Varied diet rich in berries, green tea, pure cocoa, extra virgin olive oil, pomegranate, nuts.
A diet rich in polyphenols (berries, blood orange, pomegranate, green tea, apples, dark chocolate) reduced zonulin (a marker of permeability) and increased beneficial gut bacteria in older adults.
View the study (RCT) →Blueberry anthocyanins improve flow-mediated dilation in a dose-dependent way; regular consumption lowers blood pressure in people at cardiovascular risk.
View the study (RCT) →Improvements in attention and psychomotor speed with anthocyanin supplementation in young and middle-aged adults.
View the study (meta-analysis) →A combination of rosmarinic acid (rosemary) and EGCG (green tea) improved sleep quality and reduced insomnia severity.
View the study (RCT) →*⏱ 4 min read
Polyphenols are a group of antioxidant compounds found in a wide variety of plants consumed as foods and beverages, and are one of the most common classes of bioactive compounds in the plant kingdom, along with alkaloids, organosulfur compounds, and terpenoids; a growing body of evidence suggests that polyphenols have disease-fighting properties, although the quality of the evidence supporting these claims varies considerably depending on the condition studied and the type of polyphenol.
Chemically, polyphenols comprise organic compounds containing two or more phenolic rings with double bonds capable of donating electrons to oxidative compounds such as superoxide and peroxyl radicals, neutralizing free radicals and conferring their potent antioxidant properties; the main classes include phenolic acids, flavonoids, stilbenes, and lignans, the most common in the standard diet being the flavanols of tea, flavonols such as quercetin, the hydroxycinnamic acids of coffee, and the blue-purple anthocyanins of blueberries.
For gut health, a randomized crossover controlled trial with 51 adults over age 60 showed that a diet rich in polyphenols derived from berries, blood oranges, pomegranate juice, green tea, apples, and dark chocolate reduced levels of zonulin, a biomarker of impaired intestinal barrier function, and increased levels of beneficial gut bacteria, with cocoa and green tea metabolites associated with higher butyrate levels and better overall gut health.
For cardiovascular health, blueberry anthocyanins improved flow-mediated dilation, a measure of vascular endothelial function, in a dose-dependent manner in an analysis of four studies with 60 participants, with effects similar to those of whole wild blueberry; consuming blueberries twice a day for one month also increased flow-mediated dilation over the long term, and in adults at cardiovascular risk, prolonged berry supplementation also lowered blood pressure, although not in healthy adults, which indicates individual differences in response.
For cognitive function, several studies found improvements in attention and psychomotor speed with anthocyanin supplementation in young and middle-aged adults, with short-term supplementation being sufficient to produce benefits in attention and psychomotor speed, but long-term supplementation being the best option for memory; and for sleep, a combination of rosmarinic acid from rosemary and EGCG from green tea improved sleep quality and reduced insomnia severity in adults with poor sleep in a 30-day study.
⏱ 4 min read | Tags: Brain, Green tea, Alzheimer's, Diabetes, Polyphenol
Our brains shrink as we age, but that doesn't mean we should wait until old age to worry about it: neurodegeneration begins 15-20 years before the onset of symptoms of mild cognitive impairment, dementia, or Alzheimer's, with structures such as the hippocampus especially vulnerable to the accumulation of neurofibrillary tangles, the loss of synapses, and the neuronal death that precede clinical symptoms by decades.
Glucose levels in the high-normal range are associated with hippocampal atrophy, and the damage is even greater in people with metabolic dysfunction or diabetes, which is why Alzheimer's is sometimes called type 3 diabetes; glucose control is a modifiable risk factor for cognitive decline, and polyphenols, plant compounds with potent antioxidant and anti-inflammatory properties, can improve both metabolic and brain function at the same time, offering a practical dietary path to protect cognitive health over the long term.
To determine the effects of a polyphenol-rich Mediterranean diet on metabolic and brain health, a randomized study assigned participants to one of three diets for 18 months: a standard Mediterranean diet, a Mediterranean diet enriched with 3-4 cups of green tea per day and a polyphenol-rich green smoothie containing Mankai, a duckweed-based product with more than 200 polyphenols including luteolin and apigenin, or a healthy control diet based on general dietary guidelines.
Participants who consumed the polyphenol-rich Mediterranean diet experienced less brain aging, assessed by hippocampal MRI, than the other groups; the polyphenol-enriched diet also produced larger improvements in glycemic control, with 58% of participants in that group improving versus 32% and 29% in the other groups; and participants who consumed the green smoothie more than 3 times per week and green tea 2 or more times per week showed the greatest improvements in biomarkers of glycemic control such as fasting glucose and HbA1c.
Information, not medical advice. Scientific evidence reflects the quality of the studies.