Can Green Tea Preserve the Brain Better than Coffee?

 Does green tea protect the aging brain better than coffee? In this episode of Daily Value, we look at the evidence behind green tea's impact on brain aging, focusing on cerebral white matter lesions, Alzheimer’s risk, and brain atrophy. Drawing on studies like Shibata et al.'s recent publication in Science of Food (PMID: 39774601), we discuss how a certain threshold of green tea, but not coffee is associated with less white matter lesions in aged individuals.

Discussion Points:

• MRI findings on green tea’s association with reduced white matter lesion progression in older adults consuming a specific amount of cups daily.
• Past research observing a 5% reduction in hippocampal atrophy rate in green tea consumers (amounts discussed in episode).
• Brewing techniques and supplement tips to optimize EGCG content and/or minimize caffeine content of tea.

https://pubmed.ncbi.nlm.nih.gov/39774601/ 

Transcript

Speaker 0: 0:00

Does green tea protect the aging brain better than coffee? Hello everyone, and welcome to this episode of Daily Value. I'm William Wallace and today we'll explore the compelling evidence surrounding green tea consumption and its impact on brain aging, specifically focusing on cerebral white matter lesions, alzheimer's disease risk and brain atrophy with age. Our discussion draws from three recent studies, each providing unique insights into the potential of green tea as a neuroprotective agent. Now, coffee and tea are two of the most widely consumed beverages worldwide. At this point, there is enough evidence to suggest that both have neuroprotective properties attributed to their bioactive compounds, the primary ones being chlorogenic acids and caffeic acid for coffee and catechins for green tea, one of the most prominent and most studied being epigallocatechin gallate, also known as EGCG. These compounds are of particular interest to the research community on how they affect and can be used for protecting the aging brain.

Speaker 0: 1:10

Aging by itself is a major risk factor for dementia. Aging naturally results in brain atrophy, along with functional and structural changes, both of which can occur first and cause the other, that being functional and structural changes to the brain. Now, aging itself is not a sufficient explanation for why or how these things happen. To dig into the weeds there would create an episode longer than this 8-10 minute format is meant to support. But one thing that does accompany aging that can help to explain some changes resulting in cognitive decline are the accumulation of white matter lesions. White matter consists of nerve fibers known as axons, covered in myelin, which helps transmit signals between different parts of the brain and spinal cord. A white matter lesion is an area of damage or abnormality in the white matter of the brain. They are indicative of cerebral small vessel disease, which is associated with vascular dementia. Cerebral small vessel disease is caused by the narrowing or obstruction of small blood vessels in the brain due to inflammation and or a buildup of damaged proteins and or a buildup of damaged proteins. Actually, about 25% of strokes are classified as small vessel, and cerebral small vessel disease is the most common cause of vascular cognitive impairment. Now, larger white matter lesions are associated with more severe brain atrophy in patients With Alzheimer's disease. However, the presence of white matter lesions alone is a risk factor for cognitive decline, even when accounting for other Alzheimer's risk factors.

Speaker 0: 2:51

The greatest risk factor for accumulating white matter lesions is hypertension or having elevated blood pressure. This is where green tea comes in, as it has been shown consistently in the literature to help reduce blood pressure, both in hypertensive populations and borderline hypertensive populations. Interestingly, green tea has been shown to be more effective in lowering blood pressure compared to black tea and coffee. The primary active components of black tea are theaflavins and in most cases theaflavins have been shown to be at least equally as effective as catechins from green tea in health promotion outcomes, but when it comes to blood pressure lowering effects, green tea does have a slight advantage. As for coffee, green tea has less caffeine than coffee. Caffeine, we know, especially too much, can have negative impacts on blood pressure.

Speaker 0: 3:46

Now a study published this month in the journal Science of Food by Shibata et al looked at the association between green tea consumption and cerebral white matter lesions in older adults. This study evaluated 720 community dwelling individuals age 60 and above and used MRIs to quantify lesion volumes. The findings revealed that higher green tea consumption was inversely associated with the progression of white matter lesions. Specifically, individuals consuming at least three cups per day exhibited a statistically significant reduction in lesion volume compared to those drinking under one cup per day. The proposed mechanism involves the catechins we touched on, particularly epigallocatechin gallate, or EGCG, which exhibits antioxidant properties, reducing oxidative stress and mitigating vascular damage, which is a pivotal factor in lesion development. Building on this, there was a longitudinal study published in 2021 that demonstrated that higher green tea consumption was associated with a 5% reduction in the annual rate of hippocampal atrophy for every additional 100 milliliters of daily intake. In 40 to 89-year-olds, 100 milliliters is equivalent to just under half a cup of green tea, suggesting that it does not take a lot of green tea intake to reap some cognitive benefits in this particular population.

Speaker 0: 5:16

Now an all important question how best to use green tea or incorporate it into your routine. Well, brewing can be a consideration for maximizing the EGCG content of your tea. After all, brewing is a water-based extraction technique. Here are the instructions Use 1.5 to 2 grams of high-quality green tea leaves or one standard teabag. Heat 250 milliliters approximately one cup of water to just below boiling, that's around 176 degrees Fahrenheit to about 105 degrees Fahrenheit. Steep the tea leaves or tea bag for three to five minutes. Avoid exceeding this time to prevent excessive bitterness.

Speaker 0: 5:59

For optimal results, use soft, low mineral water, as hard water can inhibit catechin extraction and alter the tea's flavor profile. So using distilled water is better in this case. There's also cold brewing for lower caffeine content. To do this, place two grams of green tea leaves in approximately two cups of cold water. Allow the tea to steep in the refrigerator for 8 to 12 hours. This method extracts catechins while minimizing caffeine content, resulting in a milder flavor as well. There are also green tea supplements. Choose green tea extract supplements that clearly indicate catechin or EGCG content and usually aiming for 300 to 600 milligrams of catechins daily. That's shown to produce cardiovascular and neuroprotective benefits, but be sure not to go over this amount. Verify third-party testing to ensure product quality and safety.

Speaker 0: 6:56

A couple practical tips If using teabags, opt for biodegradable materials to minimize microplastic contamination. An option for avoiding microplastic contamination from teabags is to use loose tea in a metal filter like a tea ball infuser. You can rinse tea leaves briefly in boiled water for five seconds or so before brewing to reduce potential pesticide residues by up to 10%. The implications of the health impacts of tea consumption can be profound, particularly for aging populations at risk of cognitive decline. Regular green tea consumption may represent an accessible, non-invasive strategy for preserving brain health. However, it's important to emphasize that these benefits should be viewed as complementary to other interventions, including, like always, a balanced diet, regular physical activity and actual cognitive engagement. In conclusion, the convergence of data from these studies does underscore Green Tea's potential as a neuroprotective agent with promising applications in mitigating brain aging and supporting cognitive function. Thank you for tuning into this episode of Daily Value. If you found today's discussion valuable, please share it with your colleagues and subscribe for more insights into the science of nutrition. Until next time, stay informed, stay healthy.