A large new study suggests that changing to a healthier diet in middle age could lower your risk of dementia—even if you haven’t eaten well before.
The research, presented at the American Society for Nutrition’s annual meeting, found that people who improved their diet during mid to late life were 25% less likely to develop Alzheimer’s disease or other forms of dementia later on.
The study was led by Dr. Song-Yi Park, an associate professor at the University of Hawaii at Manoa. She and her team wanted to know whether adopting better eating habits later in life could still help prevent memory problems and brain decline. The results offer a hopeful message: it’s never too late to start eating right.
To conduct the research, the team analyzed data from nearly 93,000 adults who were part of a long-term health study that began in the 1990s. At the start, participants were between 45 and 75 years old. Over time, more than 21,000 of them were diagnosed with Alzheimer’s disease or other forms of dementia.
The researchers looked at the participants’ diets over a 10-year period, based on food questionnaires. They focused on how closely people followed the MIND diet.
This diet is a blend of two well-known healthy eating patterns: the Mediterranean diet and the DASH diet (which stands for Dietary Approaches to Stop Hypertension). Together, they form a way of eating that supports brain health.
The MIND diet recommends foods like whole grains, green leafy vegetables, berries, nuts, beans, fish, and poultry. It also encourages people to eat less red meat, cheese, sweets, butter, and fried or fast foods. It’s based on research showing that certain nutrients help reduce inflammation and protect brain cells.
Among the study group, people who followed the MIND diet from the beginning had a 9% lower risk of dementia overall. The benefits were even stronger among certain groups—Black, Hispanic, and white participants saw a 13% reduction in risk.
But the most striking finding was this: those who improved their diet over the years, even if they didn’t start out eating well, had the biggest reduction in dementia risk—25% lower compared to those whose diets got worse.
Dr. Park explained that the positive effects of a healthy diet were clearer in some populations than others. For example, the benefits were more obvious in Black, Latino, and white participants, but were less noticeable among Asian Americans and Native Hawaiians.
This may be because different groups have different traditional diets and health patterns. Dr. Park suggested that future studies should look more closely at how diet works in different communities.
The study hasn’t yet been published in a scientific journal, so the results are considered preliminary. But they fit with what scientists already know about nutrition and brain health. Over time, a diet rich in vegetables, fiber, and healthy fats—and low in processed foods—can help protect against diseases that damage the brain, such as stroke, diabetes, and high blood pressure.
This study adds to growing evidence that what we eat has a major impact on brain health—and that it’s never too late to make a difference. Even people who didn’t follow a healthy diet early in life could benefit by changing their habits in their 40s, 50s, or 60s.
The 25% reduction in dementia risk among those who improved their diet is significant. It means that one in four cases might be preventable just by eating better. This could lead to fewer people suffering from memory loss, fewer families caring for loved ones with dementia, and reduced healthcare costs.
The study also highlights the importance of tailoring dietary advice to different cultural and ethnic groups. While the MIND diet showed benefits for many, it didn’t work equally for all. That suggests more personalized guidance could help improve brain health in more communities.
In the end, the takeaway is simple but powerful: small changes to what you eat—even later in life—can protect your brain and possibly delay or prevent dementia. You don’t have to be perfect. Just adding more berries, vegetables, nuts, and fish, and cutting back on fried food and sweets, could give your brain the support it needs to stay healthier for longer.
If you care about nutrition, please read studies about the harm of vitamin D deficiency you need to know, and does eating potatoes increase your blood pressure?
For more information about health, please see recent studies about unhealthy habits that may increase high blood pressure risk, and results showing MIND diet may reduce risk of vision loss disease.
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