Eating a nutritious diet is not only good for reducing the risk of chronic diseases, it may also delay the onset of aging. New rodent research from Japan suggests that modifying your protein intake can have an impact on both…

The saying “garbage in, garbage out” doesn’t just apply to computer applications. Including nutrient-dense food versus calorie-dense food can help prevent metabolic diseases such as diabetes and heart disease and may also increase your lifespan.

Adjusting calorie and protein intake has been associated with better health and longevity in rodents and primates. In addition, new research also suggests a link between macronutrients (carbs, fats and proteins) with cardiometabolic health and aging in mice. But the amount of protein to be eaten for better health is unknown.

A recent study published in GeroScience in April and led by Assistant Professor Yoshitaka Kondo from Waseda University, Japan, evaluated how much protein is necessary to improve metabolic health in mice nearing old age.

The team also included Dr. Takuya Chiba, Faculty of Human Sciences, Waseda University, Dr. Akihito Ishigami, Molecular Regulation of Aging, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Dr. Hitoshi Aoki, Research and Development Division, Nichirei Foods Inc, and Dr. Shin-Ichiro Takahashi, Department of Animal Sciences and Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo.

The research included young (6 months old) and middle-aged (16 months old) male mice. They were fed isocaloric diets with protein content varying between 5% and 45% for two months. The impact of varying protein intake was evaluated after two months based on measurements of skeletal muscle weight, liver and plasma lipid levels, and self-organizing map (SOM) cluster analysis of amino acid profiles in plasma.

Kondo believes, "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."

Kondo’s team noted that the intake of a low-protein diet resulted in the development of mild fatty liver with elevated levels of hepatic lipids in middle-aged mice when compared to young mice. A moderate-protein diet led to lower blood sugar and lipid levels in both liver and plasma. These results suggest that a moderate protein diet (25% and 35%) maintained metabolic health in both young and middle-aged mice.

When reviewing the impact of different protein diets on plasma amino acid concentrations in both age groups of mice, the researchers observed that the plasma concentrations of single amino acids varied with age and varying protein content of the diets. This was also validated using SOM analysis of the plasma amino acids. Using SOM analysis also showed the link between different protein intake and varying amounts of hepatic triglycerides and cholesterol levels.

Kondo believes that, “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 metabolic health of people. Moreover, ideal dietary macronutrient balance at each life stage could also extend health span."

His team believes a balanced diet with moderate amounts of protein may be the key to longevity.

Below are high protein meal ideas;

·         Breakfast burrito with eggs, black beans, and low-fat shredded cheese

·         Cottage cheese and fruit, whole grain toast with nut butter

·         Protein smoothie with mixed fruit, protein powder and Greek yogurt

·         Greek yogurt and fruit with chopped nuts or seeds

·         Quinoa and bean bowl with mixed veggies

·         Tuna salad on whole grain bread with fruit

·         Lentil and rice soup with a side salad (add chick peas or kidney beans to salad)

·         Grilled chicken or fish over greens

Lisa Andrews, MEd, RD, LD

Reference:

1. Yoshitaka Kondo, Hitoshi Aoki, Masato Masuda, Hiroki Nishi, Yoshihiro Noda, Fumihiko Hakuno, Shin-Ichiro Takahashi, Takuya Chiba, Akihito Ishigami. Moderate protein intake percentage in mice for maintaining metabolic health during approach to old age. GeroScience, 2023; DOI: 10.1007/s11357-023-00797-3