Just four weeks after switching to a diet rich in whole-food complex carbohydrates and plant-based foods, aging-related biomarker profiles changed in older adults. But scientists say this change may reflect rapid physiological adaptation rather than a true age reversal.
Research: Short-term dietary interventions alter physiological profiles associated with aging. Image credit: Wuttichok Panichiwarapun/Shutterstock.com
Short-term dietary interventions can alter age-related physiological changes in older adults, as reported in a new study published in . aged cells.
How diet shapes physiological aging
Aging is a multifactorial biological process characterized by complex molecular, cellular, and physiological changes. This inevitable biological process is usually associated with poor health and increased risk of illness and death.
Chronological age, the exact time elapsed since birth, is considered the real age of a person, increasing uniformly over time. Biological age, on the other hand, is considered a functional age that accurately indicates a person’s health status and mortality risk, regardless of their chronological age.
Unlike chronological age, biological age varies widely between individuals and is influenced by several modifiable factors, such as diet and physical activity. Diet is one of the important modifiable determinants that may modulate age-related biomarker profiles. In this context, evidence shows that animal-based and plant-based foods have different effects on biomarkers associated with key aging markers such as inflammation and oxidative stress.
Studies investigating the health benefits of different dietary patterns have shown that macronutrients such as protein, carbohydrate, and fat may differentially modulate age-related biomarkers and physiological profiles, highlighting the need for more detailed studies to investigate beneficial changes in age-related biomarkers across dietary patterns.
Researchers at the University of Sydney in Australia recently used the Kremera-Douval method (KDM) to investigate the effects of a short-term dietary intervention on the age-related physiological state of older adults. This method estimates age-related physiological status by integrating a set of blood and clinical biomarkers that are known to vary systematically with chronological age at the population level.
The difference between chronological age and KDM-generated age, which is commonly used as a proxy for biological age, represents the degree to which a person’s biomarker profile matches or deviates from typical expectations for age. A lower value indicates a better match to the typical physiological profile for that person’s age. Positive values indicate that the physiological profile is older than expected, and negative values indicate a healthier or more resilient physiological state.
Comparing carbohydrate and fat ratios in a 4-week trial
Researchers used the KDM algorithm to analyze data from the Nutrition for Healthy Living Study (NHL). NHL was a randomized dietary trial in 104 older adults aged 65 to 75 years.
Participants were randomly assigned to one of four dietary interventions: animal-based high-fat, animal-based high-carbohydrate, semi-vegetarian high-fat, and semi-vegetarian high-carbohydrate.
The difference between chronological age and KDM-generated age (used here as a proxy for biological age or age-related physiological state) was measured at baseline (before the start of the intervention) and after the 4-week intervention period.
Plant-forward diet altered age-related biomarker profiles
Analysis of the studies revealed that a 4-week dietary intervention had a measurable impact on KDM-derived physiological age profiles in older adults.
Specifically, this study found no significant changes in KDM-derived age profiles among participants consuming an animal-based high-fat diet. In contrast, participants who consumed an animal-based high-carbohydrate diet, a semi-vegetarian high-fat diet, or a semi-vegetarian high-carbohydrate diet showed a reduced KDM-derived age profile compared to the animal-based high-fat group.
This reduction was statistically significant among participants who consumed an animal-based, high-carbohydrate diet. Participants on the semi-vegetarian high-fat diet showed a statistically significant reduction in one KDM measure, whereas participants on the semi-vegetarian high-carbohydrate diet showed a statistically non-significant reduction.
Rapid response of dietary biomarkers
This study highlights the potential impact of short-term dietary interventions on KDM-derived age, which is widely used as a surrogate for biological age in large epidemiological cohorts. This finding also supports the utility of KDM-derived age for assessing age-related changes in physiological status in older adults.
However, the researchers advised that these findings be considered with caution as evidence of biological age reversal or delay, as the observed changes may reflect acute physiological responses to dietary components rather than changes in aging trajectories.
Age-related biomarkers considered in KDM are influenced by metabolic, cardiovascular, and inflammatory conditions. Because these conditions are highly sensitive to short-term dietary changes, it remains possible that the observed changes are an acute physiological response rather than a reversal of age-related dysfunction. The researchers emphasized that this study was not designed to determine whether the observed changes represent a true slowing of biological aging or simply a short-term adaptive physiological response to dietary intake.
Future studies with longer intervention and follow-up periods are therefore needed to assess whether the observed decrease in KDM-derived age measurements in response to dietary changes persists after the intervention period or predicts long-term outcomes.
The dietary intervention tested in this study has also been investigated in several other studies. The results of these studies show that these diets, especially rich diets, Whole food complex carbohydrates are associated with increased lifespan, improved metabolic health, and reduced risk of chronic disease across species. The carbohydrates used in these meals come from minimally processed whole sources and should not be confused with refined or simple carbohydrates, which can induce different metabolic effects.
Previous studies analyzing data from the NHL trial have shown that these diets were substantially different from the participants’ habitual diet, with the exception of the animal-based high-fat diet, which most closely resembled the participants’ habitual diet and showed no change in KDM-derived age measurements after the intervention period.
The participants’ habitual diets closely resembled the typical Australian diet, which is rich in refined sugar, saturated fat, and processed foods. The lack of beneficial changes after this dietary intervention was consistent with extensive evidence linking Western dietary patterns to metabolic deterioration.
The NHL study population considered in this study represents a relatively healthy subpopulation with greater physiological resilience compared to age norms. At baseline, participants already exhibited negative KDM-derived age values on average, indicating a relatively resilient physiological profile. This may limit the generalizability of our findings to other populations with suboptimal health status. Future studies with more diverse cohorts are needed for further validation.
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