Pu-erh tea, from the land of Shangri-La, has now been confirmed to produce …
New research discloses that China’s
legendary tea significantly improves cholesterol while reducing weight
By Will Block
Tea is a cup of life.
egends are often useful guides to metaphorical truth, yet rarely do they yield literal truth. But when they do … the results can be enlightening. Think of Homer’s epic story of Odysseus (circa 800 BCE) in which memory is restored by a plant (containing galantamine), something that didn’t make scientific sense until the later part of the 20th Century.
Another myth to commemorate takes us back further in time: About 5,000 years ago the Chinese Emperor Shennong—to whom the invention of agriculture and Chinese medicine is attributed—was boiling a caldron of water kindled by twigs from a nearby tree, when a few of its leaves were carried up by the hot air and into the simmering water. Upon sipping the infusion, Shennong was surprised and delighted by its flavor and restorative properties. Later, while testing the medicinal properties of various herbs (some of which were poisonous) on himself, the Emperor determined that the astounding brew worked as an antidote, and moreover that it offered a wide array of health benefits. The leaves that had blown into the caldron were tea leaves (Camellia sinensis), and what Shennnog found was among the greatest food discoveries of all times. Legendary health benefits have given way to truth, and to this day new scientific findings are still arriving.
The Waters of Shangri La
In China’s Yunnan province, legends abound. So much so that the northern-most county in this southern-most of all provinces has been renamed Shangri-La (previously it was known as Zhongdian). Into this county—after crossing the Tibetan plateau, turning south, and traveling in parallel for many hundreds of miles—pour three great rivers of the world: the Salween, the Mekong, and the Yangtze. Soon after entering Yunnan the rivers diverge, but not until they’ve passed through Shangri-La, continuing their sculpturing of the land to create what are known as The Great River Trenches of Asia.
Almost Immortal, Living Far
Beyond the Normal Lifespan
The larger-than-life Austrian-American explorer Joseph Rock lived in Zhongdian county near the town of Lijiang, an apex of the famed Tea-Horse Road (more about this later), for nearly 30 years (1922-1949) and ventured repeatedly throughout Yunnan, Sichuan, and Tibet where he studied the people, their languages and the flora. Yunnan is probably the most biologically diverse temperate zone in the world. Out of approximately 30,000 species of higher plants in China, Yunnan has over 50%, or about 17,000.
During his Yunnan years, Rock wrote ten articles for National Geographic magazine about his expeditions into these regions of revered peaks and little-traveled areas including the extraordinary Salween River trench. It was from reading these articles, it is said, that James Hilton was inspired to write his novel Lost Horizon, about a remote community known as Shangri-La where the inhabitants are almost immortal, living far beyond the normal lifespan and only changing, with age, very slowly in appearance. While any place that truly resembles Shangri-La is an unsubstantiated myth, there are significant health benefits to be gained from one of the main food products of the region.
Yunnan’s Special Health-Promoting Tea
Tea is thought to have originated in Yunnan. One of Yunnan’s most famous products is Pu-erh (pronounced poo·air) tea, named after the old tea-trading town of Pu’er. Pu-erh is a type of tea made from a broadleaf variety of the tea plant known as Camellia sinensis var. assamica. Generally speaking, there are four types of tea: white tea, green tea, oolong tea, and black tea. White tea, the rarest, is a delicate tea made from the tree’s young buds (the lower-quality whites also include some leaves), whose downy, silvery hairs make them appear white in the sunlight; the buds are processed with no fermentation.
The other three teas are made from the tree’s leaves, but with different degrees of fermentation (an oxidative process) before they’re dried and packaged. Like white tea, green tea is made with no fermentation, and it has a grassy freshness that holds great appeal. Oolong tea is made from partially fermented leaves and is considered by many to be the “champagne” of teas. Black tea is made from fully fermented leaves and has a stronger character (and darker color) than the others. In these different processing methods lie important differences in the chemical composition, and hence the medicinal qualities, of the teas in question.
The Pu-erh Difference
Pu-erh is different: although it’s made as a green tea, it’s much better known for being made as a fully fermented tea that’s analogous to black tea. Although the result is a black type of tea, the processing method used is unique to Pu-erh, and the tea is unlike black tea in some ways. Actually, two processing methods are used, one of ancient origin and one of recent invention. Thus there are really three kinds of Pu-erh tea:
- Green Pu-erh (aka raw or uncooked Pu-erh). As with any other green tea, the freshly picked leaves are heated briefly to inactivate the tea enzymes that cause fermentation; this prevents the tea from becoming an oolong tea or a black tea, which are made by the fermentation of leaves that have not been heated. Green Pu-erh is sold as loose leaves for consumption immediately or after a brief aging period.
- Aged raw Pu-erh (aka secondary oxidation/ fermentation Pu-erh). More often, the heated green tea leaves described above are lightly steamed and compressed into cakes of various sizes and shapes, to be aged anywhere from a few years to a few decades before consumption. During the aging period, oxidative and microbial processes slowly ferment the tea, producing a strongly fermented black-type tea (but it’s not called black). These processes alter the tea’s chemical composition in ways that improve the tea with age; they also confer on the tea some remarkable health benefits, particularly in the area of fat reduction. Aged raw Pu-erh is the most highly prized of all teas by connoisseurs, who believe that the longer the aging, the better the tea; individual cakes weighing about a pound can fetch hundreds or even thousands of dollars.
- Black Pu-erh (aka ripened, fermented, or cooked Pu-erh). This much more affordable tea is called black, although it too is not made by the traditional black-tea process. Instead, the heated green tea leaves are subjected to an artificial aging process, invented in China in 1972, resembles
composting; it induces microbial fermentation to the black state much more quickly and efficiently than in aged raw Pu-erh. The fermented leaves are sold loose or are compressed into cakes for further aging for a few years. Although it does not match aged raw Pu-erh in quality, black Pu-erh is still considered a good tea.
The Inadvertent Agent of Aging
The chemical composition of Pu-erh that results from aging* and enhances the quality of the tea (other teas do not age well and are best drunk as young and fresh as possible), probably arose inadvertently. For more than a millennium, an ancient road resembling the famed Silk Road wound its way through the mountains of Southwest China, bridging the Chinese provinces and the Tibet Plateau. Along its rugged road, various commodities including salt, sugar, and tea flowed into Tibet, carried typically by horses. This ancient trade passage, dubbed the “Tea-Horse Road,” first appeared about 1,500 years ago, during the Tang Dynasty (618-907), and lasted until recently when Tibetan highways were constructed. It is thought that the Pu-erh tea was originally formed into cakes to enable it to compactly travel to Tibet. All the better for our story, because without the aging process promoted by the cakes, the diverse chemical properties that give Pu-erh its legendary medicinal properties may not have evolved.
The environmental factors that affect the aging are much more diverse and variable than those for wine and are critical to the teas’ proper development. The tea leaves are graded on a ten-point quality scale, and the products are also usually identified by such factors as the year and season of harvest and, of course, the regional source. Much value is placed on favorable terroir (a term well known to wine lovers), which means the “essence of a place”—the combined effects of its topography, soil, microclimate, cultivation practices, etc. Also of great importance is the tea factory (akin to a winery) where the leaves are processed and compressed into “cakes” of various sizes and shapes. Most cakes weigh anywhere from about half a pound to a few pounds.
Recently, Pu-erh tea became exceedingly popular in China, and a few years ago experienced a price bubble (see sidebar, “The Pu-erh Bubble”) that collapsed, with the result that prices dropped to pre-boom levels. Our interest in Pu-erh lies in its health benefits, which rise above all other teas and include the ability to suppress fatty acid synthesis (see
“Fighting Fat with Pu-erh Tea” in the July 2007 issue), which new evidence shows can help prevent weight gain and consequently obesity.
The Pu-erh Bubble
Long ago in China, tea was often an integral component of immortality potions favored by Taoists, who were keen on the subject. The echo of those beliefs—that tea drinking helps one to live to a ripe old age—lives on. While tea is no fountain of youth, its benefits certainly contribute to longevity . . . and prosperity, you would think, especially if you live in Yunnan, and especially if you are financially involved in promoting Pu-erh as a beacon of health. But as with many hasty perceptions—powerless until their time has come—the Yunnanese were swept up in a seemingly endless rising tide.
Over the last decade, as China went nuts over Pu-erh tea, prices rose by as much as 10 fold driving up the cost of the best fermented Pu-erh to $150/lb! Overnight, great riches were bestowed upon growers and producers in Yunnan, enabling the purchase of cars, flat screen TVs, and private education for their children. So tempting was the belief in Pu-erh’s ascendency that personal savings were plowed back into black cakes of the compacted tea. Then, with the fragility of the world economy, it all went Poof! With the collapse, prices returned to those existing before the boom, making Pu-erh an even greater bargain. And with returns as beneficial as the current research indicates, price is no longer an object of concern, as it was thought to be during the bubble.
- Jacobs A. A county in China sees its fortunes in tea leaves until a bubble bursts. The New York Times, January 16, 2009.
A Profound Tool for Dramatic Body and
A recent study tested Pu-erh’s effects on weight gain, blood lipids, oxidative damage, and antioxidant enzymes. Using 80 hyperlipidemic rats, the positive results on all fronts were resounding, with the highest benefits attributed to the largest amount of Pu-erh consumed. The principal outcome of the study was the finding that Pu-erh tea can dramatically reduce weight gain and LDL (the bad cholesterol) build up, thus rendering it a profound tool for preventing pathologies associated with hyperlipidemia.
At the beginning of the study, 10 of the rats were designed as controls and given a standard Purina rat-chow diet, while the remaining 70 received the same chow to which had been added pig oil, egg yolk, cholesterol, and bile salt. The additives represented about 22% of the diet. After 10 days, blood lipid levels were measured, and all 70 met hyperlipidemic levels, the criteria of the experiment. These were divided into 7 groups of 10 rats each, the first group serving as controls and the balance given either fermented Pu-erh or unfermented Pu-erh tea extract (black Pu-erh or green Pu-erh) in the amounts of 0.5, 1.5, or 3.0 mg/kg of body weight. After 30 days of treatment, blood was collected for analysis.
Cholesterol and Enzyme Measurement
Serum levels of total cholesterol (TC), HDL (the good cholesterol), and triglycerides (TG) were measured along with LDL (the bad cholesterol). Also, the arteriosclerosis index (AI) was calculated using the formula: AI = (TC – HDL)/HDL. At the same time, the activities of serum antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and malondialdehyde (MDA), a marker for oxidative stress, were determined.
The researchers also analyzed and compared the levels of polyphenols and polysaccharides in fermented and unfermented Pu-erh teas. The fermentation process significantly reduced the tea’s polyphenols, compared to unfermented Pu-erh tea. By contrast, polysaccharides were substantially increased in the fermented tea. Of further note, the natural levels of ascorbic acid were not affected in the unfermented tea; however, the alpha-tocopherol levels were increased in the fermented tea.
Pu-erh Decreases Body Weight,
Independent of Food Intake
As expected, the control group of rats on the hyperlipidemic diet gained significantly more weight during the study than those fed a normal chow diet. However, of the groups fed the hyperlipidemic diet, only the group treated with the highest dose (3 g/kg) of fermented Pu-erh tea extract exhibited a remarkably reduced weight gain over the course of the study, compared to the control-treated hyperlipidemic group (see Figure. 1). Not so for the lower doses of Pu-erh tea, fermented or unfermented. Interestingly, food intake did not vary among groups with or without tea treatments. This indicates that reduced weight gain with the highest tea extract dose was not through fewer calories consumed. In other words, Pu-erh reduced the body weight independently of food intake in hyperlipidemic rats.
Pu-erh Reduces Lipoproteins,
Total cholesterol and Triglycerides
Also as anticipated, TC and TG levels were consistently higher in rats fed the hyperlipidemic diet, compared to the control group. All amounts of either Pu-erh tea significantly lowered TC. However, only the highest level of Pu-erh lowered TG levels to that of the normal chow diet group. The other two amounts of the tea extract lowered TG by a proportional amount. These effects were dose-dependant.
Unfermented Pu-erh lowered TC by an equal amount, about 1/3, in each group compared to controls, showing dose-independency. On the other hand, fermented Pu-erh lowered TC by 17%, 32% and 43% when treated with 0.5, 1.5 and 3.0 g/kg, respectively. Both fermented and unfermented Pu-erh reduced TC in hyperlipidemic rats, although this effect was most evident with the highest doses of fermented Pu-erh.
Unfermented Pu-erh lowered TG substantially by 42% and 58% after the rats had been treated with 1.5 and 3.0g/kg, respectively. As was observed with TC, only the highest dose of fermented Pu-erh significantly lowered TG by a sizable amount. Thus, unfermented Pu-erh may have a slightly more potent effect in this regard.
Pu-erh Improves Serum Lipoprotein Profiles
Pu-erh consumption increased levels of HDL and the ratio of HDL to TC. Treatment with unfermented Pu-erh for 30 days increased HDL by 58%, 95% and 98%, respectively, compared to control hyperlipidemic rats. Treatment with the doses of fermented Pu-erh increased serum levels of HDL by 61%, 91% and 146%, respectively. That’s a big wow! In animals treated with either tea extract, a greater proportion of TC was comprised of beneficial HDL. This effect was observed even in groups treated with doses that produced only modest, but significant, reductions in TC. The greatest effect was seen in the group treated with the highest dose of fermented Pu-erh.
Both Pu-erh tea extracts greatly reduced serum LDL levels. Unfermented Pu-erh reduced levels by 65%, 70% and 67%, respectively, compared to the controls. Similarly, but with a closer correlation to dose, fermented Pu-erh reduced levels of LDL by 43%, 67%, and 90%, respectively, compared to the controls. The best effect was observed in the highest dose of fermented Pu-erh, which produced levels of LDL that were even lower than those measured in the normal chow diet group.
Pu-erh Reduces Oxidative Damage
The diet-induced hyperlipidemia in the control group resulted in significant decreases in the protective antioxidant enzymes SOD and GSH-Px, while elevating the lipid peroxidation product MDA. Yet after treatment with unfermented Pu-erh, the serum levels of SOD were increased by 9.5%, 30.51% and 47.10, respectively. This effect was much greater in with fermented Pu-erh, producing levels of SOD that were 45.89%, 25.80% and 60.98%, respectively. Again, these effects were more pronounced with fermented Pu-erh.
Moreover, GSH-Px levels were enhanced by 219%, 238% and 244%, respectively, with unfermented Pu-erh and 208%, 216%, and 278%, in the fermented Pu-erh groups at respective escalated doses. As one would expect with higher levels of circulating anti-oxidation enzymes, MDA levels were significantly decreased in the rats treated with unfermented Pu-erh (51%, 48% and 56%) and fermented Pu-erh (59%, 55%, and 59%). These results were independent of dose.
Figure 1. Within the groups fed the hyperlipidemic diet, only the group treated with the highest dose (3g/kg) of daily administration of fermented Pu-erh tea extract exhibited a remarkably reduced weight gain over the course of the study, compared to the control-treated hyperlipidemic group.
Daily Use of Pu-erh is Beneficial for Health
At last we have a study that demonstrates health benefits from daily oral consumption of Pu-erh tea, albeit a rat hyperlipidemic model. Its principal finding, that Pu-erh tea can dramatically reduce weight gain and LDL buildup, is impressive because of the pathologies associated with hyperlipidemia. And Pu-erh tea has other beneficial effects, including its reduction of lipid oxidation, making it anti-atherogenic.
Significantly, these results strongly suggest that drinking steeped Pu-erh teas can provide the same beneficial constituents and the same benefits for humans. In the estimation of the researchers, maximal benefit can be obtained through either daily consumption of concentrated Pu-erh, or the ingestion of an equivalent dose of more dilute tea drinks throughout the day.
Although the results were consistent with previous studies showing there are many biochemicals in tea that contribute to lowering serum levels of lipids and lipoproteins, there is an anomaly. This is because the polyphenols found in all tea leaves, including Pu-erh—which are believed to have hypolipidemic and antiobesity effects—are reduced by fermentation. What may provide an explanation are great increases in polysaccharides and statins, suggesting that these are most likely to be the major agents lowering LDL and TC. Other possible mechanisms may involve free amino acid and unsaturated fatty acids.
Reactive oxygen species (ROS) are hypothesized to be principal causative agents for a many human diseases, including cancer, atherosclerosis, and even aging. So it is extremely important to bolster one’s endogenous antioxidant defense system by removing ROS from excessive play. While there is insufficient evidence to support the belief that antioxidants can prolong life span, their benefit may certainly enhance the quality of life. The antioxidants that are known to be present in Pu-erh tea, including vitamin C and vitamin E, assuredly contribute to the robust protective effects against oxidative damage that have been observed.
Finally, Pu-erh tea offers what may be a synergic effect from its antioxidant constituents and induction of the antioxidative enzymes SOD and GSH-Px. It also reduces levels of MDA, a measure of peroxidation and oxidized LDL levels. All of these findings support the consumption of Pu-erh tea for hyperlipedemia-related and aging disorders based on its substantial effects of hypolipidemia and antioxidation.
Pu-erh—From Legend to Reality
While the ultimate research, directly involving humans, has yet to be done, the current rat study is remarkable. As the authors write, “It will be beneficial to repeat the studies . . . using specific fractions of Pu-erh tea extracts containing a limited number of constituents. To this end we are in the process of identifying fractions with robust activities and further fractioning to purify the responsible components. Both these crude and highly purified fractions will be tested in the hyperlipidemic rat model as well as additional models associated with the aging process.” To this end the legends have taken us, as have a growing number of user reports that Pu-erh may play an important key in slowing the speeding train toward obesity. Rather than waiting for the clinchers, we have a lot to gain (and lose!) by making this extraordinary tea a regular part of our daily diet.
- Hou Y, Shao W, Xiao R, Xu K, Ma Z, Johnstone BH, Du Y. Pu-erh tea aqueous extracts lower atherosclerotic risk factors in a rat hyperlipidemia model. Exp Gerontol 2009 Apr 5. [Epub ahead of print]
Will Block is the publisher and editorial director of Life Enhancement magazine.