Explore how a nutrient-dense plant-based diet supports physical performance and fights age-related decline.
Study: Plant-based diets and their associations with physical performance in the Baltimore Longitudinal Study of Aging. Image credit: MarinelaM / Shutterstock
A recent study published in the journal Nutrients evaluated associations between plant-based diet and physical performance in an aging population.
Physical performance is crucial for promoting healthy aging and mitigating the risk of disability and morbidity in older adults. Physical performance is often measured through handgrip strength, balance, mobility, and lower body strength, which are related to skeletal muscle mass, function, and strength.
Age-related declines in muscle strength and mass typically begin in adulthood and accelerate with aging. Muscle mass declines by 1% to 3% per year, while muscle strength declines by 2.5% to 4% per year. Malnutrition and wasting can exacerbate these declines. Diets play an important role in supporting muscle health and ameliorating age-related declines in physical performance.
Dietary patterns characterized by plant-based foods have been associated with enhanced physical strength and function in older adults. While the health benefits of a plant-based diet for diabetes, cancer, and cardiovascular disease are well documented, their effects on physical performance and function, especially in older individuals, have been less studied. However, recent findings highlight that the quality of plant foods significantly influences their impact on physical performance.
About the study
The present study investigated the relationship between a plant-based diet and physical performance in an aging population. They obtained data from the Baltimore Longitudinal Study of Aging (BLSA), which began in 1958. Participants were recruited from the Baltimore-Washington area in the United States (US). Laboratory tests, interviews, and clinical examinations were performed during follow-up assessments.
In addition, the BLSA began collecting dietary data in 2005 using a semiquantitative food frequency questionnaire. This study analyzed data collected from 2015 to 2018. Participants with missing data or energy intake < 600 kcal/ημέρα ή > 4800 kcal/day were excluded. Adherence to a plant-based diet was assessed by the total plant-based diet index (PDI), healthy PDI (hPDI) and unhealthy PDI (uPDI).
These indicators included 18 food groups: seven were healthy plant-based foods, five were unhealthy plant-based foods, and six were animal-based. Indicators were scored and stratified into tertiles (T1:T3), with T3 indicating higher adherence to the diet. The Small Physical Performance Battery (SPPB) was used to examine physical function. Grip strength was assessed using a Smedley hand dynamometer. Walking speed was measured at a fixed distance (6 meters).
Covariates included age, race/ethnicity, sex, education, smoking status, physical activity, body mass index (BMI), chronic diseases, average energy intake, and alcohol consumption. Analysis of covariance and the chi-square test were used to examine differences in sample characteristics between third parties. Associations between adherence to a plant-based diet and grip strength, walking speed, and SPPB were assessed using multivariable linear regression models.
The researchers also conducted sensitivity analyzes among participants aged ≥65 years to strengthen the findings.
Findings
The study included 1,398 participants with valid FFQ data. Their baseline age was 68.3 years, on average. Most participants were female (53.2%) and non-Hispanic White (72.3%). About 23.4% were obese and 38.7% were overweight. Older age was associated with higher hPDI and PDI but not uPDI. In addition, higher PDI rates were associated with greater consumption of whole grains, fruits, vegetables, beans, nuts, and vegetable oils.
Higher PDI tertiles were also associated with greater intake of unhealthy foods such as sugary drinks, sweets and juices. Individuals in the highest tertile of hPDI had significantly increased intake of healthy food groups and decreased intake of less healthy food groups relative to those in the highest tertile of high food index. Consumption of fish, seafood, lard and eggs was comparable between uPDI and hPDI tertiles.
In addition, SPPB and walking speed did not differ between PDI tertiles. However, participants in the highest hPDI trimester had higher SPPB scores and walking speed, while those in the highest uPDI trimester showed lower SPPB scores. Participants in the highest PDI triangle had significantly lower grip strength. There were no significant correlations between physical performance and total PDI.
However, hPDI was positively correlated with physical performance measures, while uPDI was negatively correlated. For example, participants in the highest hPDI tertile had grip strength values 1.14 kg higher than those in the lowest tertile, highlighting the importance of nutrient-dense foods. A sensitivity analysis restricted to a subsample of subjects aged ≥65 gave results consistent with the primary analysis. Higher adherence to a healthy plant-based diet was associated with higher grip strength and SPPB in this subsample.
conclusions
The findings reveal that overall adherence to a plant-based diet did not significantly improve physical performance in a group of middle-aged and older adults. However, following a healthy plant-based diet was associated with physical function and strength. Conversely, an unhealthy plant-based diet was negatively associated with physical functioning. These results emphasize the need to prioritize the quality of plant foods in dietary recommendations.
Further studies are needed to confirm these results, reveal mechanisms, and refine dietary recommendations to optimize plant-based diets for aging populations. Additionally, future research could investigate how specific plant nutrients, such as antioxidants and short-chain fatty acids, contribute to physical performance and muscle health.
