In one of the largest studies to date, researchers from Loma Linda University in California report that vegetarians outlast meat eaters.
Among a group of 70,000 participants, researchers determined that vegetarians had a 12% lower risk of death compared with nonvegetarians. The effect held true for other specific vegetarian diets, according to the study, which is published in the journal JAMA Internal Medicine. For instance, vegans also had a lower risk of death compared to nonvegetarians.
Vegetarian diets have been linked in prior research to a lower likelihood of developing chronic diseases like heart disease or diabetes, but the underlying mechanisms are still under investigation. “We can’t tell from this current paper with certainty, but one of the most plausible potential reasons contributing to this beneficial association is perhaps the absence or reduction of meat intake,” says Dr. Michael J. Orlich, the program director of the preventive-medicine residency at Loma Linda University.
Red meat has been fingered as a potential culprit because of its high levels of saturated fat and cholesterol, which can clog up arteries. In April, another study found that the compound carnitine, also found in red meat, is metabolized by human-gut bacteria and fills up blood vessels.
While there is a fair amount of evidence linking red-meat consumption to higher mortality, other factors could also be at play. “It could also be that consumption of various plant foods may be beneficially associated with reduced mortality, so we definitely want to look at those things on the food level in the future,” says Orlich.
Interestingly, the investigators also found that the association between vegetarian diets and lower mortality was greater in men than in women. Men had a lower rate of cardiovascular disease and death from heart-related conditions. Women did not have the same measurable reductions.
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“I don’t have any strong speculations, but it could be that the diet is playing out differently due to biological factors in men and women,” says Orlich, who plans to look deeper into what specific foods and nutrients may be responsible for the association. Figuring out what drives the link is complex, and it could be different for various groups and individuals. For example, a British study of the vegetarian diet in over 47,250 participants did not find the same mortality results. The fact that American vegetarians consume more fiber and vitamin C could be the reason, and this underscores the need for better understanding of how diet impacts longevity.