Tea consumption increases bone density and reduces the risk of osteoporosis
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Results:
Our study was based on 17 journal articles, including 2 prospective cohort studies, 4 case–control studies, and 11 cross-sectional studies. In the present study, the total OR of osteoporosis for the highest versus the lowest categories of tea consumption was 0.62 (95% CI, 0.46–0.83), with significant heterogeneity among studies (I2 = 94%, P < .01). There was, however, no publication bias of the meta-analysis about tea consumption and osteoporosis. Subgroup analysis showed that tea consumption could reduce the risk of osteoporosis in all examined subgroups.Conclusion:
In the present study, it can be concluded from the results that tea consumption can reduce the risk of osteoporosis. -
Monitoring fluorine levels in tea leaves from major producing areas in China and the relative health risk
Abstract
The trace element fluoride can exert a preventive function on dental caries at moderate intake levels, but can also lead to skeletal fluorosis and cognitive impairment when consumed in excessive amounts. Tea is a fluoride hyperaccumulator, yet the risks of fluoride intake via tea consumption are yet to be investigated. In this study, we measured fluoride levels in common tea products from major cultivation provinces in China. Fluoride contents ranged from 6 to 808 mg/kg. Of the samples, 15.6% (34/218) demonstrated fluoride contents which exceeded the maximum residue limit of 200 mg/kg. The samples with high fluoride contents mainly represented oolong tea and dark tea. Fluoride contents in tea were significantly varied between producing regions, which is mainly due to different degree of soil acidification and fluoride occurrence in groundwater. Daily fluoride intake via tea consumption among the general population ranged from 0.02 to 2.20 mg/day, which is lower than the tolerable upper fluoride intake level (UL) of 3.50 mg/day based on Chinese Dietary Reference Intakes, but rather close to the UL of 2.50 mg/day set by the European Food Safety Authority. A risk assessment indicated that the consumption of tea was not associated with any significant health risks (hazard quotient ≤ 0.54). However, we found a potential risk for the simultaneous consumption of tea, drinking water, wheat and seafood based on a simulation assessment. Fluoride intake among the high-risk population should be continuously monitored.
https://www.sciencedirect.com/science/article/abs/pii/S0889157523000790The effects of green tea consumption on metabolic and anthropometric indices in patients with Type 2 diabetes
Conclusion:
Drinking four cups of green tea led to a significant reduction in weight and systolic blood pressure.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3908530/Shaded Japanese Green Teas
Shaded and unshaded teas refer to how the tea is cultivated in Japan. Shading, or kabuse, is done to reduce the sunlight that the tea plant receives by about 85%, which lowers the plant’s photosynthesis.To put it succinctly, shading is done to keep the L-theanine content high, and the formation of catechins low. L-theanine is responsible for the umami taste, whereas catechins are responsible for the tea tasting astringent or bitter.
Additionally, shading produces a sweeter leaf because of the higher sugar content. It also tends to create darker and greener leaves due to the plant creating more chlorophyll.
Shading is generally done for a short period (2 to 4 weeks) before the tea leaves are picked. For example, Kabuse Sencha is shaded for 2 weeks, Gyokuro for 3, and finally, Matcha for 4 weeks. Shading is done either directly on the top of the plant or more traditionally with shelf style shading. Shading is also only done in Japan.
https://obubutea.com/comparing-shaded-japanese-green-teas/ -
Given that leaves are rich in calcium, it makes sense that drinking tea helps with reducing the risk of osteoporosis. However, I think that just drinking tea regularly, as in all the time, may not give us all the daily calcium intake needed for meeting our daily calcium RDA.
It helps a lot though, but we still need calcium through milk and cheese consumption, as well as eating plenty of well-cooked green leaves as part of our meals.
It also helps if we emulate our cats and dogs in eating bones, but given that it's highly impractical as bones are tough, we can also consider eating anchovies and sardines where the bones are softened by cooking or simply fine enough that they're easier to chew on.
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@yerrag It's not the calcium amount but the stress-reducing bioactive compounds in tea having a positive effect on metabolism of bone/glucose.
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To put it succinctly, shading is done to keep the L-theanine content high, and the formation of catechins low. L-theanine is responsible for the umami taste, whereas catechins are responsible for the tea tasting astringent or bitter.
Additionally, shading produces a sweeter leaf because of the higher sugar content. It also tends to create darker and greener leaves due to the plant creating more chlorophyll.
I never quite understand the sweet vs bitter benefits of tea. So the tannins are undesirable from a taste profile but aren’t bitter qualities in foods considered medicinal in like traditional medicines. Like TCM etc. I even remember hearing Ray talk about bitter substances being great at stimulating the liver and bile production and whatnot. Does this just not really apply with green tea?
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That may be so, but I'm not sure if regularly tea drinking in itself will be able to provide enough calcium to prevent osteoporosis in later years. I see lots of elderly Chinese in Hongkong who have hunched backs. They drink plenty of tea.
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tea is very high in fluoride. The more expensive teas are harvested from young shoots, which are much lower in fluoride due to less time growing to accumulate it. But that is the issue, the cheaper assam teas can have 2mg per cup.
