Can your diet and gut microbiome be the key to healthy aging?

People who eat diets rich in fruits, vegetables, whole grains, and healthy fats are more likely to experience healthy ageing

Recent studies found that higher adherence to eight specific dietary patterns is associated with a greater probability of healthy aging. The strongest link was observed for the “Alternative Healthy Eating Index” (AHEI) where participants, when using a 70-year cutoff, with the highest adherence had up to 86% greater odds of aging healthily compared to those with the lowest adherence. When the age threshold was raised to 75 years, odds increased 2.24 times.

In this landmark study published in Nature Medicine, scientists analyzed data from over 105,000 participants, over three decades (ages ranging from 39 to 69). The eight dietary patterns studied included: AHEI, Alternative Mediterranean Index (aMED), the Dietary Approaches to Stop Hypertension (DASH), the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), the Healthful Plant-based Diet (hPDI), the Planetary Health Diet Index (PHDI), the Empirically Inflammatory Dietary Pattern (EDIP), and the Empirical Dietary Index for Hyperinsulinemia (EDIH). The researchers assessed adherence to these eight dietary patterns and their association with healthy aging.

Healthy aging was defined as reaching at least 70 years of age, without any of 11 major chronic diseases (including all cancers except for non-melanoma skin cancers, diabetes, myocardial infarction, coronary artery disease, congestive heart failure, stroke, kidney failure, chronic obstructive pulmonary disease, Parkinson disease, multiple sclerosis, and amyotrophic lateral sclerosis), while maintaining intact cognitive, physical, and mental health.

These associations were independent of other lifestyle factors such as physical activity level, smoking, and body mass index (BMI). A higher intake of fruits, vegetables, whole grains, unsaturated fats, nuts, legumes, and low-fat dairy products—as reflected in the AHEI diet—was linked to better physical function and mental health. The PHDI was most strongly associated with intact cognitive health and reaching the age of 70, while the rEDIH was most closely associated with being free of chronic diseases. Conversely, higher consumption of trans fats, sodium, sugary beverages, and red or processed meats—characteristic of Ultraprocessed Foods—were associated with poorer health outcomes.

Could the microbiome drive the benefits of calorie restriction on aging?

While the human study highlighted the importance of long-term dietary patterns for healthy aging, another research group explored how dietary interventions affect the gut microbiome and aging in mice.

Analyzing nearly 3,500 stool samples from 913 mice, the researchers tracked microbiome changes over time under various dietary restriction regimens, including caloric restriction and intermittent fasting. They found that aging was consistently associated with increased microbiome uniqueness—a measure of how distinct an individual’s microbial profile is compared to others. This trend was also observed in a large dataset of over 4,000 human metagenomes, suggesting that microbiome uniqueness may be a universal hallmark of aging across species.

These results support earlier findings on aging and survival related to the human gut microbiome. For instance, Wilmanski’s research group studied this link in individuals aged 18 to 101 years and found that, starting in mid-to-late adulthood, healthier individuals exhibited a steady shift toward a more unique gut microbiome. This shift was linked to specific microbial byproducts found in the blood and a decline in common bacteria like Bacteroides.

Interestingly, dietary restriction in mice did not revert the microbiome to a more youthful state. Instead, it led to distinct microbial shifts, particularly in genera such as Ligilactobacillus and Lactobacillus, and increased some of their key functions, such as the production of amino acids like lysine and components of the bacterial cell wall.

Moreover, researchers also investigated whether the microbiome directly modulates host health and aging. They found that the microbiome was associated with several health parameters, including body composition, immune function, and frailty, though not with lifespan itself. Specifically, certain gut microbes and their metabolic activities were linked to traits such as body fat and lean mass, immune cell markers, and signs of physical decline. This suggests that while the microbiome may help regulate aspects of health span, its role in determining longevity remains unclear.

How close are we to tailored healthy aging recommendations?

Despite their strengths, both studies have limitations. The human study relied on self-reported dietary data and questionnaires to assess various health domains, which may introduce bias. The animal research, while offering deeper mechanistic insights, was conducted in mice, which may not fully reflect human biology.

Future research should aim to integrate microbiome profiling into human aging studies, exploring how specific microbial taxa and metabolites mediate the effects of diet on aging. For instance, the role of dietary fiber—known to influence microbial diversity and the production of short-chain fatty acids (SCFA)—warrants further investigation as a potential modulator of human health and aging. A deeper understanding of these links could help prevent or reduce frailty and promote healthier aging.

Takeaway

Together, these studies underscore the importance of diet in shaping aging outcomes—both through direct nutritional effects and by modulating the gut microbiome. Diets rich in fruits, vegetables, whole grains, unsaturated fats, nuts, legumes, and low-fat dairy products have consistently been associated with better aging outcomes, helping maintain physical strength, mental well-being, and cognitive sharpness. At the same time, research indicates that a more “unique” gut microbiome—one that gradually shifts away from common patterns with age—is linked to healthier aging and increased survival.

Although science is still uncovering the full role of the microbiome in human health and aging, one thing is becoming increasingly clear: we already possess powerful tools to influence how we age. Choosing nutritious foods, staying active, avoiding harmful habits, and supporting our gut health can have real, lasting impacts on our quality of life as we grow older.

References

Tessier AJ, Wang F, Korat AA, et al. Optimal dietary patterns for healthy aging. Nature Medicine. 2025;31:1644–1652. DOI: 10.1038/s41591-025-03570-5.
Litichevskiy L, Considine M, Gill J, et al. Gut metagenomes reveal interactions between dietary restriction, ageing and the microbiome in genetically diverse mice. Nature Microbiology. 2025;10:1240–1257. DOI:10.1038/s41564-025-01963-3.
Wilmanski T, Diener C, Rappaport N, et al. Gut microbiome pattern reflects healthy ageing and predicts survival in humans. Nature Metabolism. 2021;3(2):274-286. DOI: 10.1038/s42255-021-00348-0
Kabisch S, Hajir J, Sukhobaevskaia V, et al. Impact of Dietary Fiber on Inflammation in Humans. Int J Mol Sci. 2025;26(5):2000. DOI: 10.3390/ijms26052000.
Lim MY, Nam YD. Gut microbiome in healthy aging versus those associated with frailty. Gut Microbes. 2023;15(2):2278225. DOI: 10.1080/19490976.2023.2278225.

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