Study Suggests Dietary Changes May Make Older Adults Biologically Younger

According to new research from the University of Sydney, older adults who reduced their intake of dietary fat or animal-based proteins demonstrated signs of becoming biologically younger.

The findings, published in Aging Cell, revealed that individuals aged 65 to 75 experienced decreases in their estimated biological age after only four weeks of following specific diets. Researchers believe this implies that adjusting one’s diet later in life might quickly enhance markers associated with aging and overall health.

The study was led by Dr. Caitlin Andrews from the School of Life and Environmental Sciences at the University of Sydney. While the results are encouraging, the researchers pointed out that the study is merely a preliminary indication and not definitive evidence that diet can reverse aging. They noted the necessity for larger and longer studies to ascertain if these biological changes could reduce disease risk over time and whether similar effects occur in other age groups.

Understanding Biological Age

Chronological age counts the years a person has lived, but biological age indicates how well the body is operating. This biological aging can vary greatly among individuals, influenced by health, lifestyle, and resilience against stress and illness.

To determine biological age, scientists evaluate biomarkers—measurable indicators of health over time—which are often seen as more relevant than chronological age for understanding long-term well-being and lifespan potential.

For this study, researchers analyzed data from 20 biomarkers to calculate participants’ biological age scores. These included metrics like cholesterol, insulin, and C-reactive protein levels, sourced from the Nutrition for Healthy Living project at the University’s Charles Perkins Centre.

Examining Four Distinct Diet Plans

The research involved 104 participants who were randomly divided into one of four dietary groups, each contributing 14 percent of their total energy from protein.

Two of the diets were omnivorous, split between half animal and half plant protein, while the other two were semi-vegetarian, with 70 percent of protein from plant sources. Each category included either a high-fat, low-carbohydrate or a low-fat, high-carbohydrate diet. This resulted in four groups: omnivorous high-fat (OHF), omnivorous high-carbohydrate (OHC), semi-vegetarian high-fat (VHF), and semi-vegetarian high-carbohydrate (VHC).

All participants had a BMI between 20 and 35, were non-smokers and non-vegetarians, and did not suffer from major health issues like type-2 diabetes, cancers, renal or liver diseases, or have food allergies or intolerances.

Which Diet Led to the Most Change?

Interestingly, the OHF group, whose diet was closest to their prior eating habits, did not show significant changes in biological age markers.

Conversely, the other three groups displayed reductions in biological age, with the OHC group demonstrating the most substantial statistical evidence. Members of this group followed an omnivorous diet high in carbohydrates and lower in fat, comprising 14 percent of energy from protein, 28-29 percent from fat, and 53 percent from carbohydrates.

Although these results point toward a potential quick impact of diet on biological aging, researchers advise caution, noting that it’s unclear whether these improvements are long-lasting or lead to consistent reductions in biological age.

Call for Extended Research

“Changes to dietary habits over the long term are crucial to determine if these changes actually affect the risk of age-related ailments,” stated Associate Professor Alistair Senior from the School of Life and Environmental Sciences and the Charles Perkins Centre, who supervised the study.

Dr. Andrews commented, “It’s premature to definitively say that specific dietary adjustments will prolong life. Nevertheless, this research highlights the potential advantages of modifying one’s diet later in life. Future studies should investigate if these outcomes apply to other groups and whether the changes documented can be maintained or predict long-term results.”