The medical field is deeply intertwined with our daily lives, and requires ample studies and tests to ensure the validity of its claims. Many of the guidelines and norms we adhere to in our day-to-day lives are the results of multiple rounds of testing to gauge validity and broader application.
However, the subjects of these studies are often disproportionately men; and often white, able-bodied, cisgender men at that. There are a number of cellular and biological differences between the two sexes that can impact how our bodies interact with different treatments, diets, and illnesses. This is summarized well by Harvard Medical School epidemiologist Tamarra James-Todd: “It’s taboo in some circles to suggest that we’re genetically different from each other, and yet we are. Sex is a biological construct. There are sex differences between men and women, and how those differences manifest and what happens, from a genetic level to how the body operates, is different.”
One of the most distinctive differences between the two sexes is hormonal and cellular makeup. While men and women possess the same hormones, their concentration and distributions vary significantly. For example, women’s hormonal cycle follows a lunar cycle, undergoing significant ebbs and flows over the course of a 28-day period.
During a woman’s single cycle, three hormones (estrogen, progesterone, and testosterone) rise and fall in a specific pattern. In the first two weeks, estrogen levels rise, boosting mood and energy. In the second week, testosterone levels rise as well; this combination of high hormone levels contributes to a good mood and high sex drive. During the third week, progesterone levels rise while estrogen drops, correlating to a sluggish mood, where women can feel emotionally low. In the fourth week, levels of estrogen drop, leading to irritability, moodiness, and body aches. This cycle is governed by the pituitary gland’s interaction with the brain and ovaries.
Comparatively, men’s hormones follow a 24-hour cycle where testosterone peaks in the morning and falls throughout the day. This means that males are likely to be more emotive at this time, as this corresponds with their sex drive.
These differences mean that the two sexes can have drastically different interactions with identical diets, exercise regimens, medical treatments, and illnesses. Brigham and Women’s Hospital in Boston, Massachusetts summarizes this well: “The science that informs medicine - including the prevention, diagnosis, and treatment of disease - routinely fails to consider the crucial impact of sex and gender. This happens in the earliest stages of research, when females are excluded from animal and human studies of the sex of the animals isn’t stated in the published results. Once clinical trials begin, researchers frequently do not enroll adequate numbers of women or, when they do, fail to analyze or report data separately by sex. This hampers our ability to identify important differences that could benefit the health of all.”
Two prominent examples of this are the buzzy ketogenic diet, is characterized by low dietary carbohydrate intake, or intermittent fasting, involving the restriction of one’s daily “eating window” in an effort to switch the body’s energy conversion from sugars to stored body fat.
These are often pushed through advertising on to men and women alike attempting to lose weight or improve metabolic function. However, there is new evidence to suggest that women do not experience identical benefits as men, because “we metabolize fat differently and have a different response to fasting,” UC Riverside biology professor, Frances Sladek, said.
However, due to hormonal fluctuations throughout the 28-day cycle, women have different dietary, physical, and chemical needs. Thus, eating a rigid, low-carb diet identically throughout the month can disrupt hormonal function. The diet is tailored towards men, who operate on that 24-hour window.
There are also a number of illnesses that are influenced by this phenomenon.
Cardiovascular disease is a leading killer of US women. However, it affects women and men differently at each stage, including the symptoms, risk factors, and outcomes from the disease. However, merely a third of cardiovascular disease research is conduced on women, and only 31% of of those woman-inclusive trials report their trial results by sex.
Another example of this phenomenon is with Alzheimer’s disease: 2/3 of the 5.1 million people suffering from the disease are women, and women’s risk of developing the disease based on statistics is twice that of men. The medical field is starting to delve deeper into the reasoning for why this is the case, and is finding that women’s hormonal changes during menopause and differences in sex gene expression could be involved.
Lung cancer are also kills more women each year than breast, ovarian, and uterine cancers combined. After decades of this being the case, there is some evidence being published that sex hormones (specifically, estrogen) could influence the development of the disease. There are more women participating in these trials today, but they are still disproportionately represented compared with men. This is particularly true with women from underrepresented racial groups.
While there is increasing work being done to make medical testing more equitable, results should still be examined through a critical lens. Did the tests publish their subjects’ sexes? If so, was it an equitable distribution? Were the results promoted to both men and women? Unfortunately, women need to continue to be their own advocates in the medical field for the time being.
*This article discusses men and women for the purpose of distinguishing two distinct sexes. TWN acknowledges that gender, however, is a spectrum.