New research from the University of Sydney shows older Australians who reduce either dietary fat or animal protein show signs of decreasing biological age.
Published in aged cellsthe results revealed that people aged 65 to 75 who received just four weeks of dietary intervention showed a decline in their ‘biological age’ based on their biomarker profiles. The study, led by Dr Caitlin Andrews from the School of Life and Environmental Sciences at the University of Sydney, highlights the potential for dietary interventions to rapidly improve health and aging outcomes in older people. This provides a preliminary indication rather than a final result, and the authors call for long-term trials to test whether these improvements translate into reduced disease risk and whether the results extend to other age groups.
Although chronological age increases uniformly, biological aging varies from person to person, reflecting differences in health status and the body’s ability to recover. Scientists can estimate biological age using biomarker profiles, which are measures of physiological function over time. Biomarker profiles are considered a better indicator of overall health and potential longevity than chronological age.
The study combined data from 20 different biomarkers, including blood levels of cholesterol, insulin, and C-reactive protein, to calculate biological age scores for participants in the Nutrition for Healthy Living study conducted at the university’s Charles Perkins Center.
In the “Nutrition for Healthy Living” study, 104 participants were randomly assigned to one of four diets, each with 14 percent of their energy coming from protein. Two were omnivores (half of their protein came from animals, the rest came from plants), and two were semi-vegetarians (70% of their protein came from plants). Within the omnivorous and semi-vegetarian categories, participants were assigned to either a high-fat, low-carbohydrate or low-fat, high-carbohydrate diet, resulting in four dietary categories: omnivorous high-fat (OHF), omnivorous high-carbohydrate (OHC), semi-vegetarian high-fat (VHF), or semi-vegetarian high-carbohydrate (VHC).
Participants’ body mass index (BMI) ranged from 20 to 35. All participants were non-smokers, non-vegetarians, and had no serious comorbidities (e.g. type 2 diabetes, cancer, kidney or liver disease) or food allergies and/or intolerances.
The OHF group, whose modified diet most closely resembled participants’ baseline diet, showed no significant change in ‘biological age’ in biomarker profile. However, the biological age of the remaining three groups’ biomarker profiles showed a decrease. The decrease in biological age in the OHC group (the group fed an omnivorous diet high in carbohydrates) was estimated with the highest statistical confidence. This group’s diet consisted of 14 percent of its energy from protein, 28 to 29 percent from fat, and 53 percent from carbohydrates.
It is unclear whether the effects of dietary changes on age-related biomarker profiles are permanent and result in sustained biological age reversal.
Long-term dietary changes are needed to assess whether dietary changes change the risk of age-related diseases. ”
Alistair Senior, Associate Professor, Faculty of Life and Environmental Sciences and Charles Perkins Center
“It is too early to say definitively that specific changes in diet will extend lifespan, but this study provides an early indication of the potential benefits of dietary changes later in life,” Dr. Andrews said.
“Future studies should investigate whether these findings extend to other cohorts and whether the changes recorded persist or predict long-term outcomes.”
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Reference magazines:
Andrews, C.J.; Others. (2026). Short-term dietary interventions alter physiological profiles associated with aging. aged cells. DOI: 10.1111/acel.70507. https://onlinelibrary.wiley.com/doi/10.1111/acel.70507
