Eating a diet that suppresses ongoing, low-grade inflammation in the body has been linked to numerous health advantages, including protection against heart disease, stroke, certain cancers and depression.
This eating pattern is also associated with slowing cognitive decline and reducing the risk of dementia in older adults.
What’s unclear, however, is whether an anti-inflammatory diet can support brain and cognitive health in older adults who already have a major dementia risk factor, specifically coronary heart disease, stroke or type 2 diabetes.
According to a new large-scale study, eating more anti-inflammatory foods offers brain protection even among people living with a chronic cardiometabolic disease.
The cardiometabolic-brain link
Previous studies have associated cardiometabolic diseases such as type 2 diabetes, heart disease and stroke with an increased risk of dementia, especially when they occur together.
It’s estimated that one-third of all Alzheimer’s dementias, for example, are caused by risk factors for cardiovascular disease, such as high blood pressure and elevated LDL blood cholesterol.
Both risk factors are tied to inflammation and oxidative stress, which can increase the build-up and/or inhibit the removal of beta-amyloid plaques in the brain, the hallmark sign of Alzheimer’s disease.
The metabolic dysfunction that occurs with insulin resistance or type 2 diabetes is thought to inflame brain cells, damage blood vessels in the brain and impair the ability of insulin to perform its normal brain functions, which include memory and learning.
What is an anti-inflammatory diet?
An anti-inflammatory diet combines a variety of whole, largely plant-based, foods which provide vitamins, minerals, fibre, healthy fats, antioxidants and phytochemicals, all of which work together to prevent or dampen inflammation.
At the same time, an anti-inflammatory diet limits refined grains, added sugars, red and processed meats and unhealthy fats, diet components that can cause or worsen inflammation.
The Mediterranean diet, the MIND diet, the DASH diet, the Nordic diet and healthy vegetarian diets are examples of anti-inflammatory eating patterns.
The latest research
The new study, published August 12 in the journal JAMA Network Open, analyzed the diets of 84,342 older adults, average age 64, participating in the UK Biobank, an ongoing study of more than 500,000 adults across the United Kingdom.
Dietary information was collected at the start of the study and at four additional times throughout.
The researchers used a validated tool called the Dietary Inflammatory Index (DII) to score the inflammatory potential of participants’ diets. Participants were categorized as having an anti-inflammatory diet, a neutral diet or a pro-inflammatory diet based on their scores.
Nearly 9,000 participants also underwent MRI brain scans during the study.
Anti-inflammatory diet delays dementia onset
A total of 1,559 participants developed dementia over the study’s follow-up period of up to 15 years.
Overall, having type 2 diabetes, heart disease and/or stroke was associated with an 81-per-cent increased risk of developing dementia.
Participants who followed an anti-inflammatory diet, though, had a 21-per-cent reduced risk of dementia compared to those who ate a pro-inflammatory diet.
When the researchers looked at participants with cardiometabolic diseases specifically, they found that the risk of dementia was 31-per-cent lower in those with an anti-inflammatory diet compared to a pro-inflammatory diet.
People living with type 2 diabetes, heart disease and/or stroke who followed an anti-inflammatory diet developed dementia two years later than those with a pro-inflammatory diet.
To arrive at these conclusions, the researchers controlled for other dementia risk factors, including educational level, socioeconomic status, hypertension, body mass index, smoking status and physical activity.
Brain MRI scans also revealed that participants with an anti-inflammatory diet had significantly higher grey matter volume (indicating less degeneration of brain cells) and significantly lower white matter hyperintensity volume (indicating less damage to blood vessels in the brain).
This study was observational and does not prove that eating an anti-inflammatory diet resulted in a lower dementia risk or more favourable brain MRIs.
Still, the findings add to growing evidence that eating a healthy diet protects the brain by combatting inflammation.
Shifting to an anti-inflammatory diet
Make colourful fruits and vegetables the focus of every meal.
Replace refined grains with whole grains such as brown rice, quinoa, farro, oats, 100 per cent whole grain bread and whole grain pasta.
Add beans, chickpeas and lentils to your menu. Serve a bean salad or spiced chickpeas as a side dish, toss black beans into green salads or try a lentil pasta.
Include oily fish such as salmon, trout or sardines in your weekly diet for anti-inflammatory omega-3 fats.
Cook mainly with unsaturated oils such as olive oil, avocado oil and grapeseed oil.
Flavour meals with herbs and spices, which provide anti-inflammatory polyphenols. Add nuts and seeds to meals and snacks.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD