What if the next big thing to boost a healthier, longer life turned out to be — celery?
As scientists research ways to stretch the number of our healthy years, they are increasingly scrutinizing our metabolites, the thousands of molecules produced when our bodies break down the food we eat, the medicines we take, and the sea of chemicals we absorb from our environment.
Teams of researchers, armed with high-tech tools, are deciphering certain patterns of metabolites that may be linked to longer and healthier lives. One of the latest findings comes from an international team led by a Boston scientist that identified metabolites found in celery, parsley, and — in a chocoholic’s dream come true — dark chocolate that may help people age better and live longer.
More specifically, the team found higher levels of flavones, metabolites found in high levels in parsley and celery, and salsolinol, a metabolite in dark chocolate, were present at surprisingly youthful levels in centenarians, suggesting the metabolites might be linked to longevity.
“This is information people can use right now to think about their diet,’’ said lead researcher Paola Sebastiani, director of the Center for Quantitative Methods and Data Science at Tufts Medical Center.
The findings do not mean people should rush out and consume huge quantities of these foods, Sebastiani said. Rather, the research, which is ongoing, points to types of foods, in moderation, that may help with healthy aging.
The research comes as life expectancy in the United States and many other Western nations has increased substantially over the past two decades, but so, too, has the number of years people live burdened by chronic illnesses, such as heart and lung diseases, obesity, and diabetes. Among 183 countries studied recently by researchers at the Mayo Clinic, the United States notched the longest time people live hobbled by such diseases — roughly 12.4 years.
It is that troubling gap that now fuels many scientists’ studies of metabolites, as they hope to clarify the links between these busy molecules that help produce energy in our bodies and health outcomes. Researchers say that understanding the links will help them treat various chronic diseases by pinpointing metabolites that can be manipulated with chemicals, or by lifestyle changes, to produce better health or alleviate illness.
The Tufts-led team analyzed blood samples and other health-related data collected over eight years from a study of roughly 2,700 people, aged mid-20s to 110, all from families with a history of exceptional longevity. The scientists analyzed hundreds of metabolites from the blood samples and identified 19 distinct groups of these molecules, some that change with age, some specifically associated with a higher risk of death, and some that were more plentiful in centenarians.
But the scientists lacked information on the participants’ diets to more closely link their metabolites to their health outcomes. Now, the team is expanding its work, using more detailed information from another large study that includes food diaries from participants, as well as their stool samples.
Researchers say it’s not far-fetched to imagine an annual physical in the not-too-distant future that replaces the blood test that simply measures a few metabolites, such as the amount of glucose, cholesterol, and triglycerides in your system, with a screening that routinely identifies hundreds of metabolites and provides a more complete picture.
“To have a measurement that your cholesterol is below 200 is not enough to say how healthy you are,’’ said Sebastiani, the Tufts researcher.
Susan Sumner, a nutrition professor at the University of North Carolina at Chapel Hill’s Nutrition Research Institute, is looking for “the signature of health [with metabolites] we can use to tell early on if an individual deviates from health and starts going toward a disease state.’’
Sumner and colleagues recently studied more than 400 metabolites in roughly 100 adults. Half of the participants were physically active, not overweight, and ate five or more servings daily of fruits and vegetables and very little red meat. The other 50 were sedentary, overweight, and had poor diets.
The scientists found a distinct pattern of metabolites in the healthy group — a signature of health — that differed from those in the other group. The healthy signature included elevated levels of vitamin D, higher levels of certain beneficial fatty acids, and lower levels of numerous bile acids, which are produced from foods high in saturated fats like meat and certain dairy products.
Sumner is also analyzing the sea of metabolites in an ambitious, $170 million national research project called the Nutrition for Precision Health Study, which is studying thousands of participants with a goal of pinpointing the optimal diet for every person. Tufts and Massachusetts General Hospital are among the study sites.
The latest research into metabolites points to findings that are as promising as they are challenging. For starters, scientists estimate there are more than 150,000 metabolites in the human body and only a fraction have been analyzed. Unlike genes, which are relatively static, metabolites in your body are constantly changing depending on what and when you eat, as well as a host of other daily activities, which is why researchers say they need to study large numbers of people over time, to better distinguish healthy metabolite signatures from unhealthy ones.
“Imagine somebody has an infection, then their metabolism changes. If somebody has a chronic disorder like diabetes, their metabolism changes. If they have any other disorder, or a fever, for example, your metabolism changes. Or you do exercise, your metabolism changes,’’ said Shankar Subramaniam, professor of bioengineering, cellular and molecular medicine at the University of California San Diego.
Subramaniam said metabolites are accessible — easily obtained in saliva and urine as well as blood — and they are powerful markers that are helping provide researchers with a deeper understanding of how the human body works, both in health and in disease.
“We believe this is where the future is going,’’ said Subramaniam, who also is the principal investigator of the National Metabolomics Data Repository, which houses thousands of studies and samples from dozens of countries.
With increasingly more sophisticated tools, researchers are identifying and understanding ever more metabolites. But they say more work is needed to understand how certain foods and diets affect different individuals, based on their genes and their environment.
Still, the idea of using metabolites as medicine, targeting specific nutrients based on scientists’ growing understanding of these molecules, is gaining traction. As Sebastiani, the Tufts researcher, put it: “The idea that there may be some simple interventions based on [metabolites] that could be implemented to help people age well, it is a very exciting thing.’’