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 sick with breast cancer, a heart problem or osteoporosisthey often blame themselves and ask themselves: ‘What did I do wrong?’«, points out 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 World, There are many factors involved in that process. For example, “it might be genetic, it might 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 the description of his book, Harvard University Press summarizes the essence of what he 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.
Our evolutionary legacy carries weight when it comes to cancer and reproduction.
“In evolutionary terms, pass genes to the next generation is always more important to be healthy,” he says.
“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, he 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.”
“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” regarding 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.”
U.S. National Cancer Institute.
more menstrual cycles
The professor has investigated the dramatic change in the number of menstrual cycles.
“It is estimated that in what we would call the Stone Age, women were only regarding 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 regarding 450 cycles during life instead of 100″.
“That’s a huge difference when you think regarding 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.
“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 regarding 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 so-called grandmother hypothesis, which states that when women reach the stage in which they cannot have more offspring, although “they cannot pass genes directly to the following generations”, in a certain way they they do by helping their children and grandchildren pass them on.
“In that sense, one might say that natural selection doesn’t immediately kill us when we become post-productive because there’s still an evolutionary sense.”
“In many species, females live as long as they can reproduce and manage to do so without natural selection until the end of their lives.”
“We can live much longer (following that stage) and there’s a lot of discussion regarding that from an evolutionary biology perspective.”
“Why keep us alive for so long if we are not able to pass on genes, which is the evolutionary biological purpose of life and natural selection?”
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.
The Fragile Wisdom raises a reality: we hear daily how different diseases can be prevented by leading a healthy life, but when we get sick, the feeling that somehow we failed in the attempt 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.”
“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.”
Do not seek perfection in natural selection
We are only human, we cannot be perfect. Also, we don’t know how to be because some of the health recommendations frequently change.”
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 ensures 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 there you might blame yourself».
Trying to take care of our diet and exercising is important.
But the truth is that it is very complicated in terms of health: “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 might be genetic, it might 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.
“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 her: «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.”
