Our cognitive health on our plate... and in our microbiota!

Vegetables, fruits, nuts, olive oil, fish... the Mediterranean diet, known for its many benefits, could have one more advantage: slowing cognitive decline.
That is what a study ¹ of 54 Chinese seniors with or without mild cognitive impairment (sidenote: Mild Cognitive Impairment (MCI) MCI is a clinical stage between the expected cognitive decline of normal aging and the more severe decline of dementia. Individuals with MCI have noticeable memory or thinking problems but can still perform most daily activities, representing a critical window for intervention and study. ) suggests. The study explored the effect of anti-inflammatory diets (sidenote: Anti-inflammatory diets Diets characterized by high consumption of fruits, vegetables, whole grains, legumes, fatty fish, nuts, olive oil and phytochemicals, while limiting the intake of foods with potentially pro-inflammatory properties such as red meat, refined carbohydrates and alcohol. The rationale for anti-inflammatory diets (including but not limited to the Mediterranean diet) lies in their capacity to decrease inflammation.

Source: Yu X, Pu H, Voss M. Overview of anti-inflammatory diets and their promising effects on non-communicable diseases. Br J Nutr. 2024 Oct 14;132(7):898-918. doi: 10.1017/S0007114524001405.  ) , in particular the Mediterranean diet.

When your plate calms inflammation and boosts cognition

The researchers observed that people who follow an anti-inflammatory diet have a more diverse population of oral bacteria, including a higher number of certain “good bacteria” such as Corynebacterium or Eubacterium yurii.
In return for the shelter and food we provide, these bacteria offer major benefits: they produce butyrate, for example, a compound that calms inflammation, protects the brain and supports memory. The same applies to the gut: the microbiota of people consuming anti-inflammatory diets hosts specific bacteria. 
Result of this mouth–gut–brain interconnection: higher cognitive scores on memory, attention and language tests among people who follow anti-inflammatory diets!

When your plate sparks inflammation, your brain takes the hit

In contrast, fans of diets high in saturated fat and low in fruits and vegetables (in short, pro-inflammatory diets) showed a decrease in oral bacterial diversity.

Less friendly bacteria such as Lacticaseibacillus took over. The problem: some of them are known to produce acids that cause cavities and trigger systemic inflammation, a factor linked to cognitive decline.
The same goes for gut microbiota: inflammatory diets promote bacteria associated with lower cognitive performance and weaken the microorganisms that could have boosted it.

Result: unimpressive cognitive scores for lovers of junk food!