Stress hormones coursing through your body. Fear. Pain. impotence. Max Nieuwdorp (45), an internist-endocrinologist specializing in hormones, also experienced first-hand how powerful these substances are.

    Eleven years ago, he woke up in an ICU bed with a sharp gash across his stomach and a cut on his neck, both with stitches. Nearby was his two-year-old son, who had life-threatening childhood liver cancer. He had donated part of his own liver and a few blood vessels from his neck to him. His wife sat at his bedside, having just given birth to their third child.

    “I now understand better what an impact stress can have on your entire body, on your immune system, your mood, your appetite, your gut. I also saw how this affected my daughter, a cry baby, who was exposed to a stress hormone for six months in the womb. She had an indomitable appetite for a long time.” Nieuwdorp thought he could go back to work after two weeks, but he was ready after three months.

    Then the seed was planted for his book We are our hormones, which appeared on September 1. In it he describes in an accessible manner how hormones run our bodies day after day, from cradle to grave. He intersperses the latest scientific insights with stories about patients, but also about hormones gone wrong in world leaders and biblical figures. From 2016, he found the peace to write it, in stolen hours in the morning and in the evening, when patients, researchers and his young family did not demand attention. His children are doing well, his son is now a footballing teenager.

    Nieuwdorp wrote the book to give patients insight, he says in his office at his vascular medicine department at the Amsterdam UMC. “There is a lot of misunderstanding about hormones, there is a lot of pseudoscience going around. I wanted to show what happens in illness and in a healthy body. How closely hormones work together. And what the influence of the environment is on this, of stress, food, harmful substances.”

    Wink to Dick Swaab

    The title is a nod to the bestseller We are our brain, by neurobiologist Dick Swaab. The brain is decisive, says Nieuwdorp. But hormones control every function in the body minute by minute. Also that of the brain. Blood pressure, growth, aging, sugar levels, mood, appetite, sleep, sex drive and everything that follows, the response to danger: everything is regulated by hormones. They are made by glands throughout the body, and released into the bloodstream to exert their influence elsewhere. For example, hormones such as adrenaline, insulin, serotonin and testosterone control the body. These are delicate balances, with major consequences if they become unbalanced.

    And that often happens. 1.2 million Dutch people alone have diabetes, half a million have an underactive thyroid, 1.9 million adults are obese, with all kinds of hormones out of balance. And 1.2 million women are in the menopause, just as many men are struggling with declining testosterone.

    The biggest misunderstanding among his patients? They expect that their disease can be cured with a hormone pill. But it’s not like that, he says. “If you make too little thyroid hormone, you often also have menstrual problems, intestinal problems or psychological complaints. Sex hormones, thyroid hormone, the stress hormone cortisol: all those hormones influence each other, everything is interrelated.”

    The entanglement makes treatment difficult. Nieuwdorp is regularly left empty-handed. “We can only treat hormone disorders very roughly: we give back thyroid hormone, or insulin, for example. But in the body, hormones are not released evenly, that goes with peaks and troughs. There are day-night rhythms, there is influence of body processes, of seasons. That variability determines our well-being.” This means that doctors sometimes see a good blood value, but the patient does not feel completely healthy. “It often doesn’t get heard. People with a hormone disease give their lives an average of 7, but of course they also prefer an 8.”

    A dream for now

    “My dream is that we can better imitate natural production in hormone diseases,” says Nieuwdorp. “In the same way as with the artificial pancreas in type 1 diabetes. Then a patient is given a glucose meter and a pump that releases hormones throughout the day if the value is too high or too low.” For the time being, that remains a dream for hormone diseases other than diabetes.

    Also read: Constant finger sticks and self-administering insulin are a thing of the past thanks to this pump

    Also difficult: every body reacts differently to hormone changes. For example, Nieuwdorp had a patient with an overactive thyroid. “Most patients don’t have much of this, other than a rapid heartbeat and trembling hands. But this woman became sexually disinhibited. She crawled into bed with every male patient. Once a surgeon had removed the thyroid, it was over.”

    It intrigues Nieuwdorp. Why does one patient function as before after treatment and the other remains incapacitated for work? “There has to be a different interaction in those different bodies, and maybe also with the environment.” In the consulting room he always asks about the family situation, work, how someone sleeps and eats, whether there is stress. “A patient is not just a body with disrupted hormones, he is part of a system.”

    The environment is also part of that system. But the influence of harmful substances in it is not addressed in medical training, he says. “Since the 1970s, more and more ultra-processed and high-calorie foods have entered our diet, leading to obesity. And many more hormone-disrupting substances such as PFAS, plasticizers in plastics and pesticides. And certain autoimmune diseases, such as thyroid disease, type 1 diabetes, and inflammatory bowel disease, have also increased since then, while humans have remained genetically the same.”

    A stacking effect

    Nieuwdorp suspects that hormone disruptors play a role in this increase. It is an epidemiological link – whether they are really the cause of disease is difficult to prove. “Because it’s an accumulating effect, you have to be exposed to it for a long time. And that also applies the other way around: by stopping drinking from a plastic bottle, as some websites recommend, you will not suddenly feel better. But we should not wait until we establish a causal relationship.”

    Because treatments often do not completely solve the complaints, it is not surprising that patients look for alternative treatments. Nieuwdorp is not in favor of this. “But I also don’t want to shoot it off in advance. For example, there seems to be a beneficial effect of yoga on blood sugar in people with diabetes.” He can imagine that it works by reducing stress. “Chronic stress has an effect on blood sugar levels.” You cannot replace a pill with food, or with yoga, he thinks. “But we do have to look at how eating and living habits can enhance the effect of medicines. Fortunately, the new generation of doctors is paying more attention to this.”

    I have seen patients who took black cohosh or St John’s wort and developed massive liver dysfunction

    He is not pleased with alternative practitioners who prescribe red clover with plant estrogen, or stress or sex hormones. “The interplay is complicated, and hormones are powerful, you shouldn’t mess with that too much. Certainly not if you do not know whether it is really the cause of your complaints, and if you do know that there is always a downside.”

    “If you give a stress hormone in the case of, for example, a disturbed adrenal function, it will take things even further off the rails.” And you should also be cautious with testosterone in men or estrogen in menopausal women. With prolonged use, they increase the risk of cancer and cardiovascular disease. “Over the past twenty years, doctors have not given any hormones at all to women with menopausal complaints, which is also too brutal. Perhaps we can give it pulse-wise in case of serious complaints, or for a few months. But sometimes we have to accept the biological processes.”

    He always asks patients if they use alternative preparations. “I have seen patients who took black cohosh or St. John’s wort and developed massive liver dysfunction from taking a contraceptive pill.”

    The hope is that we can make medicines work better

    And then there’s something else that affects the delicate balance of our hormones: that of the microbiome, the bacteria in our gut. In 2006, Nieuwdorp was the first doctor in the Netherlands to perform a poo transplant on a woman with severe diarrhea caused by intestinal bacteria. Clostridium difficile. That is now a common treatment when antibiotics don’t work.

    Nieuwdorp thinks that gut bacteria play an important role in thyroid disease, type 1 diabetes, and perhaps obesity. “The hope is that we can make drugs work better, or delay their use by changing the gut flora.” That still requires a lot of research. Desperate patients don’t want to wait for that. “Some patients give themselves poo transplants with the help of YouTube videos. They take poop from a roommate. They drink that or they insert it rectally with an enema.” Not a good idea, he emphasizes. “People have been operated on for an intestinal infection because of this.”

    You can’t lean back. Doctors can help you, but it’s your disease

    In his book, Nieuwdorp also gives tips for what people can do themselves. “Sleep enough, exercise, eat healthy, reduce stress. A lot of things are exacerbated or amplified by lifestyle. You have to do something about that yourself, within your means. You can’t lean back. Doctors can help you, but it’s your disease.”

    Nieuwdorp himself relaxed during the stressful hospital period by reading a lot – this is reflected in his book. Running marathons is no longer possible since the operation, his scars are too much. But he likes to take long walks. And he cycles to work in the AMC three times a week, from the center of Amsterdam. “My working days are often overcrowded, I notice that I come home more relaxed because of this. That makes me keep doing it.”

    Max Nieuwdorp. We are our hormones. The Busy Bee, 304 pp.