Survival of the Sickest Part 2

What did you think of the reading?

Dr. Moalem continues to capture me with his writing style that I have grown to enjoy very much. Like his first two chapters, the next two were just as good, if not better. To this point, Survival of the Sickest has made me ponder over topics of science I have never researched too deep into. His facts about vitamin D in chapter 3 and facts about fava beans in chapter 4 are truly interesting. Dr. Moalem still approaches these chapters through an evolutionary standpoint which makes his explanations very different and intriguing.

What did you learn?

Chapter 3 was mainly about cholesterol, vitamin D, skin, and much more. I learned that the connection between cholesterol and sunlight is important for the conversion into vitamin D. We receive vitamin D from the sun; however too much or too little can be a bad thing. Too much sun can lead to cancer, but too little can lead to a vitamin D deficiency. The fact about being more prone to sunburn while wearing sunglasses was interesting. Cholesterol, although beneficial, can be harmful if too much is present. I learned how different origins have specific diseases common to them. For example, people of African descent have a gene that causes more production of cholesterol. People originating from Northern Europe have pale skin have a tendency for Type 1 diabetes and have more of a chance for iron loading. Then, Asians are much more likely to have difficulty in processing alcohol. Dr. Moalem seems to say that these differences are due to position on earth.

In Chapter 4, the main points are about plant’s defense mechanisms and fava beans. An adaptation of poisoning from a plant was the Tapoica which contains high amounts of cyanide during drought. This allows it to protect itself from predators. A study talked about by Dr. Moalem concluded that humans have evolved the ability to taste bitterness in order to avoid toxins in plants and avoid eating them. Also, I thought that the capsaicin characteristics, that of being sticky and causing a burning sensation, in habanero peppers was interesting. The parts about fava beans captured my interest. I learned that the reason fava beans are cultivated, especially by populations vulnerable to malaria, is because fava bean consumption makes people less hospitable to malaria parasites; however, it can cause the deadly disease of favism. The genetic mutation that passes favism is passed only on the X chromosome. Favism is an inherited enzyme deficiency that is carried by 400 million people.  So while fava beans can protect you against malaria, they can bring harm later through favism. This continues the show how evolution has found ways for us to survive in the present but not in the future.

What questions do you still have?

I enjoyed reading chapter 3 and 4 because it explained a topic I never have thought over. It left me pondering over some questions. For instance reading over the part of the unique diseases due to different origins made me wonder about the diseases. Could there be diseases added or eliminated in these specific areas due to a change in the environment? Also, is it possible for humans to adapt to toxins in plants, instead of avoiding them? Is there any other instance where the cultivation of a plant or seed has helped fight against a disease? Finally, regarding fava beans, could fava beans be genetically mutated to still fight against malaria but not cause favism?


3 thoughts on “Survival of the Sickest Part 2

  1. I don’t believe fava beans themselves fight against malaria, but rather the gene that causes favism also gives a degree of immunity to malaria.

  2. The idea about fava beans is interesting and out there, but eating fava beans doesn’t fight malaria. I also learned a lot about Vitamin D that I didn’t know before.

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