MIND your brain

There is food for thought

Polyphenols are natural compounds found in plant-based foods. They have a significant impact on human health. They contribute to preventing cancer, cardiovascular diseases and ageing. Today, we zoom in on their neuroprotective impact.

Protect

Polyphenols help protect neurons (nerve cells) from damage, which is crucial in preventing and slowing the progression of neurodegenerative diseases like Alzheimer’s and Parkinson’s. They do this by acting as powerful antioxidants, neutralizing free radicals and reactive oxygen species that cause oxidative damage—a major factor in aging and neurodegeneration.

Polyphenols also suppress neuroinflammation. Chronic inflammation (caused by smoking, alcohol, stress, lack of exercise, bad food and other factors) is a hallmark of many neurodegenerative disorders. Since polyphenols possess strong anti-inflammatory properties, they reduce the inflammatory response that can harm brain cells. They can also shield neurons from injury induced by various neurotoxic substances. Through these mechanisms, polyphenols (as well as vitamins and other nutrients) help to prevent degeneration of the brain.

Smarter

A healthy lifestyle helps brain longevity. So far nothing new. But now it gets interesting. Several studies show that polyphenols also make you smarter. Regular intake of polyphenol-rich foods has been linked to improved cognitive function, memory, and learning. Polyphenols promote the growth and survival of neurons and enhance synaptic plasticity (the ability of synapses to strengthen or weaken over time), which is essential for learning and memory. Other studies have shown an association between polyphenol consumption and better performance in areas like language and episodic memory, and a delay in age-related cognitive decline.

Blood flow

We already knew that polyphenols have a very beneficial impact on the cardiovascular system. This extends to the brain as well. Polyphenols indirectly benefit the brain by improving the health of the vascular system that supplies it. By improving the blood vessel function as well as lowering the blood pressure, an enhanced cerebral blood flow results. This ensures better delivery of oxygen and nutrients to the brain. This improved blood flow can also promote vascularization and neurogenesis (the creation of new nerve cells) in areas important for cognition, such as the hippocampus.

Mood

Some polyphenols act as reversible inhibitors of monoamine oxidase (MAO), an enzyme that breaks down neurotransmitters. By inhibiting MAO, they can increase the amounts of neurotransmitters like dopamine, serotonin, and noradrenaline in the brain tissue, suggesting a role in mood regulation and potentially in addressing anxiety or depression.

Bioavailability

A key challenge in maximizing the therapeutic potential of polyphenols is their low bioavailability. Only small quantities are typically absorbed into the bloodstream. This makes crossing the already difficult Blood-Brain Barrier (BBB) even more limited. Despite this, the evidence suggests that sufficient amounts of active compounds or their beneficial metabolites do reach the brain to exert the observed positive effects when part of a daily intake.

MIND

The evidence of the beneficial impact of polyphenols on brain health, has lead a number of neurologists to create a dietary recommendation. They used two, nearly similar food recommendations as their basis: the Mediterranean diet and DASH (dietary approach to stop hypertension -a diet created by cardiologists). The result is MIND: Mediterranean-DASH Intervention for Neurodegenerative Delay. This is a hybrid diet developed by researchers at Rush University Medical Center specifically to lower the risk of dementia and slow the decline of brain health. (Note the importance of DASH, i.e. low blood pressure is essential for brain health).

Food for Thought

If the above summary of scientific research has got you thinking about eating healthy, here are the top neuroprotective foods

Berries (Blueberries, Strawberries, Acai, Blackcurrants)

Berries are rich in anthocyanins, which cross the blood-brain barrier and accumulate in brain regions vital for learning and memory (like the hippocampus). They enhance communication between neurons and boost Brain-Derived Neurotrophic Factor (BDNF). Studies show they can improve memory and executive function in older adults.

Dark Chocolate (>70% cocoa)

Cocoa contains epicatechin, which is highly effective at increasing blood flow to the brain (cerebral perfusion), which improves oxygen and nutrient delivery. This enhances attention, speed of processing, and working memory.

Green Tea

The Epigallocatechin Gallate (EGCG) in green tea is a powerful antioxidant that protects neurons from damage. It has been shown to reduce the formation of amyloid-beta plaques associated with Alzheimer’s disease and is a key factor in reducing oxidative stress and inflammation.

Turmeric

This yellow spice contains curcumin which is famous for its strong anti-inflammatory properties. Preclinical studies suggest it may help reduce beta-amyloid accumulation (Alzheimer’s plaques) and protect brain cells. Its absorption is greatly improved when consumed with black pepper (which contains piperine) or fat (eg olive oil).

Grapes/Red Wine

Probably the best known polyphenol is resveratrol, which you will find in rhubarb, grapes and its derivative red wine. Resveratrol activates sirtuins, proteins associated with DNA repair and cellular longevity. It helps preserve cognitive function and is noted for its ability to reduce oxidative stress and neuroinflammation.

Olive Oil

A bitter taste is evidence that olive oil contains oleuropein. Together with hydroxytyrosol, it contributes to the cardiovascular benefits of the Mediterranean diet, helping to maintain healthy blood pressure and endothelial function, which directly ensures proper blood flow to the brain.

To get the widest range of benefits, focus on eating a diverse and colorful diet rather than focusing on a single food. Different colors represent different classes of polyphenols, each offering a unique pathway for neuroprotection.