Women Have More Guts Than Men, Literally

Women may be on average around 5 inches shorter than men, but women have around 30cm (11.8 inches) more of the winding muscular tube extending from the stomach to the colon, and this is believed to help women to absorb nutrients better if needed while pregnant and during breastfeeding. 

“The small intestine is all about absorption, absorption, absorption. It’s where you get the vast majority of your nutrients,” says Amanda Hale, co-first author of the study and a Ph.D. candidate at North Carolina State University.

There are not many studies into the possible anatomical variations between people’s organs, thus the researcher measured the digestive tracts of 45 adult cadavers that had been donated to Duke University. 24 of the cadavers were male and 21 were female. On average, the small intestines of the male cadavers were just over 13 feet long, while the female counterparts were around 30 cm longer. 

“There was research more than a century ago that found variability in the relative lengths of human intestines, but this area has largely been ignored since then,” says Hale, co-first author of the study and a Ph.D. candidate at North Carolina State University. “When we began exploring this issue, we were astonished at the extent of the variability we found.”

“If you’re talking to four different people, odds are good that all of them have different guts, in terms of the relative sizes of the organs that make up that system,” says Erin McKenney, corresponding author of the study and an assistant professor of applied ecology at NC State. “For example, the cecum is an organ that’s found at the nexus of the large and small intestine. One person may have a cecum that is only a few centimeters long, while another may have a cecum the size of a coin purse. And we found similar variability for many digestive organs.”

“Because having a longer small intestine helps you extract nutrients from your diet, this finding supports the canalization hypothesis, which posits that women are better able to survive during periods of stress,” says Hale.

Unfortunately, this difference does not explain why some gastrointestinal conditions are more common in one sex/gender than the other. Co-author Dr. Erin McKenney suggests that gender variation in the immune system and genetics most likely play a role, and their overall results indicate the importance of considering the different anatomies when diagnosing/treating people. 

“Given that there is more variation in human gut anatomy than we thought, this could inform our understanding of what is driving a range of health-related issues and how we treat them,” says Dr. McKenney. “Basically, now that we know this variability exists, it raises a number of research questions that need to be explored.”

“It’s particularly important in medical training, because if students are only learning about a ‘normal’ or ‘average’ anatomy, that means they are not going to be familiar with the scope of human variation,” says Roxanne Larsen, co-author of the paper and an associate professor of veterinary and biomedical sciences at the University of Minnesota. “It’s increasingly clear that the medical field is moving toward individualized medicine to improve patient outcomes and overall health and well-being. Garnering experience in understanding anatomical variation can play a critical role in helping future doctors understand the importance of individualized medicine.”

“We’re excited about this discovery and future directions for the work,” McKenney says. “It underscores just how little we know about our own bodies.”

The small intestine looks like a coil of sausage, and it is longer than the large intestine but has a small diameter. Most of the nutrients from the food we consume will pass through the lining of the small interesting into our blood, and by the time food leaves the small intestine all of its nutrients will have entered the bloodstream leaving indigestible food to be passed from the small intestine to the large intestine for further processing. 

On average men are around 5 feet 9 inches and women are around 5 feet 4 inches. On average, boy's head circumferences are around 2% bigger than a girl’s at birth and the average male brain is 12-20% larger than a girl's. But if you compare, babies of the same size will have similar sizes regardless of sex/gender. Adult men’s brains are on average 10-12% bigger than women’s in weight, and a man’s head is roughly 2% bigger than women’s, but this does not measure intelligence only size which relates to men being larger in general. However, when it comes to guts, women can truthfully say size doesn’t matter.