The Surprising Extent of Medical Illiteracy
Recently I have been taking courses on Bilibili - mainly junior- and senior-high-school science courses, and I chose videos by teachers with large followings. As I listened, I discovered something surprising: chemistry teachers - celebrated names, no less - were making elementary mistakes in their lectures.
One chemistry teacher, lecturing on why sharks don't get cancer, explained it very plausibly and even dug up a multiple-choice question for students to choose the correct answer. I know many people propagate the myth that sharks don't get cancer by word of mouth, but I did not expect a natural-science teacher to make such a basic error.
When I heard him say sharks don't get cancer, I even briefly doubted whether my own knowledge was sound; then I asked some friends on WeChat who study the life sciences - all medical or biology PhDs - and learned that I had not misremembered: sharks do get cancer. Every multicellular organism gets cancer. In multicellular life, apart from dead cells, any living cell can become cancerous; multicellular organisms differ only in the probability of cancer, not in whether they can get it.
Some vendors hype that sharks don't get cancer for commercial reasons; a science teacher should have the basic common sense to recognize that such hype contradicts scientific knowledge. I believe anyone who has studied high-school biology should know that multicellular organisms inevitably get cancer. As for us humans, we have tens of trillions of cells - roughly ten thousand times the population of the Earth - and it is impossible for so many cells to make absolutely no mistakes over several decades. As long as some cell errs during division or differentiation, we risk cancer.
Another chemistry teacher lectured on why ancient people rarely got cancer while modern people do: because ancients ate fewer acidic foods, their bodies were weakly alkaline, and cancer does not easily arise in a weakly alkaline environment. This shocked me; I checked the recording date - it was within the last two years.
That an acidic constitution causes cancer, an alkaline constitution does not, that eating acidic foods causes cancer and alkaline foods do not - these are pseudoscience. The American who concocted this theory to defraud people, Robert O. Young, was ordered on November 2, 2018, in a San Diego court to pay a cancer patient 105 million US dollars; he admitted in court that his "acid-alkaline body" theory was a hoax.
For years the medical community has been debunking Robert O. Young's hoax, and the law gave him his due punishment. Yet even now some high-school chemistry teachers are still spreading this pseudoscience, which I find surprising.
How many people can one such teacher influence? On Bilibili alone, his courses are watched by hundreds of thousands of high-school students; after listening to him, they will become propagators of this fallacy. I had assumed natural-science teachers would not make such elementary errors, but surprisingly some of the very best among them do. This shows that our medical science popularization is far from sufficient. If natural-science teachers are themselves deceived, the general public is even more inevitably so.