By Heather Davis, MS, RDN, LDN
The wear and tear delivered by time’s passing seems inevitable. Although none are wholly immune, dietitians know that the difference between a patient’s aging gracefully and suffering needlessly from preventable degenerative chronic disease during the second half of life may largely be attributed to lifestyle factors like nutrition. Diet is the first leading behavioral risk factor for noncommunicable diseases and mortality burden globally, and the second after tobacco use in US older adults.1
What does it really mean to “age gracefully”? The World Health Organization (WHO) defines healthy aging as “the process of developing and maintaining the functional ability that enables well-being in older age.” The WHO says that functional ability is about having the capabilities that enable all people to be and do what they have reason to value. This capacity comprises all the mental and physical capacities that a person can draw on and includes their ability to walk, think, see, hear, and remember.2 Behind each of these important capacities is a biochemical engine, churning day after day and relying on quality nutrition input.
Much emphasis is rightly placed on the importance of early life nutrition in guiding lifelong health outcomes. However, choices and circumstances throughout life continue to inform and direct those outcomes, and new research encourages us to focus on midlife as a key time for setting the stage for healthy aging.
A New Study Offers Clarity
A study published in Nature in May of this year used data from the Nurses’ Health Study and the Health Professionals Follow-Up Study to examine the midlife diets and eventual health outcomes of more than 105,000 women and men aged 39 to 69 over the span of 30 years. Dietary questionnaires were regularly completed by participants and then used by the researchers to calculate scores based on how well participants adhered to eight healthy dietary patterns: the Alternative Healthy Eating Index (AHEI), the Alternative Mediterranean Index, the DASH diet, the Mediterranean-DASH Intervention for Neurodegenerative Delay, the healthful plant-based diet, the Planetary Health Diet Index, the empirically inflammatory dietary pattern, and the empirical dietary index for hyperinsulinemia. Each of these diets emphasizes high intake of fruits, vegetables, whole grains, unsaturated fats, nuts, and legumes, and some also include low to moderate intake of animal-based foods such as fish, some meat, and certain dairy products. The researchers also assessed participants’ intake of ultraprocessed foods, noted for containing higher amounts of added sugars, sodium, and unhealthy fats.1
Where previous studies had investigated dietary patterns in the context of certain diseases associated with aging, this study took a slightly different approach by broadening the view to encompass the impact of nutrition on overall quality of life as one ages. With a definition of healthy aging in line with the WHO’s description, researchers asked how dietary patterns—particularly at midlife—impact one’s ability to live independently and with good functionality in later life.
The Insights
The study found that only 9,771 participants—9.3% of the study population—aged healthfully. Other findings include the following:
- In the pooled cohorts, 39,769 (37.9%) reached the age of 70 years;
- 23,908 (22.8%) remained free of 11 chronic diseases;
- 35,555 (33.9%) maintained intact cognitive function;
- 29,543 (28.1%) maintained intact physical function; and
- 27,842 (26.5%) maintained intact mental health.
Adhering to any one of the eight healthy dietary patterns was linked to overall healthy aging and its individual domains, including cognitive, physical, and mental health. Maintaining a diet rich in plant-based foods, low to moderate intake of animal-based foods like fish, and lower intake of ultraprocessed foods was linked to a higher likelihood of healthy aging. The diet showing the most promise in supporting healthy aging was the AHEI. Participants in the highest quintile of the AHEI score had an 86% greater likelihood of healthy aging at 70 years and a 2.2-fold higher likelihood of healthy aging at 75 years compared with those in the lowest quintile of the AHEI score. The AHEI diet is rich in fruits, vegetables, whole grains, nuts, legumes, and healthy fats, with moderate intake of animal products like fish and some dairy. It’s low in red and more processed meats, sugar-sweetened beverages, sodium, and refined grains.1
Higher intake of ultraprocessed foods, especially processed meat and sugary and diet beverages, was associated with lower chances of healthy aging.1
Considerations for RDs
Both intervention and observational studies have provided strong evidence that quality nutrition is beneficial for the prevention of CVD, type 2 diabetes, and premature mortality. Nutrition also plays an important role in age-related cognitive and physical performance outcomes and mood.1 While observational or correlational studies lack the power to determine direct cause-and-effect relationships more evident in experimental or intervention studies, they nonetheless provide valuable data, some of which helps shape future randomized controlled trials (RCTs). Additionally, there are sometimes ethical reasons why observational studies may be preferable to RCTs. For example, study designs meant to better confirm the findings and direction of causation might require 50% of participants to eat a known unhealthy diet for many years, while the other 50% of participants consume an AHEI dietary pattern. This may knowingly expose a significant percentage of participants to ill health effects. Even so, it’s always important to appreciate the limitations of observational studies, including the way it may be much harder to control for confounding variables.
In this case, the study population was also exclusively made up of health professionals and may not accurately reflect the larger population, for better or worse.1
The fact that all diets detailed in this study led to healthier aging underscores the important message that a “healthy diet” has some flexibility and can be molded to fit diverse individual needs and preferences. Every day, dietitians stand at the helm in guiding patients and clients in building evidence-based personalized nutrition plans to support reduced risk for chronic illness, improved quality of life, and healthier aging. They may encounter those in midlife who feel defeated and mistakenly believe it’s “too late” to make healthier changes that matter. In those moments, RDs can empower these patients and clients by sharing the truth: middle age still holds plenty of power to change the future.
— Heather Davis, MS, RDN, LDN, editor
References
1. Tessier AJ, Wang F, Korat AA, et al. Optimal dietary patterns for healthy aging. Nat Med. 2025;31(5):1644-1652.
2. WHO’s work on the UN Decade of Healthy Ageing (2021–2030). World Health Organization website. https://www.who.int/initiatives/decade-of-healthy-ageing. Updated 2025. Accessed July 22, 2025.
