The types of food that we eat influence our health and longevity from the time we are born all the way through our time on this planet. There is a direct association between age-related nutritional requirements and metabolic health, and maintaining optimal nutrition according to age can help maintain metabolic health improving both healthspan and lifespan.
Nutritional interventions involving varied calorie and protein intake are known to improve health and lifespan or rodents and primates, and recent studies have reported the association of dietary macronutrients with cardiometabolic health in aging mice, however, the amount of protein required to maintain metabolic health is not known.
For this study 6-month-old mice (young) and 16-month-old mice (middle-aged) were fed isocaloric diets with varying protein content of 5-45% for two months, after that, the effects of varying protein diets were assessed based on measurements of skeletal muscle weight, liver and plasma lipid profile, and self-organizing map cluster analysis of plasma amino acid profiles.
The researchers reported that consumption of a low protein diet was observed to lead to the development of mild fatty liver with increased levels of hepatic lipids in the middle-aged mice compared to the young mice, while consumption of a moderate protein diet was observed to lead to reduced blood glucose concentrations and lipid levels in both liver and plasma. Findings indicate that a moderate protein diet kept both young and middle ages mice metabolically healthier at 25% and 35% respectively.
Plasma concentrations of individual amino acids were observed to have varied with age and varying dietary protein content, which was validated using SOM analysis of plasma amino acids. Plasma amino acid profiles revealed using SOM analysis showed the correlation between different protein intake and the varying amounts of hepatic triglycerides and cholesterol levels.
“The optimal balance of macronutrients for ideal health outcomes may vary across different life stages. Previous studies show the possibility of minimizing age-specific mortality throughout life by changing the ratio of dietary protein to carbohydrates during approach to old age in mice. However, the amount of protein that should be consumed to maintain metabolic health while approaching old age is still unclear,” said Assistant Professor Yoshitaka Kondo from Waseda University, Japan.
“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. Therefore, it could be assumed that increasing daily protein intake in meals could promote the metabolic health of people. Moreover, ideal dietary macronutrient balance at each life stage could also extend health span,” said Kondo.
The researchers concluded that a balanced diet with moderate amounts of protein could be the key to a long and healthy life.
