In his book Men Are from Mars, Women Are from Venus, written three decades ago, American author John Gray claimed that most common relationship problems between men and women are a result of fundamental psychological differences between the sexes.
Now, it seems that the genders differ even in the way they digest food. A new study conducted at the Faculty of Biotechnology and Food Engineering of Haifa’s Technion-Israel Institute of Technology has discovered significant differences between male and female gastrointestinal tracts that convert food into energy and basic nutrients to feed the body. The researchers concluded that the digestion of milk and milk alternatives is not identical between the sexes.
The findings have just been published in the journal Food Research International under the title “Sex-based differences in in vitro digestibility of milk and oat drink, and powder counterparts.” The research was led by Prof. Uri Lesmes in his Laboratory of Chemistry of Foods and Bioactives, doctoral student Leehen Mashiah, lab manager Dr. Carmit Shani-Levi, and student Eden Beck, who participated in the study while studying for her bachelor’s degree.
Lesmes, who was born in Bogota, Colombia, was brought by his family to Israel in 1982. His grandfather on his mother’s side was from Poland and fled to South America where he attended a small religious Jewish school.
The chemistry researcher told The Jerusalem Post that he has long been fascinated by food.
“The motivation for this research stemmed from the global shift toward plant-based diets and the rise of meat and dairy substitutes,” he said. “Given the growing consumption of these products, we wanted to understand whether men and women derive the same nutritional benefits from them, focusing specifically on milk and milk alternatives. While previous studies have examined digestion in the average adult, few have considered gender differences.”
His lab leads investigations that help lay the scientific and technological foundations that will make possible the fabrication of more healthful food and biotechnological formulations tailored to the needs of the consumer.
They did not test on animals
Unusually, he and his research team of seven master’s and doctoral degree students – who all happen to be women – did not test their theories on rodents. Instead, they developed a unique in vitro digestion model for the study using an advanced bioreactor with sensors, creating a system that knew how to produce conditions like those in male and female humans.
“What exists in animals is not always relevant in people,” Lesmes explained. “In this field, animals are not a good example of the mechanism, so an in-vitro model is much better, even though it isn’t used very much among scientists around the world. Data mining made it possible for us to see the differences between digestion in males and females when we programmed the data in the computer.” The project continued for about five years.
“Human evolution takes a long time, and so does a human generation,” the project leader continued. “Ancient man began to cook meat many hundreds of thousands of years ago.”
THE EARLIEST evidence of ancient humans cooking food dates back about 780,000 years ago and was discovered at the Gesher Benot Ya’aqov archaeological site in Israel. It included the remains of fish teeth that show signs of heating at 500°C, indicating cooking, according to a study published in Nature Ecology and Evolution.
Males usually hunted using bows and arrows, spears, wolves, and dogs. Since women have babies and have to take care of their young, they stayed closer to home.
The results of the researchers’ work were surprising. In the male digestion model, milk proteins were broken down more efficiently, while in the female model, oat-based plant milk showed higher protein digestion efficiency.
The researchers suggested that these findings could correspond with our knowledge of hunter-gatherer societies: Males were the hunters of animals and ate more meat, while females remained closer to home and gathered plants to eat and to prepare for their families. The gastrointestinal system in females therefore broke down oat proteins into amino acids better than milk, contrary to that of males.
Although food was shared within the community, it is likely that men consumed more animal-based products and thus evolved to digest such proteins more efficiently, the team said.
Studies of vegetarianism, said Lesmes, are retrospective and usually look back 20 or 30 years. “Women tended to be vegetarian more than men. But today, things change much faster, and it doesn’t really depend on gender.
“We are in the fourth food revolution: There was fire, domestication, modern food, and today, engineered food – cultured meat or printed meat, chicken, and fish; ‘milk’ without cows, ‘fish’ without fish,” he explained. “Engineered food has been frowned upon by many, because it is very processed, but it’s also more sustainable.”
Lesmes predicted that in the not-too-distant future, people will get a blood test, and food will be prepared by machines/robots for personalized medicine, to prevent diseases. “I hope people will thus eat more healthful diets. Certain insects, for example, including grasshoppers and meal worms, are very nutritious – much more than cows. Insects have a nutty flavor like that in cookies. My lab has been studying them,” he said.
“We will have to find new sources of nutrition to feed everybody and to avoid overburdening the planet. Kashrut is a problem with meal worms but most of humanity doesn’t care about that. Some ice cream is already fortified with worms. Food will also be produced from microalgae and even jellyfish.”
IN-DEPTH analysis revealed differences in the concentrations of amino acids and protein fragments called peptides produced during digestion. In men, more antimicrobial peptides were found; in women, an osteoanabolic peptide linked to bone formation appeared more prominently. These peptides are usually composed from a short chain of amino acids that stimulates the formation of bone by promoting the activity of osteoblasts, which are the cells responsible for building bone. These peptides are being investigated as potential treatments for osteoporosis and other conditions that cause bone loss.
This is particularly interesting because osteoporosis is much more common among older women: one in three women over 50 will experience an osteoporotic fracture, compared to one in five men. This may point to a unique nutritional advantage for women in choosing plant-based protein sources.
The study highlights the impact of biological sex on food digestion and recommends factoring this into nutritional policy, especially future food engineering. “This research aims to optimize nutrition, create gender-specific dietary recommendations and functional foods, improve health outcomes, and promote sustainable food choices by enhancing protein utilization efficiency,” Lesmes said.
“Food processing enabled the rise of modern humans. Our findings suggest consumer biological sex could have significant ramifications to the rational design of future foods and food reformulation efforts,” he concluded. “It’s time to harness research like this for the next phase in food engineering in the 21st century – one rooted in science, nutrition, and health.”