Some of the earliest clues come from animal experiments. For instance, researchers noticed that mice with oxytocin and oxytocin-receptor deficiencies would later become obese. Correcting these deficiencies, as it turns out, brought their weight went back down to within normal range.
It does seem to make sense though, at least on a gut level. Scientists have long known that feelings of gratification and comfort that come from social interactions can have a significant affect on a person’s eating habits. Interesting enough, the notion of curbing unhealthy eating habits by boosting one’s own personal sense of satisfaction has often been incorporated as an essential tenant of many weight loss treatment plans.
“Patients are not as hungry or inclined to search for food when they’re interested in something or, say, falling in love since the same biological processes that regulate food intake are also involved in social behavior,” explains C. Sue Carter, director of the Kinsey Institute and among the first to describe oxytocin’s role in pair bonding. “We know this, but the biochemical pathways of how this all comes together hasn’t been all that well understood.”
Now, a series of experiments out at Harvard Medical School in Boston may start to shed some light as to why this is.
For their latest study, the researchers tested to see whether administering oxytocin before a meal would result in a reduction in the amount of calories consumed. Thirteen male volunteers of normal weight and 12 who were obese were given either the chemical in the form of a nasal spray or a placebo. The process was later repeated in reverse, with those who received a placebo given the real thing. Of those who took the hormone, they consumed an average of about 122 less calories.
“Our results matched up with pre-clinical studies done in animals, which suggests that oxytocin does indeed work through pathways in the brain that regulate food intake.” says Elizabeth Lawson, an endocrinologist who led the study.
Of course the million dollar question, then, becomes whether these findings can be marshaled into some kind of breakthrough weight loss treatment or product that’s both effective and safe. That’s where much of the research on oxytocin looks to be headed anyway. But given the sobering track record of anything purported to be a cure-all, I wouldn’t bet on it just yet.
The reality is that the “moral molecule,” as some have anointed it, isn’t exactly the miracle worker it’s often made out to be either. Because for as much as it fuels a strong sense of closeness among some, there’s also research that suggests the chemical is just as capable at making people more ethnocentric, closing them off to those outside of one’s own inner circle.
And whereas the huggable hormone was once looked at as a viable treatment for autism, some recent evidence has revealed more of dark side. Mice experiments has shown that, in cases of trauma, elevated levels of oxytocin may actually intensify painful memories, fears and pain.
It’s also possible that oxytocin affects the sexes differently. Researchers at the University of Haifa in Israel observed that women under its influence tended to perceive interactions in friendlier terms while men felt just the opposite, a keener sense of competitiveness.
Going a step further, the medical literature is rife with statistics highlighting the kind of serious, somewhat startling risks associated with taking synthetic hormones. In 2013, investigators at the University of Colorado found that men undergoing replacement therapy for low testosterone had about a one third higher risk of dying, having a stroke or heart attack within next three years. The analysis, which looked at the health records from 8,709 veterans, took into account differences in age and cardiovascular health.
For women taking estrogen, the likelihood of developing breast cancer can shoot up by 43 percent, according to a U.S. government-funded study. Even hormones with milder effects, such as over-the-counter melatonin used for regulating sleep, may produce unpleasant side effects as well and generally isn’t mean’t to be taken regularly for longer than a few months at a time.
“With many of these experiments, you are only seeing the short-term effects of a one-time controlled study,” Carter points out. “That’s very different from taking a chemical like oxytocin over a long period of time, as what would be required if you’re looking at it as a potential therapy for obese or overweight patients.”
Complications tend to arise in instances where the body builds up tolerance or becomes over-reliant on synthetic doses — to the point where it scales down or even shut off its own production. To minimize any potential risks, hormone regimens are usually administered under the careful supervision of a physician.
It’s important to note, though, that oxytocin is categorized as non-toxic. So a single dose is very unlikely to do much harm. It’s also approved by the Food and Drug Administration as Pitocin, but solely as a way to induce contractions during labor.
“We have to be very careful with manipulating hormones, especially the ones likes oxytocin which affect the autonomic system,” Carter says. “It is involved with so many processes, which means many things can go wrong.”
“That’s why it’s imperative that the mechanisms at play are well understood,” she adds.
To that end, Lawson acknowledges that her research team still have a ways to go before they’re able to draw any firm conclusions. She does, however, posit that oxytocin likely influences food intake through a variety of pathways. These include things like altering the hedonic rewards of food or by interacting with other hormones like Ghrelin and Leptin, which help to regulate appetite.
Beyond that, any further speculation would be a tad premature, especially given that the sample size was fairly small and limited to younger men (the average age being 27). On top of this, none reported feeling any changes in appetite or overall satiety. “Right now, we don’t totally know how it works,” she says. “All we know is they just ate less.”
To follow up, Lawson’s team plans to design experiments that look at whether the same results can be achieved with women participants. Another possibility is to peek into the heads of volunteers using an fMRI machine in hopes of identifying certain tell-tale processes that she suspects are taking place deep within the brain.
For now, Carter, who has a background in behavioral science, says she can think of at least one way to realize the fat-burning benefits of oxytocin in a safe and fairly inexpensive manner.
“I may be biased but all this proves is that we respond well to a hormone that our body already does a good job at producing and regulating,” she says. “And the best way will always be to help it make more of its own.”