Whether you're trying to adhere to the Mediterranean, DASH, or MIND diets, eating more ultra-processed foods can increase your risk of cognitive decline and stroke, a new study has found.
All three diets are plant-based and focus on eating lots of fruits, vegetables, whole grains, beans and seeds, while limiting sugar, red meat and ultra-processed foods.
“In this study, a 10 percent increase in intake of ultra-processed foods was associated with a 16 percent increased risk of cognitive impairment,” said Dr. Andrew Freeman, a cardiologist and director of cardiovascular prevention and health care at National Jewish Health in Denver, who was not involved in the study.
“You can always extrapolate that if you increase your intake of ultra-processed foods by 100%, your chances of developing cognitive impairment increase by 160%,” he said. “Of course, this study only shows an association, not a direct cause-and-effect relationship.”
Meanwhile, eating more unprocessed or minimally processed foods lowers your risk of cognitive impairment by 12%, a study published Wednesday in the journal Neurology shows.
Unprocessed foods include fresh fruits and vegetables, eggs, and milk. Minimally processed foods include cooking ingredients such as salt, herbs, and oil, and foods that combine cooking ingredients with unprocessed foods, such as canned or frozen vegetables.
Ultra-processed foods include prepackaged soups, sauces, frozen pizza, ready-to-eat meals, hot dogs, sausages, French fries, soda, and pleasure foods such as commercial cookies, cakes, candies, donuts, and ice cream.
These foods are typically high in calories, have added sugar and salt, and are low in fiber, all of which can contribute to cardiometabolic health problems, weight gain, obesity, type 2 diabetes, and high blood pressure. experts say.
Increased risk of stroke
The study analyzed data from 30,000 participants in the REGARD (Reasons for Geographic and Racial Disparities in Stroke) study, a nationally diverse population followed for up to 20 years.
Study author Dr. W. Taylor Kimberly, a neurologist and chief of the neurocritical care unit at Massachusetts General Hospital in Boston, said people who included the most ultra-processed foods in their diet had an 8 percent higher risk of stroke compared with those who ate the least processed foods.
For black participants, that risk rose to 15 percent, likely due to the effect of ultra-processed foods on high blood pressure in black populations, Kimberly said. But eating more unprocessed or minimally processed foods was associated with a 9 percent lower risk of stroke, the study found.
Why do ultra-processed foods undermine your efforts to maintain a healthy diet? Poor nutritional content and a tendency for blood sugar levels to spike may be to blame, Pei-Pei Gao and Zhendong Mei wrote in an editorial published with the study.
May is a medical fellow at Brigham and Women's Hospital in Boston, and Gao is a graduate student in nutrition at the Harvard T.H. Chan School of Public Health, also in Boston. Neither was involved in the study.
Type 2 diabetes, obesity, high blood pressure and high cholesterol are all major risk factors for vascular disease of the heart and brain, the researchers write.
The vascular effects that lead to stroke and cognitive decline may also be due to “the presence of additives such as emulsifiers, colours, sweeteners and nitrates/nitrites, which have been associated with disruption of the gut microbial ecosystem and inflammation,” the researchers said, they added.
The growing dangers of ultra-processed foods
There's a mountain of research on the dangers of eating ultra-processed foods: A February review of 45 meta-analyses involving nearly 10 million people found that eating 10 percent more ultra-processed foods increased the risk of developing or dying from dozens of adverse health conditions.
This 10% increase is considered a “baseline” and adding more ultra-processed foods could increase the risk, experts say.
The review said there was strong evidence that high intakes of ultra-processed foods increase the risk of cardiovascular disease-related death and common mental disorders by about 50 percent.
Researchers also found that eating more ultra-processed foods increased the risk of obesity by 55 percent, the risk of sleep disorders by 41 percent, the risk of developing type 2 diabetes by 40 percent, and the risk of depression by 20 percent. We also found some very suggestive evidence.
“We really need to put a 'Warning, this food may be harmful to your health' label in the ultra-processed food aisle and on the packaging like we do with cigarettes,” Freeman said.
“What we think of as 'convenience foods' really needs to change from packets of crisps to apples and carrots that are shelf-stable and can be carried in handbags or backpacks,” he says. “And we need to make things like that more readily available, especially for our children and in food deserts where all the food available is often ultra-processed.”
