Optimal age-based nutrition improves health and lifespan, study reveals

01 Jun 2023 --- There is a direct association between age-related nutritional requirements and metabolic health, according to researchers at Waseda University, Japan. In their latest study, they purport that “optimal nutrition” based on age can help maintain metabolic health, improving the health span (period of life without diseases) and lifespan.

Calorie and protein intake have improved the health and lifespan in animal experiments and recent studies have shown that macronutrients such as proteins, carbohydrates and fats can boost cardio-metabolic health.

The Waseda University researchers have investigated the amount of dietary protein needed to improve metabolic health approaching old age. The findings were published in GeroScience. The researchers told NutritionInsight they could not comment further "because the findings are in mice and there is no scientific basis in humans."

Recently, Dutch scientists from Wageningen University & Research (WUR), Maastricht University Medical Center (MUMC) and Radboud University Medical Centre (RUMC) made a breakthrough discovery about the health benefits of a personalized diet based on a person’s metabolic profile.

Tweaking protein levels
The Japanese researchers observed that a low-protein diet led to mild fatty liver, with increased levels of hepatic lipids in middle-aged mice compared to young mice. However, moderate protein intake reduced blood glucose concentrations and lipid levels in the liver and plasma. 

The findings suggest that a moderate-protein diet serves as an indicator of improved metabolic health. “The optimal balance of macronutrients for ideal health outcomes may vary across different life stages,” says Yoshitaka Kondo, assistant professor at Waseda University and the study’s lead author.

“Previous studies show the possibility of minimizing age-specific mortality throughout life by changing the ratio of dietary protein to carbohydrates approaching old age. However, the amount of protein that should be consumed to maintain metabolic health is still unclear.”

A moderate protein diet activated in the mature phase of life can improve metabolic health.Dietary proteins provide nitrogen and amino acids for the synthesis of proteins and nitrogen-and amino acid-related compounds in the body. A sustained supply of amino acids maintains tissue and physiological function. 

The experiment
The scientists fed two groups of male mice, young and middle-aged, isocaloric diets with varying protein content (5-45%) for two months. The effect of the diets was assessed based on measurements of skeletal muscle weight, liver and plasma lipid profiles and self‑organizing map (SOM) cluster analysis of plasma amino acid profiles.

The researchers observed that the plasma concentration of individual amino acids varied with age and varying dietary protein content. This was further validated in the SOM analysis. The plasma amino acid profiles showed the correlation between different protein intake and the varying amounts of hepatic triglycerides and cholesterol levels.

“Protein requirements change through the course of life, being higher in younger reproductive mice, reducing through middle age, and rising again in older mice as protein efficiency declines. The same pattern is likely to be observed in humans,” explains Kondo. 

“Therefore, it could be assumed that increasing daily protein intake in meals could promote the metabolic health of people. Ideal dietary macronutrient balance at each life stage could also extend health span. A balanced diet with moderate amounts of protein could be the key to a long and healthy life,” he concludes.

Meanwhile, researchers from the Shanghai Institute of Nutrition and Health of the Chinese Academy of Sciences purport that a high-protein diet and specific antibiotics can prevent weight gain after dieting when most individuals gain weight back. 

By Inga de Jong