Can an Anti-Inflammatory Diet Protect Your Brain? A New Study Says Yes

People with heart disease or type 2 diabetes who eat an anti-inflammatory diet may be less likely to develop dementia than people who eat a pro-inflammatory diet, new research has found.

An anti-inflammatory diet is high in foods like berries, green leafy vegetables, extra-virgin olive oil, whole grains, and fish, as well as spices like garlic, ginger, and turmeric. A pro-inflammatory diet goes heavy on highly processed foods, refined grains, red meat, and whole-fat dairy.

The findings add insight into the relationship between diet and dementia in people with cardiometabolic disease, which is a major dementia risk factor, says the lead study author, Abigail Dove , a PhD student at the Aging Research Center at Karolinska Institutet in Stockholm.

Type 2 diabetes, heart disease, and stroke are all part of a group of conditions known as cardiometabolic diseases. There's evidence that people with at least two cardiometabolic diseases have double the risk of dementia.

Can Diet Change Inflammation Levels in the Brain?

Previous studies have found a link between higher levels of inflammation throughout the body and dementia risk.

Population studies have also shown that for healthy people, an anti-inflammatory diet, the Mediterranean diet , or the MIND diet are all associated with lower risk of dementia.

For the new study, researchers set out to discover if a healthy low-inflammatory diet could impact dementia risk in people who already had heart disease , stroke , or type 2 diabetes .

Using data from the UK Biobank, the observational study followed more than 84,000 dementia-free adults age 60 and older, with a median follow-up of 12.4 years.

"Observational" means that the researchers analyzed certain outcomes by simply following what people were already doing in their daily life. People in the study weren't told to eat a certain way or focus on specific foods.

About 8,000 of those participants also underwent a brain BMI (brain–machine interface) examination, which allowed investigators to look at markers that indicate dementia.

At baseline and up to four additional times during the follow-up, participants completed a questionnaire asking about what foods and how much of those foods they consumed over the past 24 hours, says Dove.

That information was plugged into the Dietary Inflammatory Index, a well-known validated tool, to calculate an average overall score based on how those foods are known to impact inflammation throughout the body.

Participants were placed into three equal-size groups: those with the lowest scores were categorized as having an anti-inflammatory diet; those with the highest scores were categorized as having a pro-inflammatory diet; and those in the middle were categorized as having a neutral diet.

Dementia was diagnosed on the basis of an algorithm using information from patient medical records, self-reported medical history, and death registers, which has been shown to predict dementia in about 4 out 5 cases.

In order to zero in on the impact of diet, researchers then controlled for many factors that have been linked with cognitive decline, including educational level, income, race, overweight and obesity, high blood pressure, smoking, and physical activity.

People Who Ate an Anti-Inflammatory Diet Had a 31 Percent Lower Risk of Dementia

The participants with cardiometabolic disease who followed an anti-inflammatory diet were 31 percent less likely to develop dementia than those who consumed a proinflammatory diet.

Another way to understand the reduced risk is that people eating the anti-inflammatory diet developed dementia about two years later than people eating the proinflammatory foods, says Dove.

While there have been many studies suggesting it is important to eat healthy foods to help prevent Alzheimer's disease and maintain brain health, the exact biological reasons haven't been fully understood, says Yian Gu, MD, PhD , an associate professor of neurological sciences at the Columbia University Medical Center in New York City.

"The study not only provides additional evidence to support eating healthy foods, but also explains why such a diet is good, which is through anti-inflammation," says Dr. Gu, who wasn't involved in the new study.

Brain MRIs Suggest That a Diet Lower in Inflammation May Protect the Brain

Brain MRI scans of the anti-inflammatory diet group showed significantly larger gray matter volumes and fewer "white matter hyperintensities," which are small lesions and microbleeds that are associated with several risk factors for dementia.

Chronic low-grade inflammation is a key feature of cardiometabolic diseases and has been implicated in the development of dementia, says Dove. The authors suspect that lowering inflammation throughout the body via anti-inflammatory foods could slow the progression of neurodegenerative damage and vascular injury in the brain and lower the risk of cognitive impairment and eventually dementia.

Vascular injury can happen when brain blood vessels are damaged or blood flow to the brain is impaired, which means the brain doesn't get the optimal amount of oxygen. Vascular dementia is the second most common type of dementia after Alzheimer's disease.

Diet Might Have a Real Impact on Dementia Risk - but More Research Is Needed

Overall, the study is important because it suggests that for people in this higher risk group, changing what they eat could be an effective strategy for lowering their chances of developing dementia, says Dove.

But it's important to note that this was an observational study. Although the researchers found an association between an anti-inflammatory diet and reduced systemic inflammation, more favorable brain MRI markers, and lower risk of dementia, the study does not prove that diet caused those positive changes.

"Interventional studies in which participants are randomized to an anti-inflammatory versus pro-inflammatory diet would be required to conclusively test this hypothesis," says Dove.

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Sources

1. Dove A et al. Anti-Inflammatory Diet and Dementia in Older Adults With Cardiometabolic Diseases. JAMA Network Open . August 12, 2024.
2. Dove A et al. Cardiometabolic Multimorbidity Accelerates Cognitive Decline and Dementia Progression. Alzheimer's & Dementia: The Journal of the Alzheimer's Association . June 16, 2022.
3. Mekli K et al. Association Between an Inflammatory Biomarker Score and Future Dementia Diagnosis in the Population-Based UK Biobank Cohort of 500,000 People. PLoS One . July 19, 2023.
4. What Do We Know About Diet and Prevention of Alzheimer's Disease? National Institute on Aging . November 20, 2023.
5. Vascular Dementia: Causes, Symptoms, and Treatments. National Institute on Aging . November 1, 2021.

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Becky Upham

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Becky Upham has been professionally involved in health and wellness for almost 20 years. She's been a race director, a recruiter for Team in Training for the Leukemia & Lymphoma Society, a salesperson for a major pharmaceutical company, a blogger for Moogfest, a communications manager for Mission Health, a fitness instructor, and a health coach.

She majored in English at the University of North Carolina and has a master's in English writing from Hollins University.

Upham enjoys teaching cycling classes, running, reading fiction, and making playlists.

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