Anti-Inflammatory Diet Linked to Lower Dementia Risk

When you get injured or are sick, certain cells and hormones in your body go to work on healing. This is done by creating an inflammatory response called acute inflammation, a necessary step in recovering from illness and healing a wound or injury. An example of this is when you sprain your ankle and it swells up—although in other circumstances the inflammation is not as obvious as this and we often don’t see it. As healing occurs, the inflammation gradually dissipates. 

But there’s another type of inflammation—chronic inflammation—that tends to stick around and hang out in your body like an irritating roommate you can’t get rid of. This type of inflammation can be damaging to your body and has been connected to many chronic conditions, including heart disease, type 2 diabetes and stroke (to name a few). 

These particular conditions—heart disease, stroke and type 2 diabetes, which are considered cardiometabolic diseases—have, in turn, been linked to an increased risk of dementia. This also means that chronic inflammation is linked to dementia.

Diet can play a big role in fanning the flames of inflammation, too. For example, what researchers consider a typical Western diet pattern, characterized by a high intake of red meat, high-fat dairy products, refined grains and highly-processed foods, has been associated with higher inflammatory markers in the body. On the other hand, eating patterns characterized by higher amounts of fruits, vegetables, whole grains, fish and legumes, like the Mediterranean diet, tend to be associated with lower inflammatory markers.

While researchers understand there is a connection between inflammation, cardiometabolic diseases and dementia, and evidence suggests there’s a link between inflammatory foods and increased inflammation in the body, they still have unanswered questions. Like, if people with cardiometabolic diseases follow an anti-inflammatory eating pattern, could they reduce their risk of dementia despite having pre-existing risk factors for dementia? 

This is the question researchers set out to answer in a new study published on August 12, 2024 in JAMA Network Open. Let’s dive in. 

How Was This Study Conducted & What Did They Find?

Participants for this study were part of the UK Biobank, an ongoing long-term study that includes adults between the ages of 40 and 70 from across the UK. This study included 84,342 people from the Biobank with an average age of 64, about half of them female. 

Other demographic information that was collected included race and ethnicity, height and weight, blood pressure, smoking status and physical activity. Researchers also looked at participants’ bloodwork for the presence or absence of a gene that indicates a genetic predisposition to Alzheimer’s disease.

Diet information was gathered via 24-hour dietary assessments administered at baseline (the beginning of the study) and up to four additional times over 18 months. The assessments measured the intake of 206 foods and 32 drinks. Energy and nutrient intake were calculated based on these assessments, as were dietary inflammatory index (DII) scores. The DII has been validated in previous research and assigns an inflammatory effect score to foods, based on what is currently known about that food’s inflammatory response. Anti-inflammatory foods receive a negative number, while foods that tend to be proinflammatory receive a positive number. This is one assessment where a lower number is more favorable.

A subset of 8,917 participants who were free of neurological diseases at the time also underwent a brain MRI so researchers could detect changes in the brain during the study period. This is important since dementia is brain-related.

After all the data was collected and numerous statistical analyses were run, including after adjusting for confounding variables (like demographics), the results were in. 

Dementia risk was 31% lower in people with cardiometabolic diseases who ate an anti-inflammatory diet compared to those with cardiometabolic diseases who ate a proinflammatory diet. 

And that’s not all. Remember the brain MRIs? The participants who followed an anti-inflammatory eating pattern also had significantly larger grey matter volume in their brains—indicating less neurodegeneration—and significantly smaller white matter hyperintensities—indicating less vascular injury. 

Researchers state that these brain findings fall within the framework of inflammaging, a theory that aging and disease development in older people are due to breakdowns in the normal balance of proinflammatory and anti-inflammatory processes as we age. In other words, aging boils down to inflammation and the presence or absence of it.

How Does This Apply to Real Life?

One of the conclusions these researchers note that their results highlight is that diet matters and is a modifiable factor in disease prevention. This means that modifiable behaviors, like choosing what you eat, can influence disease risk even despite having pre-existing conditions—like heart disease, diabetes and stroke—that put you at higher risk of other conditions (in this case, dementia).

While aging is unavoidable, the rate at which you age may be at least in part within your control. In our Healthy Aging Diet Center, you’ll find an array of articles on healthy aging and brain health. For example, we’ve got recipes and information on the MIND diet, an eating pattern that combines elements of the Mediterranean diet and the DASH diet, the latter of which is a diet for hypertension to help prevent or slow neurodegenerative delay. 

We’ve also reported on how sitting too much can speed up aging, how sleep affects aging and what types of exercise may slow aging. And then there’s stress, which speeds up the aging process and can impair cognitive functions. Stress can also influence sleep and eating, which can influence exercise—and so the vicious cycle goes. 

The Bottom Line

This study suggests that for those with cardiometabolic diseases, like heart disease, type 2 diabetes and/or stroke, their risk of developing dementia decreased by 31% when eating a diet high in anti-inflammatory foods compared to people with cardiometabolic diseases who ate proinflammatory foods. This stresses the importance of managing behaviors within your control, including what you choose to eat, how often you move your body, how much quality sleep you get and what stressors you allow in your life.