptoms.

  4. This topic has made me think so much about all of the medicines doctors quickly prescribe to simply get us out of the office happy. I was reading an article in The Telegraph about how in today's society prescription drugs are causing more harm than good. Given, shutting down a fever and managing a daily illness are two different scenarios, it made me question how much we resort to medicine to make us feel better. I also began to think is there a possible difference in overall healing time when on medicines vs. not on medicines. Will the body simply keep working hard to fight the illness as long as we supply it with enough rest, even if it means us missing out on things? The Darwinian medicine concept is something so new to me, and yet so applicable to daily life.

    Link to article: http://www.telegraph.co.uk/men/active/10372133/Prescription-drugs-are-they-doing-you-more-harm-than-good.html

  5. I enjoyed reading your post. It was interesting, easy to follow along and relatable. This topic has been a highly discussed topic recently and people are changing their views on it. We as humans are always looking for ways to get over the annoyance of being sick, but we may really be better off without the medications we take. We do not like to endure the symptoms of the flu or any sickness and so we take medications to fix that for the time being, but we also need to pay attention to what is good for our bodies in the long term. Medications may not only affect our immune systems ability but can also be hard on other things such as our kidneys. I think that it would be right for people to take medications when they severely need them but for smaller things that you mentioned like the cough or an itchy throat we should let our bodies run their course.

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  7. I found your post quite relatable as I rub my itchy eyes and feel a little feverish. Although you are facing cold symptoms, you mentioned less pressuring side-effects of physiological responses, especially fevers. Our body can respond to fevers through antigens, such as pollen, with similar types of inflammation. As inflammation increases, core body temperature increases similarly to a cold/fever. In these types of reactions, the use of OTC medications can provide temporary relief. Severe allergic reactions can be treated with immunosuppressive steroids; however, these medications can cause damage, including impaired immunological responses to pathogens and loss of bone density. The big difference between fever and allergy symptoms, however, is having to take medication for allergies beforehand to prevent any symptoms. For a fever, Zuk mentions that it is best that we not take medication right away, but rather wait and see if our bodies can fix themselves.

  8. As I read this post I couldn't help think of the Greek word "pharmakon" (what "pharmacy" came from) which is directly translated as "drug" but can mean both "remedy" and "poison". I think this translation/meaning speaks volumes about the way patients are treated in the modern world. In the age of technology, where everyone has WebMD on their phones and is convinced that a headache and runny nose will lead to surely fatal cancer, doctors are pressured to distribute medicines to patients that don't necessarily need them. Personally, I've known health care professionals that have admitted to prescribing unnecessary medicines (usually antibiotics) to a patient just to make the patient happy. Maybe they should just print out a couple chapters of Riddled With Life (instead of magazines) and keep them in the waiting rooms of doctor's offices!

  9. Loved your post!! The part discussing why the body has a tendency to keep on fat and increase appetite when it thinks its being starved was especially interesting to me. I found this point interesting because it has occurred to me that usually the more active I am the hungrier I feel all the time. For me this isn't much of an issue because I am so active I maintain the same weight. But it did make me realize that for those who are trying to loose weight it could be extremely difficult to counteract the body's natural response to dieting and exercise. It makes clear sense why so many pole struggle to curb their appetite because in a sense it is almost fighting or evolutionary history to not eat all the food that we can when we can. Hopefully evolution catches up to the ready available food supply rather than the limited one that was available to our ancestors.

  10. Kate, this was such an easy post to follow, yet extremely educational. I enjoyed reading it! I agree that fevers are a good sign in healthy people. There are times when a fever does more damage than it does good. In cases where people have a cardiac arrest, fevers are not seen as a good thing but more of a burden. In a scientific journal article titled "Prevalence and effect of fever on outcome following resuscitation from cardiac arrest," patients who had a fever when recovering from a cardiac arrest were less likely to survive than those who did not develop a fever. This is an extreme example of a fever being a bad thing, but it only seems to be a bad thing when the body is completely worn out.

  11. Great succinct post. I do think that this is an interesting take on medical theory. We see preemptive over reactions everywhere, with mothers afraid their children have contracted some terribly virulent form of West Nile while playing in their backyards, when in reality its nothing more than a common cold. I wonder though, how can the difference between symptoms that are caused by the pathogen or the bodies defense, be differentiated. A fever is a fever. A cough is a cough.
    Besides that, I did find the section about the bodies' tendency to store fat as a mechanism to increase survival. I wonder if this could ever plague the animal world. And now that I think about, fat little puppies are becoming a bit too common place. Oh, and while this isn't "peer reviewed or anything" http://www.menshealth.co.uk/lose-weight/burn-fat/short-circuit-fat-storage

  12. Very intriguing post. I see lots of connections back to the "Hygiene Hypothesis," with us trying to foresee and forestall any possible ailments, instead of letting nature continue as it did with our ancestors. I think that it's great that we have responses to a large number of dangerous diseases, but I also agree with you that we should take time to determine whether the fever we have is an annoying symptom that we should rush to eliminate or a useful immune response that we should let run its course.
    And that's another connection I can see, the benefits of heat in your post along with the benefit of spicy food in Washida's post.