In this episode we will talk about a new study from the University of California, Irvine shows that compounds in both green and black tea relax blood vessels by activating ion channel proteins in the blood vessel wall. We will also talk about a national study that shows health declining in Gen X and Gen Y
Gen X – 1965 – 1980
Gen Y – 1981 – 1996
Gen Z – 1997 – 2015
The discovery helps explain the antihypertensive properties of tea and could lead to the design of new blood pressure-lowering medications.
Since its initial use in China over 4000 years ago, tea has become one of the most commonly consumed beverages worldwide, second only to water. Upwards of 2 billion cups of tea are currently drunk each day worldwide
The leaves of the evergreen species Camellia sinensis are used to make the most prevalent caffeinated teas. Since they are produced from the same plant, the differences between tea varieties (green, oolong, and black) are due to leaf fermentation levels (unfermented, partially fermented, and fully fermented, respectively), which impart the characteristic properties and flavors of the teas.
Results from the research revealed that two catechin-type flavonoid compounds (epicatechin gallate and epigallocatechin-3-gallate) found in tea, each activate a specific type of ion channel protein named KCNQ5, which allows potassium ions to diffuse out of cells to reduce cellular excitability. As KCNQ5 is found in the smooth muscle that lines blood vessels, its activation by tea catechins was also predicted to relax blood vessels
“We found by using computer modeling and mutagenesis studies that specific catechins bind to the foot of the voltage sensor, which is the part of KCNQ5 that allows the channel to open in response to cellular excitation. This binding allows the channel to open much more easily and earlier in the cellular excitation process,” explained Abbott.
As many as one-third of the world’s adult population has hypertension, and this condition is considered to be the number one modifiable risk factor for global cardiovascular disease and premature mortality
In addition to its role in controlling vascular tone, KCNQ5 is expressed in various parts of the brain, where it regulates electrical activity and signaling between neurons. Pathogenic KCNQ5 gene variants exist that impair its channel function and in doing so cause epileptic encephalopathy, a developmental disorder that causes frequent seizures. Because catechins can cross the blood-brain barrier, the discovery of their ability to activate KCNQ5 may suggest a future mechanism to fix broken KCNQ5 channels to improve brain excitability disorders stemming from their dysfunction.
Abstract taken from the study
Background/Aims: Tea, produced from the evergreen Camellia sinensis, has reported therapeutic properties against multiple pathologies, including hypertension. Although some studies validate the health benefits of tea, few have investigated the molecular mechanisms of action. The KCNQ5 voltage-gated potassium channel contributes to vascular smooth muscle tone and neuronal M-current regulation. Methods: We applied electrophysiology, myography, mass spectrometry, and in silico docking to determine the effects and their underlying molecular mechanisms of tea and its components on KCNQ channels and arterial tone. Results: A 1% green tea extract (GTE) hyperpolarized cells by augmenting KCNQ5 activity >20-fold at resting potential; similar effects of black tea were inhibited by milk. In contrast, GTE had lesser effects on KCNQ2/Q3 and inhibited KCNQ1/E1. Tea polyphenols epicatechin gallate (ECG) and epigallocatechin-3-gallate (EGCG), but not epicatechin or epigallocatechin, isoform-selectively hyperpolarized KCNQ5 activation voltage dependence. In silico docking and mutagenesis revealed that activation by ECG requires KCNQ5-R212, at the voltage sensor foot. Strikingly, ECG and EGCG but not epicatechin KCNQ-dependently relaxed rat mesenteric arteries. Conclusion: KCNQ5 activation contributes to vasodilation by tea; ECG and EGCG are candidates for future anti-hypertensive drug development.
Health declining in Gen X and Gen Y, national study shows
Recent generations show a worrying decline in health compared to their parents and grandparents when they were the same age, a new national study reveals.
Compared to previous generations, they showed poorer physical health, higher levels of unhealthy behaviors such as alcohol use and smoking, and more depression and anxiety.
Hui Zheng conducted the study with Paola Echave, a graduate student in sociology at Ohio State. The results were published March 18, 2021, in the American Journal of Epidemiology.
The researchers used data from the National Health and Nutrition Examination Survey 1988-2016 (62,833 respondents) and the National Health Interview Survey 1997-2018 (625,221 respondents), both conducted by the National Center for Health Statistics.
To measure physical health, the researchers used eight markers of a condition called metabolic syndrome, a constellation of risk factors for heart disease, stroke, kidney disease, and diabetes. Some of the markers include waist circumference, blood pressure, cholesterol level, and body mass index (BMI). They also used one marker of chronic inflammation, low urinary albumin, and one additional marker of renal function, creatinine clearance.
Abstract of results:
- The magnitude of the increase is higher for White men than other groups (mainly increase in metabolic syndrome), while Black men have the steepest increase in low urinary albumin (a marker of chronic inflammation).
- The presence of a small amount of albumin in the urine may be an early indicator of kidney disease.
- Whites undergo distinctive increases in anxiety, depression, and heavy drinking, and have a higher level than Blacks and Hispanics of smoking and drug use in recent cohorts. Smoking is not responsible for the increasing physiological dysregulation across cohorts.
- The obesity epidemic contributes to the increase in metabolic syndrome, but not in low urinary albumin. The worsening physiological and mental health profiles among younger generations imply a challenging morbidity and mortality prospect for the United States, one that may be particularly unfavorable for Whites.
- Results showed that levels of anxiety and depression have increased for each generation of whites from the War Babies generation (born 1943-45) through Gen Y.
- While levels of these two mental health indicators did increase for Blacks up through the early Baby Boomers, the rate has been generally flat since then.
- For whites and Blacks, the probability of using street drugs peaked at late-Boomers (born 1956-64), decreased afterward, then rose again for late-Gen X. For Hispanics, it has continuously increased since early Baby Boomers.
Why is American Health Declining?
Data from past decades showed that U.S. life expectancy began to lose pace with that of other countries starting in the 1980s. Historically this was the beginning of the opioid epidemic, the shrinking of the middle class, and the widening of income inequality. Maybe this is happening due to the lack of support for struggling families?
Studies suggest this is related to drug overdoses, suicides, alcohol-related illnesses, and obesity are largely to blame.
The US had been making steady progress. Life expectancy increased by nearly 10 years over the last half-century – from 69.9 years in 1959 to 78.9 years in 2016.
But the pace of this increase slowed over time, while other high-income countries continued to show a steady rise in life expectancy.
After 2010, US life expectancy plateaued and in 2014 it began reversing, dropping for three consecutive years – from 78.9 years in 2014 to 78.6 in 2017. This is despite the US spending the most on health care per capita than any other country in the world.