April 24, 2025, 12:15 pm | Read time: 5 minutes
This question is certainly on the minds of many health-conscious people: What is the best way to eat to stay as healthy as possible into old age? A large-scale study now shows which dietary patterns are associated with healthy ageing.
Anyone with an interest in health will probably know that drinking alcohol and smoking cigarettes have a particularly negative impact on our health. For example, both alcohol and cigarettes are associated with an increased risk of various types of cancer as well as cardiovascular and metabolic diseases. Combined consumption in particular increases the health risks enormously, as the German Cancer Research Center warns.1 So if you want to grow old healthily, it’s best to avoid both. But what about our eating habits? What influence does diet have on healthy aging? This question has now been answered by a recent study conducted by researchers from the Harvard T.H. Chan School of Public Health in collaboration with scientists from the University of Copenhagen and the University of Montreal.
Overview
Researchers Investigated Holistic Dietary Patterns
It is difficult to say how a single food affects our health. This is because it is usually just one piece of the puzzle in a holistic diet. This is why researchers are increasingly investigating so-called dietary patterns and holistic diets and how they affect our health over the years. For example, many nutrition experts such as Prof. Dr. Nicolai Worm repeatedly recommend the Mediterranean diet, a form of nutrition that is very popular in the Mediterranean region. It involves eating lots of fruit, vegetables, nuts, olive oil, and oily sea fish. And this has a positive effect on health. Researchers from the USA, Canada and Denmark have now analyzed the health data of over 100,000 people.2 They tracked their dietary patterns and disease progression over a period of 30 years.
How the Study Worked
Data from the American “Nurses’ Health Study” and the “Health Professionals Follow-Up Study” were used for the study. These included around 105,000 women and men working in the healthcare sector. The subjects were between 39 and 69 years old, 66 percent of whom were women. The average age was 53. Over a period of 30 years, the study participants regularly completed questionnaires about their diet. These were then analyzed by the researchers. Eight healthy dietary patterns served as a reference, including the Mediterranean diet. All healthy dietary patterns emphasized a high consumption of the following foods:
- Fruit and vegetables
- Whole grain products
- Unsaturated fats (from plant sources)
- Nuts and pulses
- Some of the diets also promoted a moderate intake of healthy animal foods such as fish and certain dairy products.
In comparison to healthy eating habits, the researchers also evaluated unhealthy eating habits and looked at their influence on health. For example, the intake of highly processed foods (e.g. ready meals) with artificial ingredients, lots of sugar, salt, and unhealthy fats is considered unhealthy.
What Does Healthy Aging Mean?
But what does healthy aging actually mean? Here, too, the researchers have come up with a definition. They define healthy aging as reaching the age of 70 without serious chronic diseases and with good cognitive, physical, and mental health. Factors such as body mass index (BMI), smoking behavior, and physical activity were also taken into account.
This Diet Can Promote Healthy Aging
The evaluation of the study showed that 9771 of the 105,000 participants aged healthily. The percentage was therefore 9.3 percent. As the researchers found out, the positive dietary patterns were associated with healthy aging overall. This included positive effects on the cognitive, physical and mental health of the test subjects.
The effect was particularly positive in subjects who followed the recommendations of the AHEI diet. The abbreviation AHEI stands for ‘Alternative Healthy Eating Index.’ The AHEI diet, which scores highly on this index, includes lots of vegetables, fruit, pulses and nuts. Meat, fish and dairy products are only allowed in moderation. Sweetened drinks, red and processed meat, lots of salt and trans fats should be avoided. The AHEI diet was developed to prevent chronic diseases.
In fact, study participants who scored particularly well on the Alternative Healthy Eating Index were 86 percent more likely to be healthy at the age of 70. They were also more than twice as likely to remain healthy at age 75 compared to participants who scored poorly on the AHEI diet. Overall, the data analysis showed that a primarily plant-based, nutrient-rich diet with moderate consumption of healthy animal foods and low-fat dairy products appeared to be most clearly associated with healthy aging.
In contrast, the researchers found that higher consumption of highly processed foods, particularly meat products and sugary and diet drinks, was negatively associated with healthy aging.
Researchers Recommend Eating Lots of Plant-Based Foods
“Our findings suggest that a diet high in plant-based foods and moderate in healthy animal-based foods may promote healthy aging overall and help shape future dietary guidelines,” explains study co-author Marta Guasch-Ferré in a press release from the Harvard T.H. Chan School of Public Health.3
However, the study results also showed that there is no one-size-fits-all diet, adds lead author Anne-Julie Tessier. “Healthy eating can be adapted to individual needs and preferences,” she says. So you don’t always have to adhere consistently and strictly to a healthy diet. The important thing is to try to eat healthily about 80 percent of the time. A piece of cake or another “dietary sin” that you occasionally indulge in is not so significant.
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Limitations of the Study
However, the researchers themselves also point out that this study has some limitations. This is primarily because the data was based solely on test subjects who work in the healthcare sector. This could mean, for example, that they generally had a somewhat healthier diet than the average population. It is therefore important to carry out this study in other population groups with different socio-economic status and cultural backgrounds. This is the only way to generalize the findings of this study.