Eating an anti-inflammatory diet of whole grains, fruits and vegetables instead of an inflammatory diet focused on red and processed meats and ultraprocessed foods, such as sugary cereals, sodas, fries and ice cream, lowered the risk of dementia by 31%, a new study found.

That benefit held true even for people with existing diagnoses of cardiometabolic conditions such as type 2 diabetes, heart disease or stroke, said Abigail Dove, lead author of the study published Monday in the journal JAMA Network Open.

“Following an anti-inflammatory diet was related to lower risk of dementia, even among people with cardiometabolic diseases who are already at elevated risk of dementia,” said Dove, a doctoral student at the Aging Research Center at Karolinska Institutet in Solna, Sweden, in an email.

In fact, people living with type 2 diabetes, stroke or heart disease who ate the most anti-inflammatory foods “developed dementia 2 years later than those with cardiometabolic diseases and a pro-inflammatory diet,” she added.

Brain scans of those who followed an anti-inflammatory diet also showed significantly lower levels of brain biomarkers of neurodegeneration and vascular injury, Dove said.

Even though the study is observational and cannot show cause and effect, the findings reflect existing research that shows a link between dietary inflammation and brain health, said Dr. David Katz, a specialist in preventive and lifestyle medicine who was not involved in the study, via email.

“It is highly likely that a higher quality, less inflammatory diet directly impacts multiple pathways related to brain and neurocognitive health over time,” said Katz, the founder of the nonprofit True Health Initiative, a global coalition of experts dedicated to evidence-based lifestyle medicine.

What is an anti-inflammatory diet?

The exact biological ways foods impact inflammatory pathways is not yet fully understood. However, researchers believe the reliance on sugary, ultraprocessed foods and the abundance of saturated fats from red and processed meats that is common in the Western diet  — along with pollution, cigarette smoke, radiation, plastics and pesticides — may lead to the increased activation of free radicals in the body.

Free radicals are molecules with unpaired electrons. Driven to search for a match, they rob other cells of their electrons, causing cellular damage that can contribute to Alzheimer’s disease and other dementias and chronic diseases.

In addition, researchers believe highly processed and fatty foods can also trigger higher levels of other inflammatory biomarkers such as C-reactive protein, interleukin 6 and tumor necrosis factor α.

A November 2020 study found people who ate higher levels of red and processed meats, such as bacon and sausage, as well as sugary, ultraprocessed foods had a 28% higher risk of stroke and a 46% higher risk of heart disease. Just a 10% increase in such foods was significantly associated with a 14% higher risk of death from all causes, according to a February 2019 study.

There is a way to fight back: Research has suggested that anti-inflammatory elements such as vitamins, carotenoids and flavonoids in foods such as fruits and vegetables may neutralize free radicals and other inflammatory markers and reduce the stress on the body, according to the Mayo Clinic.

Better brains with anti-inflammatory foods

The new study analyzed the dietary patterns of over 84,000 dementia-free adults older than age 60 with a diagnosis of type 2 diabetes and/or heart disease or stroke who were part of the UK Biobank, a longitudinal study that includes participants from England, Scotland and Wales.

Each person was asked five times about their consumption of 206 foods and 32 drinks that were divided into levels of inflammatory and anti-inflammatory nutrients. Medical records were examined over the next 15 years to discover whether there were any associations between eating the least and the most amounts of inflammatory foods and diagnoses of dementia. In addition, nearly 9,000 of the participants also underwent magnetic resonance imaging, or MRI, brain scans.

Scans found people with cardiometabolic diseases who ate the most anti-inflammatory foods had larger gray matter volume — indicating less neurodegeneration — and lower white matter intensities, which are signs of vascular injury in the brain, compared with people who ate an inflammatory diet.

While more research needs to be done, overall, “the signal is clear above the background noise,” Katz said.

“Even after one is contending with a chronic, cardiometabolic condition, the adoption of a higher quality diet appears to offer some protection to the brain, reducing and delaying both functional and anatomical signs of degradation.”