An invisible blow to masculinity: insulin resistance as an enemy of male fertility

I'll surprise you if you ask me the reason - because one of the main culprits of this tragedy of our time is the recently popular, though unfortunately rarely considered in the process of trying to get pregnant, male insulin resistance.

As a physician, endocrinologist and witness to hundreds of men's stories from the office, I can say with confidence today: insulin resistance is one of the most underestimated killers of male fertility.

When testosterone falls silent and insulin screams

Insulin is not only a metabolic hormone - it is also a hormone of endocrine balance. Its chronic elevation, caused by reduced cellular sensitivity, wreaks havoc on our endocrine system, and more specifically, most affects the so-called hypothalamic-pituitary-gonadal axis. High insulin levels reduce SHBG (sex hormone-binding globulin) levels, leading to an increase in free estrogen and a relative shortage of testosterone. The consequences? Decreased libido, fatigue, visceral fat gain, gynecomastia, and most importantly: deterioration of semen parameters.

"But I'm thin" - or the myth of the lean IO man

Many of us live under the belief that insulin resistance is the domain of obese people. Meanwhile, science is clear: even normal-weight people can develop so-called peripheral insulin resistance, especially in the context of high stress, sleep disorders, chronic inflammation and poor diet. What's more - in men with a genetic risk of metabolic syndrome, insulin resistance often develops unseen, leading to semen quality problems and sometimes even azoospermia. Azoospermia is a condition in which no sperm is found in a man's semen. This is one of the main causes of male infertility,because, as you can easily guess, without sperm, natural conception is not possible.

Biochemical sabotage - or the ways in which insulin harms the testes

Insulin resistance, as in the case of women as I wrote about earlier, negatively affects male fertility on several levels, and these are in a nutshell:

Disorders of the HPT (hypothalamus-pituitary-testis) axis - hyperinsulinemia, that is, too high a concentration of insulin in the blood suppresses the pulsatile secretion of GnRH, reducing the production of gonadotropins by the pituitary gland,thus both LH and FSH.

Steroidogenesis disorders - high insulin levels and inflammation in the testes interfere with the production of testosterone and the conversion of cholesterol, from which the most important sex hormones for most men are formed.

Disorders of spermatogenesis - chronic hyperglycemia, or too-high blood glucose levels, and oxidative stress damage Sertoli and Leydig cells in the testes, key to the formation of sperm cells that are mature and capable of fertilizing an egg.

Decreased semen quality - an increase in sperm DNA fragmentation, taking place in men with insulin resistance, often coexists with reduced motility and worse sperm morphology. This, as I'm sure you've guessed, can very significantly impair male fertility.

Increases in leptin and estradiol - which occur in men with inuslino resistance, and which have anti-androgenic effects - create a hormonal landscape that promotes infertility....

Statistics leave no illusions

As early as 2012, a study of men presenting to infertility clinics found that as many as 45-55% had features of metabolic syndrome, and nearly 30% had overt or latent insulin resistance. A 2021 meta-analysis confirmed that OI is correlated with significant deterioration in sperm count, motility and morphology, as well as reduced testosterone levels and increased prolactin levels.

The story (of Peter) of which there are many these days

Peter, when he came to my office, was 34 years old. Athletic, seemingly healthy. By today's standards - we could put him as a role model for many men between the ages of 30 and 40. In addition, he reported no major ailments. There was only one "but." He and his wife had been trying unsuccessfully for almost three years to have a child. His wife had been under the excellent care of one very good and well-known gynecologist for infertility treatment. What rarely happens, she had all the results according to the one taking care of her - exemplary. Peter's semen tests, on the other hand, were - you guessed it - abnormal. On top of that, testosterone at the lower end of normal, despite a well-slept night in his opinion. Fasting blood glucose 93 mg/dl - according to the patient, which he reportedly repeated word for word after the doctor consulting him earlier: "perfect"! Only the insulin curve revealed full-fledged insulin resistance: 1h post-load insulin: 104 µIU/ml, 2h - 67 µIU/ml. So the values were too high! Fortunately, Peter took the problem quite seriously. In a joint effort, with the active involvement of the patient's partner, we implemented a comprehensive lifestyle modification aimed at improving tissue sensitivity to the patient's own insulin. In parallel, for metabolic reasons, we included classic, proven metformin in the therapy, as well as individually selected - according to body weight and height - supplementation with N-acetylcysteine (NAC), zinc, coenzyme Q10 and L-carnitine. The result? After five months, real joy came into their lives - his wife was pregnant.

Peter, like many other men, previously had no clue that his metabolism was sabotaging his manhood.

You will probably ask, why then are doctors not diagnosing it? The fault lies somewhat with the system-and the still not very precise teaching of this branch of diabetology, because most doctors still equate insulin resistance with diabetes. Until a few years ago, with a candle in your hand you could find a doctor who could correctly interpret the results of a glucose-insulin test-so the same 75 g glucose load curve with simultaneous determination of both fasting glucose and insulin concentrations at 1 h and at 2 h of the test. The problem is also that insulin standards are imprecise and vary from lab to lab. On top of that, our "men's problems" are often downplayed, and the patient is given a suggestion instead of ordering actually needed tests: "Please stress less." But masculinity is not just testosterone. It's also mitochondria in the sperm, DNA quality, cellular energy and microcirculation. And these are closely dependent on insulin management. And here your task is to find an endocrinologist and/or diabetologist familiar with insulin resistance. Fortunately, with each passing year, the awareness of doctors, including specialists in internal medicine, as well as family doctors, is growing, which increases the chance of happily conceiving the desired child. Sometimes such an effect is the resultant of the actions of doctors of several specialties and, most importantly, the man, on whom in fact the most depends in this subject. We - doctors can order the appropriate treatment, refer the patient to an experienced nutritionist or dietician, select an experienced personal trainer who will facilitate the patient's natural reduction of often excessive body weight. In turn, in many situations, the proverbial "cherry to the cake" , or "the desired completion" is precisely selected, properly targeted by experienced specialists, who often have many years of experience in this subject targeted for each specific man - treatment.

For when lifestyle modification alone is not enough, it is following our doctor's recommendations that can actually make us succeed in achieving a healthy desired and long-awaited pregnancy. We should never forget, however, that a healthy pregnancy is not just the effect of drugs or supplements on our patients' bodies, but is often the fruit of a joint effort - the doctor, the nutritionist, the personal trainer, sometimes the psychologist, but above all the patient and his partner. It is in this cooperation, this trust and patience that the real power of modern medicine lies. Because if anyone nowadays denies the correlation of insulin resistance with lifestyle - it means that they do not listen to their own patients, let alone to the voice of science. Fortunately, it seems that the number of people in the medical profession who deny the influence of diet and physical activity on the development and course of many diseases is happily shrinking every year, so that treatment combined with appropriate lifestyle modification gives the best results. And that, after all, is exactly what we want.