Certain fruits and vegetables contain high amounts of polyphenols, which have been shown to protect against cardiovascular disease while significantly reducing the risk of cognitive decline and supporting healthy aging. Particularly beneficial polyphenols are special flavonoids.
A new study involving experts from Columbia University examined how polyphenols influence age-related cognitive decline and neurodegeneration. The results are published in the English-language journal “Nutritional Neuroscience”.
Aging healthily thanks to proper nutrition
Adhering to a Mediterranean or predominantly plant-based diet is known to promote healthy aging, including a reduced risk of age-related cognitive decline, the team explains.
The researchers explain that such diets contain a lot of fruit and vegetables, which are rich in polyphenols and also provide important fiber. In her opinion, these ingredients also play an important role in the beneficial effect on mental performance in old age.
What are polyphenols?
Polyphenols are large molecules produced by plants to protect them from environmental influences and injury. According to a previous review, polyphenols can generally be divided into two broad classes: flavonoids and phenolic acids.
The flavonoids are further divided into flavones, flavonones, flavonols, flavanols and isoflavones, while the phenolic acids are differentiated between hydroxybenzoic acid and hydroxycinnamic acid. Fruit peels are considered a particularly rich source of flavonoids.
Intestinal flora helps with absorption
However, after the human body absorbs polyphenols, only around five percent of these molecules are absorbed in the small intestine, explain the experts at Columbia University in their new study.
The intestinal flora makes a significant contribution here by converting the polyphenols into absorbable simple phenolic compounds. This also applies to the subgroup of flavonoids.
Flavan-3-ols are particularly healthy
Flavan-3-ols are a type of flavonoid that is mainly found in grapes, berries, pome fruit, tea and cocoa. These flavan-3-ols are known to have a beneficial effect on various risk factors for cardiovascular disease, reports the research group.
In addition, flavan-3-ols also have a positive influence on cognitive function and the brain regions involved in memory formation, the experts add.
There are already preclinical and clinical studies that attribute these positive effects on the brain and heart to, among other things, endothelial vascular effects and anti-inflammatory properties. Fruits and vegetables containing flavan-3-ols could be particularly beneficial for health.
Interaction with the intestinal flora
Interestingly, according to the researchers, it has also been shown that the polyphenols change the composition of the intestinal flora and are metabolized by different types of microbes. The positive effects are apparently related to changes in the intestinal microbiota.
It was already known that the intestinal flora can influence cognitive functions via the intestinal-brain axis, and intestinal microbiota also appear to play a role in the effect of polyphenols (specifically flavonoids and the subtype flavan-3-ols). (as)