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Eating unhealthy foods can reduce the benefits of otherwise healthy diets, study finds

Experts say eating more processed foods can affect cognitive function into old age

Photo (c) mediaphotos - Getty Images
Following a healthy diet can have lasting benefits for consumers’ physical and mental health. But researchers from Rush University Medical Center are exploring the effects of straying from a traditionally healthy diet with some unhealthy food choices. 

Their study focused on the Mediterranean diet, which encourages consumers to eat lots of fruits, vegetables, and healthy fats and has been linked with several health benefits. The researchers learned that properly following the Mediterranean diet can have long-term physical and cognitive benefits for consumers -- especially as they enter into older age; however, regularly incorporating processed foods, fried foods, or other unhealthy options can eliminate the benefits of following the diet. 

“Eating a diet that emphasizes vegetables, fruit, fish, and whole grains may positively affect a person’s health,” said researcher Puja Agarwal, Ph.D. “But when it is combined with fried foods, sweets, refined grains, red meat, and processed meat, we observed that the benefits of eating the Mediterranean part of the diet seems to be diminished.” 

Unhealthy foods can affect the aging process

To see how unhealthy foods can affect otherwise healthy diets, the researchers followed 5,001 participants over the age of 65 enrolled in the Chicago Health and Aging Project over the course of nearly 20 years.

The researchers checked to see how frequently the participants consumed specific foods that lined up with the Mediterranean diet and a more Western diet, which includes fried foods, full-fat dairy products, and sweets, among other things. The participants’ cognitive abilities were also evaluated using several different memory and functioning tests. 

Each participant was given a score based on how closely their diets aligned with the Mediterranean diet or how far they strayed from the healthier options. The researchers then compared those scores with how well the participants fared on the cognitive assessments. 

The researchers learned that eating more unhealthy foods was linked with poorer cognitive function -- even when accompanied with healthy items. They also found that eating larger quantities of processed foods, refined grains, and fried foods can negatively affect the cognitive aging process while eliminating the health benefits of consuming healthier options. 

“Individuals who had a high Mediterranean diet score compared to those who had the lowest score were equivalent to being 5.8 years younger in age cognitively,” said Dr. Agarwal. 

Moving forward, the researchers hope that consumers make healthier choices as often as possible so that they can enjoy long-lasting physical and cognitive health benefits.

“The more we incorporate leafy green vegetables, other vegetables, berries, olive oil, and fish into our diets, the better it is for our aging brains and bodies,” Dr. Agarwal said. “Other studies show that red and processed meat, fried food, and low whole grains intake are associated with higher inflammation and faster cognitive decline in older ages. To benefit from diets such as the Mediterranean diet, or MIND diet, we would have to limit our consumption of processed foods and other unhealthy foods such as fried foods and sweets.” 

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