By John Salak –
Almost 10 percent of Americans above the age of 18 claim to be vegan or vegetarian—a percentage that is likely growing, according to a report from Alliance For Science. There are all sorts of reasons individuals embrace this lifestyle, including health concerns, religious convictions, animal welfare issues and even to support a healthier environment.
However, there may be another reason why some forego meat and are able to stick to the related dietary restrictions. They may be influenced by their genetic make-up. At least this is what researchers from Northwestern University claim.
The university’s study doesn’t dismiss the noble intentions or health concerns that motivate individuals to embrace a vegan or vegetarian lifestyle. Rather, its work focused on why it seems so difficult for so many of these people to actually go without meat for extended periods.
“Are all humans capable of subsisting long-term on a strict vegetarian diet? This is a question that has not been seriously studied,” noted corresponding study author Dr. Nabeel Yaseen, professor emeritus at Northwestern. It is particularly relevant because almost two-thirds of self-identified “vegetarians” report eating fish, poultry and/or red meat at times. Yaseen suggests environmental or biological constraints may override their desire to adhere to a vegetarian diet.
“It seems there are more people who would like to be vegetarian than actually are, and we think it’s because there is something hard-wired here that people may be missing,” he added.
The Northwestern team worked to tackle this issue by comparing the genetic data from more than 5,000 strict vegetarians (no fish, poultry or red meat) to those of a control group of almost 330,000 individuals. All study participants came from the UK Biobank and were Caucasian.
The research ultimately identified three genes that are significantly associated with vegetarianism and another 31 genes that are potentially associated. Several are involved in lipid (fat) metabolism and/or brain function.
“One area in which plant products differ from meat is complex lipids,” Yaseen said. “My speculation is there may be lipid components present in meat that some people need. And maybe people whose genetics favor vegetarianism are able to synthesize these components endogenously. However, at this time, this is mere speculation and much more work that needs to be done to understand the physiology of vegetarianism.”
The results come against some gaps between intentions and actions. For example, despite compelling religious, moral and health reasons for adopting a vegan or vegetarian diet, the researchers pointed out that the percentage of people embracing this lifestyle, while perhaps growing, still remains relatively small. This begs the question as to why most people still prefer to eat meat products.
Taste may be one factor, but not the only one. Yaseen speculates that another issue is how an individual’s body metabolizes food. He cites how people usually react when first trying coffee or alcohol. They usually don’t like it but over time they develop a taste for it because it makes them feel good.
“I think with meat, there’s something similar,” Yaseen explained. “Perhaps you have a certain component—I’m speculating a lipid component—that makes you need it and crave it.”
The university’s findings, however, don’t lessen the initial motivation for those who don’t eat meat for religious or moral reasons, just their ability to stick with the approach, he stressed.
“While religious and moral considerations certainly play a major role in the motivation to adopt a vegetarian diet, our data suggest that the ability to adhere to such a diet is constrained by genetics,” Yaseen said. “We hope that future studies will lead to a better understanding of the physiologic differences between vegetarians and non-vegetarians, thus enabling us to provide personalized dietary recommendations and to produce better meat substitutes.”