Lower dementia risk by a third with simple dietary changes

Managing inflammatory biomarkers with food may contribute to staving off dementia for up to two years and reduce the risk of developing it at all.

---

Older adults with cardiometabolic disease have 31% lower risk of dementia if they adhere to an anti-inflammatory diet, new research from the UK Biobank suggests.

An anti-inflammatory diet was also associated with an average of two years later onset than for those with a proinflammatory diet.

More than 84,000 adults aged 60 and older without dementia at baseline participated in the study, 14,000 of whom had at least one cardiometabolic disease (CMD) such as type 2 diabetes, heart disease and/or stroke. They were followed up for 12-15 years.

Of the nearly 1600 participants who developed dementia, the presence of CMDs was associated with an 81% increased risk of dementia. However, the study suggests that some of that risk can be reduced through dietary changes.

The authors note that the link between cardiometabolic disease and dementia is unclear, although it has been suspected that inflammation could be a common denominator. Dietary changes may reduce systemic inflammation and slow the development of dementia.

The cohort was assessed using the Dietary Inflammatory Index (DII) at baseline and a least four further times throughout the study period in the form of a web-based 24-hour dietary assessment. This calculated a score based on the participants’ self-reported average intake of 31 nutrients.

RMIT University lecturers in human nutrition and biosciences Dr Sharayah Carter and Dr Kaitlin Day explained to The Medical Republic that the DII rates foods based on their content of pro or anti-inflammatory nutrients.

Nutrients such as fibre, omega-3 fatty acids, antioxidants, and certain vitamins and minerals typically receive negative (anti-inflammatory) scores, while nutrients such as trans and saturated fats, and added sugars tend to receive positive (pro-inflammatory) scores.

In the cohort, DII scores ranged from −6.7 to 5.2 points. The study categorised anti-inflammatory diets as −1.5 points or less, neutral between more than −1.5 and less than 0.5 points, and proinflammatory as 0.5 points or greater.

However, Dr Day and Dr Carter say that DII scores have certain limitations such as not accounting for how food is prepared (e.g baked vs fried), how different nutrients may interact with one another, or the level of food processing, all of which influences a diet’s inflammatory potential.

“It’s important to remember that people consume whole foods, not isolated nutrients. Therefore, dietary recommendation should focus on eating a variety of whole, minimally processed foods and being mindful of how they are prepared,” they said.

What is an anti-inflammatory diet?

The study suggests that a “Western diet” as characterised by red meat, high-fat dairy, eggs, refined grains, and processed foods is associated with an increase in inflammatory biomarkers such as such as C-reactive protein, interleukin 6 and tumour necrosis factor alpha.

Lower levels of these biomarkers are associated with a diet including more vegetables, fruits, whole grains, fish, and legumes.

Drs Day and Carter say that dietary patterns such as the Mediterranean diet or the DASH diet (Dietary Approaches to Stop Hypertension) qualify as anti-inflammatory diets, which are characterised by whole, minimally processed foods rich in anti-inflammatory compounds.

These diets focus on foods which are known to reduce inflammation and oxidative stress and encourage the use of herbs and spices due to their bioactive components with significant health benefits.

What dietary changes can be made to reduce dementia risk?

Rather than focusing on food avoidance, emphasis on trying to incorporate anti-inflammatory nutrients can be an effective way to improve DII scores. Drs Carter and Day suggest these simple additions:

1. Eat the rainbow

Incorporate a wide range of colourful fruits and vegetables into the diet to ensure a variety of phytonutrients, which have anti-inflammatory effects.

2. Include healthy fats

Regularly include nuts and seeds in your diet. These provide healthy fats, fibre, and antioxidants that help reduce inflammation. Also, add fatty fish such as salmon, mackerel, and sardines to your meals for their high omega-3 content, which has strong anti-inflammatory effects. For those who do not consume fish, plant-based sources like chia seeds and walnuts are good alternatives.

3. Include fermented foods

Add fermented foods like yogurt, kefir, sauerkraut, and kimchi to support gut health by promoting a healthy balance of gut bacteria, which plays a key role in reducing inflammation.

4. Choose dark chocolate

Opt for dark chocolate over milk chocolate for its higher content of flavonoids, which have anti-inflammatory properties.

They conclude that while dietary recommendations should be tailored to individual needs, adopting an anti-inflammatory diet can complement and enhance the standard dietary advice for managing cardiometabolic diseases in patients.

“Shifting away from the traditional Western diet toward one with an emphasis on plant-based foods and healthy fats can significantly impact overall health outcomes, particularly for those at risk of dementia and CMD.”

Jama Network Open, 12 August 2024