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Source: Dad talks about science
Author: Wu Xingchuan
Many older people have this memory: your mother brought you a bowl of bitter decoction, and you refused to drink it because it was too bitter, at this time, your mother would say to you bitterly:
"Drink it, kid, the medicine is bitter. ”
Under the resistance and persuasion again and again, you will gradually be able to swallow those unpalatable decoctions, and even over time, you will develop an attachment to that bitterness.
Medicine is bitter – you say this to yourself, and then you tell your child this.
Of course, the hearts of parents are good, but the saying "good medicine is good for the sick" may not be so correct from a scientific point of view.
Because what is bitter is not necessarily good medicine, it can also be poison.
One fact we need to understand is this: in nature, the bitter taste of certain plants often means – they are poisonous.
"Poison" and "thorn" are self-protection mechanisms that plants have evolved to survive and reproduce in the cruel competition of nature.
In the natural world of "survival of the fittest", any trait that is not adapted to the environment at that time may make a certain organism face extinction, and the organism needs to rely on evolution to make itself more suitable for the environment at that time.
For example, some of the ancestors of cheetahs acquired the "fast running gene" through mutation, which greatly enhanced their survivability, while those subspecies that failed to evolve the "fast running gene" were either killed by more powerful predators, or gradually eliminated by nature because they did not run fast enough.
Other animals with fangs, claws, and horns are also the victors chosen by nature in this fierce competition.
However, compared to those birds and beasts with various "special functions", what kind of mechanism should relatively weak plants evolve to ensure their survival?
The answer is imminent: sharp thorns, and deadly poison.
These two seemingly simple traits can allow some relatively weak plants to survive in front of powerful animals.
Although there are always some animals that are not afraid of pain, sharp thorns cannot stop them, and what can stop them at this time is deadly poison.
The problem is that, unlike intuitive stings, poison attacks are often not so timely, and if you don't stop hungry animals before they eat them all, the result can be a lose-lose situation – one is eaten and the other is poisoned.
At this time, another self-protection mechanism that some animals have acquired in their evolution has shown its power.
In the long process of evolution, some animals, including humans, have evolved a gene that can distinguish whether food is poisonous or not, TAS2R38.
TAS2R38 gene, on human chromosome 7
In the case of human ancestors, when eating a poisonous plant, the brains of human ancestors with TAS2R38 genes received a signal that the taste of the plant was bitter.
While not all bitter plants are poisonous, in general, poisonous plants tend to be bitter, such as oleander, alocasia, castor, mandala, and the famous, smelly Aristolochia genus.
Aristoloch: The aristolochic acid it contains is nephrotoxic and is a carcinogen
TAS2R38 genes are very powerful in identifying toxicity not only by sensing bitterness, but also by sensing the bitterness of other foods, even non-foods, such as moldy nuts (containing aflatoxin), sprouted potatoes, and some heavy metals that should not be consumed.
TAS2R38 genes exist, it is a kind of protection for our ancestors from poisoning or even poisoning when they feed on plants.
However, not all humans with TAS2R38 genes can taste bitterness, and TAS2R38 genes are divided into two coding types, namely the dominant gene G and the recessive gene C, where the receptor encoded by the G gene can make people taste the bitter taste of food, while the receptor encoded by the C gene cannot taste the bitter substance.
According to the combinatorial arrangement, humans with TAS2R38 genes are divided into four types: GG, GC, CG, and CC.
Among them, people with GG genes are the most sensitive to bitterness, and they are even very resistant to coffee, tea, and some vegetables with less obvious bitterness, people with CC genes are the least sensitive to bitterness, and their advantages are that they can endure bitterness, and their disadvantages are also able to endure bitterness, while GC and CG are the same thing, they are the largest part of the population with "normal taste".
After the first difficult years, humans who have established a civilized society can use language and writing to warn their peers of what is poisonous, and no longer need to discern by taste alone.
Later, through the examination of food and drugs by modern science, humans have been able to understand more clearly what is toxic and what is safe.
Objectively speaking, although bitter plants may be poisons, the bitter metabolites secreted by some plants are indeed medicinous, but this requires scientific research to understand which ingredients can treat which diseases, and then extract their active ingredients to make modern medicines, rather than relying on superficial ancestral experience and concoction based on analogy for compatibility and concoction.
Of course, most chemical drugs also have a bitter taste, so they often have coatings or capsules, which are the same as botanical ingredients on this level - many chemicals are toxic. Therefore, bitter mouth is generally a toxic suggestion, and whether it can be used as a drug for the treatment of a certain disease needs to be scientifically evaluated.
Therefore, we can see that the instructions of those chemical drugs always list the toxic and side effects as much as possible, so as to help patients weigh the pros and cons and make a choice with as complete information as possible.
Instead of relying on a simple sentence of "it is a medicine with three poisons", it is easy to seize the patient's right to obtain information and the right to choose.
However, there are always some people who ignore the warnings of science, ignore the toxins that may exist in natural plants, and insist on going their own way on the road to death.
For such people, we can only use four words to describe - self-inflicted.