MADRID, June 28 (EUROPA PRESS) –

While millions of people look for ways to stay active for longer, experts are trying to answer an increasingly relevant question: how to gain years of life without giving up strength, mobility and autonomy. A new work provides unexpected clues on this question.

Can we maintain that longevity and, at the same time, reach older ages with more strength and less metabolic disease? New research is trying to answer this question by looking much more closely at what we actually eat and how certain nutrients may influence aging.

LESS PROTEIN, MORE VITALITY: THE PARADOX OF SOUTHERN EUROPE

A low-protein, plant- and fish-based diet, combined with small amounts of an amino acid commonly found in eggs, meat and dairy products, increased healthy lifespan and decreased frailty and fat mass in mice, according to a new USC study published in the journal Cell Metabolism.

Researchers compared a high-fat, high-sugar Western diet, a low-carbohydrate ketogenic diet, a diet inspired by traditional Mediterranean and Okinawan patterns supplemented with methionine, and periodic cycles of a fasting-mimicking diet to analyze which best supported healthy longevity and physical endurance during aging.

The researchers, led by Valter Longo of the USC Leonard Davis School of Gerontology, also collaborated with colleagues at the University of Toronto (Canada) and Harvard University (United States) to analyze existing data on the diet and health of more than 200,000 people. The team found similar health benefits associated with a more plant-based diet, such as a lower incidence of obesity and type 2 diabetes.

According to Longo, the combined data from mice and humans indicate that the best health results can be obtained by following a “longevity diet” that is mostly vegan or vegetarian, but with the addition of fish. This Mediterranean-inspired diet provides a small but sufficient amount of methionine and other essential amino acids.

Longo has extensively studied the relationship between diet, health and longevity. Much of his work has focused on the Mediterranean dietlow in protein and plant-based, a mainstay of the long-lived populations of southern Europe.

Although these groups have one of the highest life expectancies in the world, they also have high rates of fragility. Because plant foods contain lower amounts of essential amino acids than animal products, Longo developed a longevity diet supplemented with a small amount of the essential amino acid methionine to evaluate its effects on frailty risk.

For the experiment, groups of 20-month-old mice were fed one of four diets: a standard diet; a Western diet rich in fats and sugars; a low-carb ketogenic diet; or the low-protein longevity diet supplemented with methionine (LDMM). Mice receiving LDMM showed significantly better outcomes, including longer healthy lifespan (the part of life spent in good health), lower fat mass, and reduced frailty.

“We expected that different diets would produce different results, but what really impressed us was how the modulation of a single amino acid, methionine in the longevity diet could generate such drastic metabolic changes,” said Maura Fanti, a research associate at USC Leonard Davis and first author of the new study.

“This suggests that amino acid composition, and not just the total amount of protein, could be the target of strategic metabolic interventions,” he notes.

Besides, Testing revealed several biomarkers of better cardiometabolic health in LDMM miceincluding higher amounts of signaling molecules that affect metabolism and aging in different species, such as GLP-1, according to Fanti.

Of course, the expert clarifies, “there are differences in the way these pathways are regulated between mice and humans, but observing such coordinated changes in multiple metabolic hormones is really encouraging, and we are very curious to know if effects of similar magnitude would be observed in studies with humans.”

Longo points out that one of the most notable findings was that mice on the LDMM diet could eat more than any other group and consume as many calories as any other group, and still lose fat without losing lean muscle mass, but only when methionine levels were low but sufficient.

OPENS NEW QUESTIONS ABOUT PROTEINS AND DIABETES

Additionally, human data showed that participants who consumed the highest levels of animal protein (and therefore the greatest amount of methionine and other essential amino acids) had a higher prevalence of obesity and double the risk of diabetes compared to those who consumed little or no animal protein. This held true even when those who consumed more animal protein had lower caloric intake and overall healthier nutrition.

“This challenges the dogma that calorie reduction is necessary to lose weight, but it also tells us that we must clearly understand the mechanisms,” Longo said.

“Insufficient methionine intake caused frailty, while too much methionine negated the benefits of this diet, which was otherwise based on feeding long-lived populations such as the traditional Italian and Okinawan diets. These results indicate that total protein intake may be less important than the intake of specific amino acids,” he adds.