A study by scientists at Rush University Medical Center found that adding more food to the Western diet could reduce the cognitive benefits of the Mediterranean diet.
A healthy diet, such as the Mediterranean diet, has positive effects on health, but little is known about the effects of incorporating unhealthy foods into a healthy diet. Researchers at Rush University Medical Center reported reduced benefits of the Mediterranean diet among those who frequently ate unhealthy foods. The results of their study were published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.
“A diet that focuses on vegetables, fruits, fish and whole grains can have a positive impact on human health,” said Pooja Agarwal, an epidemiologist and assistant professor of internal medicine at Rush University Medical Center. “But when combined with fried, sweet, refined cereals, red meats and processed meats, the benefits of following the Mediterranean portion of the diet seem to diminish.”
The Mediterranean diet is associated with slower rates of cognitive decline in the elderly.
One observational study included 5,001 seniors living in Chicago. All participated in the Chicago Health and Aging Project, a cognitive health assessment of adults over the age of 65, conducted from 1993 to 2012. Every three years, study participants completed a questionnaire examining basic information processing skills and memory. and completed a questionnaire on the frequency with which they consumed 144 foods.
The researchers analyzed how closely each of the study participants followed the Mediterranean diet, which includes daily consumption of fruits, vegetables, legumes, olive oil, fish, potatoes and whole grains, as well as moderate consumption of wine. They also assessed how much each participant ate a western diet, which included fried foods, processed cereals, sweets, red and processed meats, full-fat dairy products and pizza. They gave each food a score from zero to five to arrive at an overall Mediterranean diet score for each participant, ranging from zero to 55.
The researchers then looked at the relationship between Mediterranean diet scores and changes in participants’ global cognitive function, episodic memory and perceptual speed. The participants with the slowest cognitive impairment during many years of follow-up were those who ate the most Mediterranean diet, along with limiting the foods that are part of the western diet, while the participants who ate more than the western diet did not have the beneficial effects of the ingredients. healthy foods, to slow down cognitive impairment.
There was no significant correlation between age, gender, race or education with cognitive impairment in either high or low levels of Western diets. The study also included models for smoking status, body mass index and other possible variables, such as cardiovascular disease, and the results remained the same.
“Western diets can be detrimental to cognitive health,” said Agarwal. “People who scored high on the Mediterranean diet, compared to those who scored the lowest, were mentally equivalent to 5.8 years younger.”
Agarwal said the results complement other studies showing that the Mediterranean diet reduces the risk of heart disease, certain cancers and diabetes, and confirms previous research on the Mediterranean diet and brain function. The study also notes that most of the nutritional models that have been shown to improve cognitive function in older adults, including the Mediterranean diet, the MIND diet and the DASH diet, have a unique scoreboard based on the number of servings consumed. for each component of the diet.
“The more we can include green leafy vegetables, other vegetables, berries, olive oil and fish in our diet, the better for our aging brain and body. Other studies show that red and processed meats, fried foods and low intake of whole grains are associated with more inflammation and faster cognitive decline in old age, Agarwal said. “In order to benefit from diets such as the Mediterranean diet or the MIND diet, we must limit our intake of processed foods and other unhealthy foods, such as fried foods and sweets.”
The study and its results can not be easily generalized. Future long-term nutrition and cognitive function studies in the middle-aged population are needed to extend these results.