Breakfast Protein Quality and Muscle Strength in Japanese Older Adults: A Community-Based Longitudinal Study

Dietary characteristics of urban community-dwelling older adults with low muscle mass: the bunkyo health study: a cross-sectional study

BACKGROUND

With the aging of the population worldwide, extending healthy life expectancy is an urgent issue. Muscle mass has been reported to be associated with physical independence and longevity. This study aimed to investigate the characteristics of food intake in urban community-dwelling older adults with low muscle mass.

METHODS

This cross-sectional study used baseline data from the Bunkyo Health Study, which included 1618 urban community-dwelling older adults aged 65-84 years. All participants underwent measurement of body composition using bioelectrical impedance analysis and evaluation of nutrient and food intake using the brief-type self-administered diet history questionnaire. Participants were stratified by sex and divided into robust or low skeletal muscle mass index (SMI) groups according to the Asian Working Group for Sarcopenia criteria to compare differences in nutrient and food intake.

RESULTS

The mean age and body mass index were 73.1 ± 5.4 years and 22.6 ± 3.1 kg/m2, respectively. The prevalence of low SMI was 31.1% in men and 43.3% in women. In men, all food intake, including total energy intake, was similar between the low SMI group and the robust group. In women, the low SMI group had less total energy intake, and consumed lower amounts of energy-producing nutrients (protein, fat, and carbohydrates), but there were only small differences in the intake of specific foods.

CONCLUSIONS

There were sex differences in food intake characteristics between urban community-dwelling older adults with low SMI and those who were robust. Advising women to increase their energy intake may be important in preventing muscle loss, and further research is needed in men.

Association between grip strength and electrical properties measured by bioimpedance spectroscopy in women with dementia aged 77 to 97 years living in group homes

Electrical properties estimated from the electrical resistance of the human body can serve as indicators of muscle tissue status and the risk of developing sarcopenia; however, to date, at least to the best of our knowledge, no studies have performed such an assessment in older individuals with advanced dementia. The present study examined the associations between grip strength, body composition and electrical properties using bioimpedance spectroscopy (BIS) in women aged 77-97 years residing in dementia group homes. A total of 33 participants were enrolled with an average age of 88.1±5.2 years; 57.6% of the participants had moderate or severe dementia. The resistance values of the participants were measured in the whole body, upper limbs and lower limbs using BIS, and their body composition, muscle mass index and electrical properties were estimated as indicators of muscle quality. In addition, grip strength was measured and the participants were classified into three groups (high, low and non-measurable) according to their cognitive function. The effect size (partial eta-squared and Cohen's d) was also evaluated. The Shapiro-Wilk test was used to assess the distribution of each variable; variables with non-normal distributions were analyzed following log transformation. Continuous variables were analyzed using a one-way analysis of variance and the Tukey-Kramer post hoc test was used. The post hoc sample size (statistical power: 1-β) analysis revealed a power of ~80% (i.e., 76.1-88.7%), considering the minimum power for sufficient participants. No differences were found in body composition or muscle mass index among the three grip strength groups. As regards the upper limbs, the electrical properties of the characteristic frequencies were significant (P=0.006; effect size, large), and the membrane capacitance (P=0.005; effect size, large) was significantly higher in the high-dose group than in the other groups. A significant association was detected among grip strength, upper limb characteristic frequency and membrane capacitance. Hence, electrical properties may be an indicator of muscle quality in older women identified as needing care for dementia.

Effect of breakfast protein intake on muscle mass and strength in adults: a scoping review

BACKGROUND

The distribution of protein intake throughout the day is frequently skewed, with breakfast having the lowest protein intake across all age groups. There is no review that addresses the association between breakfast protein intake and muscle mass and strength.

OBJECTIVE

This scoping review aims to summarize the literature on the relationship between protein intake during breakfast and muscle mass and strength in adults.

METHODS

This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. Two independent reviewers screened and appraised the articles identified from 3 electronic databases (Medline, Web of Science, and Scopus) that focused on protein intake per meal and its impact on muscle-related outcomes.

RESULTS

A total of 14 763 articles were retrieved from 3 databases, and after the screening process, 15 articles were included for analysis. Approximately 58.8% of findings from 11 studies examining the association between high protein intake during breakfast and muscle mass indicated an increase in muscle mass among participants. Half of 6 studies (50.0%) exploring the relationship between high protein intake at breakfast and muscle strength demonstrated an increase in muscle strength. Consuming high amounts of protein at breakfast or more protein in the morning than in the evening was associated with an increase in the skeletal muscle index and lean body mass.

CONCLUSION

Protein consumption at breakfast revealed potential benefits in increasing muscle mass across 5 studies involving an elderly population and 2 studies encompassing middle-aged women and young men in our review. However, the relationship between protein intake at breakfast and muscle strength remains unclear. Further high-quality randomized controlled trials are required to examine whether adults can preserve skeletal muscle health outcomes by consuming higher amounts of protein at breakfast.

Association of a lesser number of teeth with more risk of developing depressive symptoms among middle-aged and older adults in Japan: A 20-year population-based cohort study

OBJECTIVES

This 20-year prospective cohort study aimed to longitudinally explore the relationship between the number of teeth and the incidence of depressive symptoms among community-dwelling middle-aged and older adults.

METHODS

Data were collected from the National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA) database from 2002 to 2022 (3rd-9th waves). Data of adults aged ≥40 years were analyzed and those who had depressive symptoms at baseline (3rd wave), had missing data, or did not participate in follow-up, were excluded. We collected data on the number of teeth at baseline. Depressive symptoms were defined as a score of ≥16 on the Center for Epidemiologic Studies Depression Scale. The generalized estimating equation (GEE) model was used to examine the longitudinal relationships between the number of teeth at baseline and the subsequent incidence of depressive symptoms.

RESULTS

The final analysis included 1668 participants, with a mean (standard deviation) age of 58.8 (11.1) years and a mean follow-up time of 12.9 years. After GEE analysis with adjustment for multiple covariates, compared to participants with ≥20 teeth, participants with 10-19 teeth and < 10 teeth at baseline were associated with a higher risk of depressive symptoms. The subgroup analysis showed that the effect was stronger in men than in women.

CONCLUSIONS

Among middle-aged and older community dwellers, particularly men, a small number of teeth after the age of 40 was associated with the future incidence of depressive symptoms.

Fiber-Type Shifting in Sarcopenia of Old Age: Proteomic Profiling of the Contractile Apparatus of Skeletal Muscles

The progressive loss of skeletal muscle mass and concomitant reduction in contractile strength plays a central role in frailty syndrome. Age-related neuronal impairments are closely associated with sarcopenia in the elderly, which is characterized by severe muscular atrophy that can considerably lessen the overall quality of life at old age. Mass-spectrometry-based proteomic surveys of senescent human skeletal muscles, as well as animal models of sarcopenia, have decisively improved our understanding of the molecular and cellular consequences of muscular atrophy and associated fiber-type shifting during aging. This review outlines the mass spectrometric identification of proteome-wide changes in atrophying skeletal muscles, with a focus on contractile proteins as potential markers of changes in fiber-type distribution patterns. The observed trend of fast-to-slow transitions in individual human skeletal muscles during the aging process is most likely linked to a preferential susceptibility of fast-twitching muscle fibers to muscular atrophy. Studies with senescent animal models, including mostly aged rodent skeletal muscles, have confirmed fiber-type shifting. The proteomic analysis of fast versus slow isoforms of key contractile proteins, such as myosin heavy chains, myosin light chains, actins, troponins and tropomyosins, suggests them as suitable bioanalytical tools of fiber-type transitions during aging.

Relationship Between Protein Intake in Each Traditional Meal and Physical Activity: Cross-sectional Study

Background

Protein intake plays an important role in the synthesis and maintenance of skeletal muscles for the prevention of health risks. It is also widely known that physical activity influences muscle function. However, no large-scale studies have examined the relationship between daily dietary habits, especially the timing of protein intake, and daily physical activity.

Objective

The purpose of this cross-sectional study was to investigate how protein intake and composition (involving the 3 major nutrients protein, fat, and carbohydrate) in the 3 traditional meals (breakfast, lunch, and dinner) are associated with physical activity.

Methods

Using daily dietary data accumulated in the smartphone food log app “Asken” and a web-based cross-sectional survey involving Asken users (N=8458), we analyzed nutrient intake and composition, as well as daily activity levels. As very few individuals skipped breakfast (1102/19,319 responses, 5.7%), we analyzed data for 3 meals per day.

Results

Spearman rank correlation analysis revealed that breakfast and lunch protein intakes had higher positive correlations with daily physical activity among the 3 major macronutrients (P<.001). These findings were confirmed by multivariate logistic regression analysis with confounding factors. Moreover, participants with higher protein intake and composition at breakfast or lunch tended to exhibit significantly greater physical activity than those with higher protein intake at dinner (P<.001).

Conclusions

Among the 3 macronutrients, protein intake during breakfast and lunch was closely associated with daily physical activity.