Protein Power: Decoding the Key to Metabolic Health

The type of food we consume affects our health and longevity throughout our lives, as the phrase "You are what you eat" states. In reality, there is a clear link between age-related nutritional needs and metabolic health. An optimal diet for age can assist preserve metabolic health, hence improving an individual's health span (length of life without diseases) and lifespan. Various dietary therapies involving varying calorie and protein intake have been shown to improve rat and primate health and lifespan. Furthermore, new research has linked dietary macronutrients (proteins, carbs, and fats) to cardiometabolic health and aging in rats. However, the amount of protein required to maintain metabolic health is unknown.

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Protein Requirements for Aging Well

A team of researchers led by Assistant Professor Yoshitaka Kondo of Waseda University, Japan, evaluated the amount of dietary protein required to promote metabolic health in mice approaching old age in a new study published in GeroScience on April 28, 2023 (1^✔ ✔Trusted Source
Moderate protein intake percentage in mice for maintaining metabolic health during approach to old age

Go to source). The researchers enlisted the help of young (6-month-old) and middle-aged (16-month-old) male C57BL/6NCr mice, who were fed isocaloric diets with different protein contents (5-45%) for two months. After two months, the effect of different protein diets was evaluated using skeletal muscle weight measures, liver and plasma lipid profiles, and self-organizing map (SOM) cluster analysis of plasma amino acid profiles.

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Effects of Protein Intake on Metabolic Health

When asked about the motivation behind their study, Assistant Professor Yoshitaka Kondo from Waseda University, Japan, explains, “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 the 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.”

The researchers discovered that consuming a low-protein diet resulted in the development of moderate fatty liver, with higher levels of hepatic lipids in middle-aged mice compared to young animals. A moderate-protein diet, on the other hand, resulted in lower blood glucose concentrations and fat levels in both the liver and the plasma. These results show that a moderate-protein diet (25% and 35%, respectively) preserved both young and middle-aged mice metabolically healthy.

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Link Between Protein Intake, Plasma Amino Acids, and Metabolic Markers

The researchers discovered that the plasma concentration of specific amino acids changed with age and dietary protein content when they investigated the effect of various protein diets on plasma amino acid concentrations in mice of both ages. This was confirmed using SOM analysis of plasma amino acids. Furthermore, the plasma amino acid profiles revealed by SOM analysis demonstrated a link between variable protein intake and varying levels of hepatic triglycerides and cholesterol.

Discussing the impact of their study on public health, Kondo remarks, “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.”

Reference:

1. Moderate protein intake percentage in mice for maintaining metabolic health during approach to old age - (https://pubmed.ncbi.nlm.nih.gov/37118349/)

Source-Medindia