The reason why natural selection «doesn’t care as much» about women’s health

The body of modern women seems to be the epicenter of an intense conflict of interests.

On the one hand, there would be their reproductive capacity and, on the other, their health.

“Many women put a lot of effort into following what they’ve been told is a healthy lifestyle. They don’t smoke, cut fatty foods out of their diets, cut down on sweets, take the stairs instead of the elevators, and walk to work.»

“When they get breast cancer, a heart problem or osteoporosis, they often blame themselves and ask themselves: ‘What did I do wrong?‘” says the book The Fragile Wisdom, by biological anthropologist Grazyna Jasienska.

But the truth is that blaming yourself makes no sense.

Although, the author acknowledges, there are practices that are totally harmful and should be avoided, we should not blame ourselves for getting sick.

And it is that, he tells BBC Mundo, there are many factors that intervene in this process. For example, «it could be genetic, it could be due to some kind of interaction, an accident in our physiology.»

Jasienska is a professor at the Department of Epidemiology and Population Studies at the Jagiellonian University in Poland and is trying to understand why preventing diseases in women can be so difficult.

In its book description, Harvard University Press sums up the essence of what it calls the conflict of interest in the female body:

«Women’s physiology has evolved to facilitate reproduction, not to reduce disease risk.»

For this reason, the researcher goes back several thousand years in search of answers.

a priority

«The past allows us to understand what is happening to women today in terms of health and physiology,» she says in our interview.

Grazyna JasienskaOne of Grazyna Jasienska’s research fields is human evolutionary ecology. (Photo: COURTESY: GRAZYNA JASIENSKA)

Our evolutionary legacy carries weight when it comes to cancer and reproduction.

“In evolutionary terms, passing genes to the next generation is always more important to be healthy”, holds.

«Of course you need to be healthy to pass them, it is an important part of that process, you have to survive, find a partner to reproduce», but «whatever it is» that happens to the organism to support that transfer, it will be “more important than anything”.

For example, she explains, the chances of breast cancer in women increase in relation to “lifetime exposure to estrogens”, hormones that are extremely important for pregnancy.

«The higher that lifetime exposure, the higher the risk of breast cancer.»

Drawing of a woman with breast cancer(Photo: GETTY IMAGES)

“One might ask: why is natural selection, the main mechanism for evolutionary change, does not make us different to stop producing such high levels of estrogen, if estrogen is so bad for your health when it comes to breast cancer?”

The answer is direct: because estrogens help reproduction.

«It doesn’t matter what kind of harmful consequences high estrogen has for life as long as it supports gene transmission to the next generation.»

Natural selection «doesn’t care as much» about women’s health as their ability to reproduce.

“Estrogens, a group of female sex hormones, are known human carcinogens. Although these hormones have essential physiological functions in both women and men, they have also been associated with an increased risk of certain cancers.»

US National Cancer Institute

more menstrual cycles

The professor has investigated the dramatic change in the number of menstrual cycles.

female reproductive system(Photo: GETTY IMAGES)

“It is estimated that in what we would call the Stone Age, women were only about 100 cycles throughout their lives.»

There is no certainty of the reason. It is believed that it is because they matured later, although it may also have influenced that they entered menopause earlier.

«The first period was much later than women experience it now, we don’t know how much later, but maybe around 16 years old.»

That variation has added a few years of menstrual cycles to the lives of women who developed at 12, 13 years old.

Also, our ancestors had more children and pregnancy and breastfeeding have an effect on periods.

This is how «modern women have about 450 cycles during life instead of 100″.

woman with a calendar(Photo: GETTY IMAGES)

«That’s a huge difference when you think about exposure to estrogen» because these hormones, which are secreted by the ovary, play a regulatory role in the menstrual cycle.

According to the professor, the way these cycles develop has also changed. For example, they have higher levels of hormone production than in the past.

«When it comes to estrogen exposure and modern life, we find that we have more cycles and of a different quality» and that translates into «greater exposure to hormones.»

«Breast cancer cells have receptors (proteins) that attach to estrogen and progesterone, which helps them grow.»

American Cancer Society

The price

“Whatever you do in life, there will be some costs associated with it. If you physiologically focus on reproduction, there will be a cost,” says the professor.

For example, the same level of energy that you dedicate to reproduction, you will not assign it to other functions of your own organism and that can cause other aspects of your health to suffer.

growth of a woman

“Because you invested energy in reproduction, the immune system is going to suffer. The risk of contracting infections is going to increase and, because of that, other aspects in which the immune system is involved are going to be affected”.

“In a way, you accumulate damage during your reproductive years by the fact that you are in that role.”

«And of course natural selection doesn’t care much about us in the post-reproductive stage.»

“Reproduction in human females is expensive, in terms of energy, nutrients and metabolic adjustments. Therefore, women who experienced high reproductive stress as a result of multiple reproductive events would be expected to age faster. However, the evidence for the long-term negative effects of reproduction is inconclusive.»

“Many studies have documented that women with intense reproduction have an increased risk of age-related diseases“.

«In humans, as in any other species, natural selection has favored traits that are beneficial for successful reproduction, although they may not be beneficial for health, especially in old age.»

Jasienska in Costs of reproduction and aging in the human female.

The grandmother hypothesis

However, the expert raises the call grandmother Hypothesis, which states that when women reach the stage where they cannot have more offspring, although «they cannot pass genes directly to the next generations», in a certain way they do by helping their children and grandchildren pass them on.

Grandmother playing with her grandson(Photo: GETTY IMAGES)

“In that sense, one could say that natural selection does not immediately kill us when we become post-productive because there is still an evolutionary sense“.

«In many species, females live as long as they can reproduce and manage to do so until the end of their lives.»

“We can live much longer (after that stage) and there is a lot of discussion about that from the perspective of biology. evolutionary”.

“Why keep us alive for so long if we are not able to pass on genes, which is the biological evolutionary purpose of life?”

The grandmother hypothesis is one explanation, he says. «Perhaps women still have an evolutionary role.»

The diet of the ancestors?

The teacher believes that although cancer is also related to the modern lifestyle, there are other factors that can intervene in this disease.

The same goes for other ailments.

Woman talking to her doctor

The Fragile Wisdom poses a reality: we hear daily how different diseases can be prevented by living a healthy life, but when we get sick, the feeling that we have somehow failed to follow what is recommended can become overwhelming.

“What is a proper diet? Some people propose what they call the Stone Age diet, ”he tells BBC Mundo.

«The Stone Age diet didn’t exist because there was a huge variety of diets depending on whether you were in a cold climate or in the desert or on the coast.»

drawing of two women(Photo: GETTY IMAGES)

“There is the idea that if we eat the way our ancestors did, we will be healthy, slim and beautiful, but no, it doesn’t work that way because they ate many types of food and humans, in general, They evolved to eat many things.”

“I think that was something that happened in evolution: we don’t need a very particular diet to survive. We have evolved to eat very different things and be well.

And that’s a wonderful thing from our past.»

Don’t look for perfection

“We are only human, we cannot be perfect. Also, we don’t know how to be because some of the health recommendations often change.»

woman exercising(Photo: GETTY IMAGES)

And an example of them are precisely diets.

“People tell you one thing: Eggs are really bad, but then a different study says they’re good. There is an article that says that coffee is harmful and then another that assures that it is perfect and that with three or four daily cups your health will be better”.

“Many of the health messages they are very confusing“, although others are absolutely clear and proven: “if you smoke you ruin your life and then you could blame yourself”.

Trying to take care of our diet and exercising is important.

But the truth is that health is very complicated: «there are many interactions, you don’t have to try to be perfect all the time.»

«We must take care of ourselves and not only for ourselves, but for our families and friends, we do not want to be a burden to anyone.»

«It would be nice to be active and healthy in old age, but if we’re not, it doesn’t mean it’s our fault.»

«We never know if it could be genetic, it could be due to some kind of interaction, an accident in our physiology.»

«Nothing makes sense…»

Another aspect is physical activity, something in which our ancestors surpassed us.

women of three generations(Photo: GETTY IMAGES)

“Of course physical activity is very good for health. But how much should we do? We do not know yet. There are many organizations that will tell you three times a week, others that many minutes, some will recommend something else.

But it depends on the requirements and health status of each person.

In some of her academic articles, Jasienska evokes the famous phrase of the Ukrainian geneticist Theodosius Dobzhansky: “Nothing makes sense in biology if it is not in the light of evolution“.

In fact, in the text Public health needs evolutionary thinking, the researcher paraphrases it: “Nothing in demography and public health makes sense if it is not in the light of evolution”.

And it is that he believes that «we cannot really understand the functioning of any organism until we apply the evolutionary approach».

As Laura G. Goetz notes in an article in the Yale Journal of Biology and Medicine: «As fascinating as it is educational, The Fragile Wisdom raises as many questions as it answers, in the best way possible.»

It may interest you:

* “I want to get off this rollercoaster of symptoms and emotions”: The physical and emotional complications that women with thyroid problems live with* The eating habits that prolong your life by at least 10 years* What carbohydrates can make you live to be one hundred years

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