I don’t remember how I picked up The Body: A Guide For Occupants, but I am very happy that I did. The book offers a scientific and anatomical look at a human body from top to bottom, from outside to inside. It’s full of details and discoveries that I didn’t know before. We often say that we know our body most, but do we? Of course, we can tell if something is wrong, but many of us, I believe, don’t possess a basic understanding of how our body works. If this is something that you are interested in, pick up this book and give it a try.
There are two things that I really like about this book. The first is that the author managed to tell a compelling story about our body so that even laymen like myself can follow and understand. Every chapter’s content is driven by research and some are more technical than others, but overall, even without background in physiology or anatomy, readers can expect to leave this book knowing more about a human body. I also love some of the historical stories that give spotlight to unsung heroes who contributed massively to science but didn’t get the credit that they fully deserve. For instance, Albert Schatz worked tirelessly to discover streptomycin, one of the great microbiological breakthroughs of the previous century. Nonetheless, he didn’t receive credit as well as financial rewards that a discovery of that magnitude should warrant him. I wouldn’t know about him if I hadn’t read this book and for that, I am grateful to the author.
I took a lot of notes throughout the book and here are some of them:
Composition of our body
“Altogether, according to RSC calculations, fifty-nine elements are needed to construct a human being. Six of these—carbon, oxygen, hydrogen, nitrogen, calcium, and phosphorus—account for 99.1 percent of what makes us, but much of the rest is a bit unexpected. Who would have thought that we would be incomplete without some molybdenum inside us, or vanadium, manganese, tin, and copper? Our requirements for some of these, it must be said, are surpassingly modest and are measured in parts per million or even parts per billion. We need, for instance, just 20 atoms of cobalt and 30 of chromium for every 999,999,999½ atoms of everything else.”
“Thorium costs over $3,000 per gram but constitutes just 0.0000001 percent of you, so you can buy a body’s worth for thirty-three cents. All the tin you require can be yours for six cents, while zirconium and niobium will cost you just three cents apiece. The 0.000000007 percent of you that is samarium isn’t apparently worth charging for at all. It’s logged in the RSC accounts as costing $0.00”
“Cadmium, for instance, is the twenty-third most common element in the body, constituting 0.1 percent of your bulk, but it is seriously toxic. We have it in us not because our body craves it but because it gets into plants from the soil and then into us when we eat the plants. If you are from North America, you probably ingest about eighty micrograms of cadmium a day, and no part of it does you any good at all.”
Microbes and viruses
“Luckily, most microbes have nothing to do with us. Some live benignly inside us and are known as commensals. Only a tiny portion of them make us ill. Of the million or so microbes that have been identified, just 1,415 are known to cause disease in humans—very few, all things considered. On the other hand, that is still a lot of ways to be unwell, and together those 1,415 tiny, mindless entities cause one-third of all the deaths on the planet.”
“More recently, Dana Willner, a biologist at San Diego State University, looked into the number of viruses found in healthy human lungs—somewhere else that viruses were not thought to lurk much. Willner found that the average person harbored 174 species of virus, 90 percent of which had never been seen before. Earth, we now know, is aswarm with viruses to a degree that until recently we barely suspected”
“The common cold is not a single illness but rather a family of symptoms generated by a multiplicity of viruses, of which the most pernicious are the rhinoviruses. These alone come in a hundred varieties. There are, in short, lots of ways to catch a cold, which is why you never develop enough immunity to stop catching them all.”
Penicillin and two unsung heroes
“With Britain preoccupied by World War II and the United States not yet in it, the quest to produce bulk penicillin moved to a U.S. government research facility in Peoria, Illinois. Scientists and other interested parties all over the Allied world were secretly asked to send in soil and mold samples. Hundreds responded, but nothing they sent proved promising. Then, two years after testing had begun, a lab assistant in Peoria named Mary Hunt brought in a cantaloupe from a local grocery store. It had a “pretty golden mold” growing on it, she recalled later. That mold proved to be two hundred times more potent than anything previously tested. The name and location of the store where Mary Hunt shopped are now forgotten, and the historic cantaloupe itself was not preserved: after the mold was scraped off, it was cut into pieces and eaten by the staff. But the mold lived on. Every bit of penicillin made since that day is descended from that single random cantaloupe.”
“In 1945, he shared the Nobel Prize in Physiology or Medicine with Ernst Chain and Howard Florey. Florey and Chain never enjoyed the popular acclaim they deserved, partly because they were much less gregarious than Fleming and partly because his story of accidental discovery made better copy than their story of dogged application. Chain, despite sharing the Nobel Prize, became convinced that Florey had not given him sufficient credit, and their friendship, such as it was, dissolved.”
Pharmaceutical patens include clinical trials. Hence, exclusive patent protection is usually just five years
“Yet as the problem has grown, the pharmaceutical industry has retreated from trying to create new antibiotics. “It’s just too expensive for them,” Kinch says. “In the 1950s, for the equivalent of a billion dollars in today’s money, you could develop about ninety drugs. Today, for the same money, you can develop on average just one-third of a drug. Pharmaceutical patents last only for twenty years, but that includes the period of clinical trials. Manufacturers usually have just five years of exclusive patent protection.” In consequence, all but two of the eighteen largest pharmaceutical companies in the world have given up the search for new antibiotics. People take antibiotics for only a week or two. Much better to focus on drugs like statins or antidepressants that people can take more or less indefinitely. “No sane company will develop the next antibiotic,” Kinch says.”
If teenagers are reckless, it’s likely because of their brains
“The brain takes a long time to form completely. A teenager’s brain is only about 80 percent finished (which may not come as a great surprise to the parents of teenagers). Although most of the growth of the brain occurs in the first two years and is 95 percent completed by the age of ten, the synapses aren’t fully wired until a young person is in his or her mid- to late twenties. That means that the teenage years effectively extend well into adulthood. In the meantime, the person in question will almost certainly have more impulsive, less reflective behavior than his elders and will also be more susceptible to the effects of alcohol. “The teenage brain is not just an adult brain with fewer miles on it,” Frances E. Jensen, a neurology professor, told Harvard Magazine in 2008. It is, rather, a different kind of brain altogether.
“The nucleus accumbens, a region of the forebrain associated with pleasure, grows to its largest size in one’s teenage years. At the same time, the body produces more dopamine, the neurotransmitter that conveys pleasure, than it ever will again. That is why the sensations you feel as a teenager are more intense than at any other time of life. But it also means that seeking pleasure is an occupational hazard for teenagers. The leading cause of deaths among teenagers is accidents—and the leading cause of accidents is simply being with other teenagers. When more than one teenager is in a car, for instance, the risk of an accident multiplies by 400 percent.”
Stigma around Monosodium Glutamate may be exaggerated
“Monosodium Glutamate or MSG has had a hard time of it in the West since 1968 when The New England Journal of Medicine published a letter—not an article or a study, but simply a letter—from a doctor noting that he sometimes felt vaguely unwell after eating in Chinese restaurants and wondered if it was the MSG added to the food that was responsible. The headline on the letter was “Chinese-Restaurant Syndrome,” and from this small beginning it became fixed in many people’s minds that MSG was a kind of toxin. In fact, it isn’t. It appears naturally in lots of foods, like tomatoes, and has never been found to have deleterious effects on anybody when eaten in normal quantities. According to Ole G. Mouritsen and Klavs Styrbaek in their fascinating study, Umami: Unlocking the Secrets of the Fifth Taste, “MSG is the food additive that has been subjected to the most thorough scrutiny of all time,” and no scientist has ever found any reason to condemn it, yet its reputation in the West as a source of headaches and low-grade malaise now appears to be undimmed and permanent.”
“Diabetes comes in two varieties. Indeed, it is really two diseases, with similar complications and management issues but generally different pathologies. In type 1 diabetes, the body stops producing insulin altogether. In type 2 diabetes, insulin is less effective, usually because of a combination of decreased production and because the cells on which it acts don’t respond as they normally would. This is referred to as insulin resistance. Type 1 tends to be inherited; type 2 is usually a consequence of lifestyle. But it’s not quite as simple as that. Although type 2 is unequivocally associated with unhealthy living, it also tends to run in families, suggesting a genetic component. Similarly, although type 1 diabetes is associated with a fault in a person’s HLA (human leukocyte antigen) genes, only some people with the fault get diabetes, indicating that there is some additional, unrecognized trigger. Many researchers suspect a link to levels of exposure to a range of pathogens in early life. Others have suggested an imbalance in the victim’s gut microbes or possibly even a connection to how comfortable and well nourished one was in the womb.”
“NOT ALL GLANDS are tiny, of course. (For the record, a gland is any organ in the body that secretes chemicals.) The liver is a gland and it is, compared with the rest of our glands, gigantic. When fully grown, it weighs about 3.3 pounds, roughly the same as the brain, and fills much of the central abdomen just below the diaphragm. It is disproportionately large in infants, which is why their bellies are so delightfully rounded.”
“It is also the most multifariously busy organ in the body, with functions so vital that if it shuts down, you will be dead within hours. Among its many jobs, it manufactures hormones, proteins, and the digestive juice known as bile. It filters toxins, disposes of obsolescent red blood cells, stores and absorbs vitamins, converts fats and proteins to carbohydrates, and manages glucose—a process which is so vital for the body that its dilution for even a few minutes can cause organ failure and even brain damage”
“Perhaps the most wondrous feature of the liver is its capacity to regenerate. You can remove two-thirds of a liver and it will grow back to its original size in just a few weeks. “It’s not pretty,” the Dutch geneticist Professor Hans Clevers told me. “It looks a bit battered and rough compared with the original liver, but it functions well enough. The process is something of a mystery. We don’t know how a liver knows to grow back to just the right size and then stop growing, but it is lucky for some of us that it does.”
Benefits of exercise and the harm of too much sitting
“Study after study since then has shown that exercise produces extraordinary benefits. Going for regular walks reduces the risk of heart attack or stroke by 31 percent. An analysis of 655,000 people in 2012 found that being active for just eleven minutes a day after the age of forty yielded 1.8 years of added life expectancy. Being active for an hour or more a day improved life expectancy by 4.2 years.”
“And how much exercise should we get? That’s not easy to say. The more or less universal belief that we should all walk ten thousand steps a day—that’s about five miles—is not a bad idea, but it has no special basis in science. Clearly, any ambulation is likely to be beneficial, but the notion that there is a universal magic number of steps that will give us health and longevity is a myth. The ten-thousand-step idea is often attributed to a single study done in Japan in the 1960s, though it appears that also may be a myth. In the same way, the Centers for Disease Control’s recommendations on exercise—namely, 150 minutes per week of moderate activity—are based not on the optimal amount needed for health, because no one can say what that is, but on what the CDC’s advisers think people will perceive as realistic goals.”
“Amazingly, and alarmingly, it doesn’t seem to matter how much you exercise the rest of the time. If you spend an evening on the seductive padding of your gluteus maximus, you may nullify any benefits you gained during an active day. As James Hamblin put it in The Atlantic, “You can’t undo sitting.” In fact, people with sedentary occupations and sedentary lifestyles—which is to say, most of us—can easily sit for fourteen or fifteen hours a day, and thus be completely and unhealthily immobile for all but a tiny part of their existence.”
Sugar – Fruits may not be as healthy as we think
“By one estimate, about half the sugar we consume is lurking in foods where we are not even aware of it—in breads, salad dressings, spaghetti sauces, ketchup, and other processed foods that don’t normally strike us as sugary. Altogether about 80 percent of the processed foods we eat contain added sugars. Heinz ketchup is almost one-quarter sugar. It has more sugar per unit of volume than Coca-Cola.”
“Many of our fruits and vegetables are nutritionally less good for us than they were even in the fairly recent past. Donald Davis, a biochemist at the University of Texas, in 2011 compared the nutritive values of various foods in 1950 with those of our own era and found substantial drops in almost every type. Modern fruits, for instance, are almost 50 percent poorer in iron than they were in the early 1950s, and about 12 percent down in calcium and 15 percent in vitamin A. ”
Excerpt From: Bill Bryson. “The Body: A Guide for Occupants.” Apple Books.