With life expectancy rising among older adults, promoting healthy aging has become a global priority to help people live long, healthy and productive lives.
There’s convincing evidence from randomized controlled trials and observational studies that eating a high-quality diet guards against heart disease, stroke, type 2 diabetes and premature death.
In fact, diet is considered the leading behavioural risk factor for chronic disease risk and mortality worldwide.
Now, new research adds weight to the strong connection between diet and healthy aging.
According to the findings, following a healthy diet during midlife – in your 40s, 50s and 60s – greatly increases the odds of becoming a healthy ager.
Here’s what we know about the study, plus the best dietary patterns to help you stay healthy and vital to the age of 70 and beyond.
The latest research
The study, published March 24 in the journal Nature Medicine, evaluated the relationship between long-term adherence to healthy dietary patterns during midlife and healthy aging.
To do so, researchers from the Harvard T.H. Chan School of Public Health, the University of Montreal and the University of Copenhagen analyzed data from 105,015 U.S. middle-aged adults who were followed for up to 30 years.
Healthy aging was defined as living to the age of 70 years free of 11 major chronic diseases – such as hypertension, heart disease, cancer and diabetes – and without impairment in cognitive function, physical function or mental health. (According to the Public Health Agency of Canada, 73 per cent of Canadians over 65 have at least one chronic disease.)
Participants who did not meet this criteria were considered usual agers.
Every two years, participants completed questionnaires about their health and lifestyle habits. Dietary information, collected every four years, was used to assess how closely participants’ diets matched eight dietary patterns.
These included the Alternative Healthy Eating Index, the Alternative Mediterranean Index, the Dietary Approaches to Stop Hypertension (DASH), the Mediterranean-DASH Diet Intervention for Neurodegenerative Delay (MIND), the Healthful Plant-based Diet, the Planetary Health Diet Index, the empirically inflammatory dietary pattern and the empirical dietary index for hyperinsulinemia (high blood levels of insulin).
The researchers also calculated participants’ intake of ultra-processed foods.
Diets plentiful in plant foods promote healthy aging
After 30 years of follow up, 9,771 (9.3 per cent) participants achieved healthy aging.
Higher adherence to any of the eight dietary patterns was associated with greater odds of healthy aging.
All dietary patterns prioritize fruits, vegetables, whole grains, unsaturated fats, nuts and pulses (e.g., beans, chickpeas, lentils) and limit red and processed meats, added sugars and sodium.
The Alternate Healthy Eating Index (AHEI) showed the strongest protective effect. Participants with the highest adherence to this pattern were 86 per cent more likely to be a healthy ager compared to those who didn’t follow the pattern closely.
When the age threshold for healthy aging was increased to 75, the AHEI again showed the strongest protection; those who followed the dietary pattern closely were 2.24 times more likely to achieve healthy aging.
Of the eight dietary patterns, the healthful plant-based diet had the weakest association with healthy aging.
These findings were independent of other lifestyle factors including physical activity level, smoking and body mass index.
Participants who consumed the most ultra-processed foods (versus the least) were 32 per cent less likely to be a healthy ager.
Higher consumption of ultra-processed foods was also tied to lower odds of each healthy aging component – maintaining intact cognitive function, intact physical function and intact mental health, as well as reaching age 70 free of chronic disease.
The study was observational, so it doesn’t prove that eating these diets resulted in healthy aging among participants. Still, the findings line up with those from other studies examining healthy dietary patterns.
What is the Alternate Healthy Eating Index?
The AHEI, developed by Harvard University researchers, scores diet quality based on how often a person consumes 11 foods and nutrients predictive of chronic disease. The highest possible AHEI score is 110; higher scores indicate better diet quality.
For each dietary component, a score ranging from 0 (non-adherence) to 10 (perfect adherence) is given.
For example, if your daily diet includes at least four servings of whole fruit, you would earn 10 points. If you don’t eat any fruit, you would score 0 points.
You’ll also get 10 points for each of the following: eating three ounces of oily fish each week and at least 2.5 cups of vegetables, one ounce of nuts, six servings of whole grains and healthy fats every day.
Other components scored by the AHEI include sugar-sweetened drinks, red and processed meats, sodium and alcoholic beverages.
Bottom line
The new study findings suggest that there are multiple ways to eat to support healthy aging.
Whether you prefer to model your diet after the Mediterranean, DASH, the AHEI or another healthy dietary pattern, the key is ramping up your intake of a variety of whole plant foods.
Leslie Beck, a Toronto-based private practice dietitian, is the clinical director of food and nutrition at Medcan. Follow her on X @LeslieBeckRD
