The benefits of drinking Pu'er tea are a common topic among tea enthusiasts. Anecdotal evidence from friends, aggressive marketing by tea merchants, and health lectures by tea experts all touch on this subject. Since the 20th century, scientific research has delved into the medicinal properties and therapeutic mechanisms of tea, such as polyphenols, theaflavins, and L-EGCG. Although research on Pu'er tea started later, it has produced significant results. These findings suggest that the various phytonutrients in Pu'er tea can have real effects on human health.
Ancient and Modern Health Needs
In Tibetan folklore, there is a saying: “Cha is blood (tea nourishes the blood), Cha is flesh (tea sustains the body), Cha is life (tea is essential for living).” They have long believed that Pu'er tea is a powerful health Drink that can “counteract the toxicity of meat and dairy.”
During the Qing Dynasty, Pu'er tea's functions of “cutting through grease, aiding digestion, and sobering intoxication” were greatly promoted. It crossed mountains to become the supreme tribute tea in the Forbidden City, marking the first peak in Pu'er tea history. The reason for its popularity in the imperial court was due to the Manchu people, who were nomadic by origin and had a diet primarily consisting of meat. They needed Pu'er tea to aid digestion and improve their health.
Thanks to its prosperity in the capital, more people became aware of Pu'er tea. Works like “Records of Pu'er Tea” by Ruan Fu and “Supplement to Compendium of Materia Medica” by herbalist Zhao Xuemin documented Pu'er tea's potent functions. After the Qing Dynasty, Pu'er tea spread southward, reaching Southeast Asia and taking root in Hong Kong, where it was believed to help with fat reduction, weight loss, and even alleviate high blood pressure.
By the late 20th century, with rapid economic development, the dietary structure of Chinese residents improved significantly, leading to an increase in so-called “diseases of affluence.” Pu'er tea rose in popularity at this time, partly due to its ability to aid digestion and cut through greasy foods.
However, although these historical accounts contain numerous assertions about Pu'er tea's functions, they lack empirical evidence, classifying them as “experiential science,” which requires validation by “experimental science.” The key difference between experience and experiment lies in the reliance on data models versus individual perception. Rational experiments build upon sensory experiences, often corroborating each other and leading to similar conclusions.
Pu'er tea is no exception. With advances in biotechnology, scientific understanding of its functions has deepened, revealing phytonutrients—primary and secondary metabolites—that combat aging and prolong life.
Phytonutrients and Secondary Metabolites
Nutrients found in food are collectively known as nutrients. Essential nutrients for sustaining human life include water, carbohydrates, lipids, proteins, minerals, trace elements, vitamins, and dietary fiber. [1] Many plants also contain unique phytonutrients, such as allicin in garlic, lycopene in tomatoes, cordycepin in Cordyceps militaris, polyphenols and saponins in tea, etc. [2]
These phytonutrients are primary metabolites, with varying effects but all beneficial to human health. Some scholars regard them as precious natural substances, even referring to them as “plant gold.”
Pu'er tea contains the widest variety and highest concentration of phytonutrients among teas. Some may dismiss this claim as exaggeration or self-promotion, but we can verify it using tea polyphenols as an example.
Tea polyphenols (TP, Tea Polyphenols) are one of the most well-known phytonutrients in tea. Scientists classify them based on chemical structure, including L-EGCG, catechins, anthocyanins, etc. [3] First, L-EGCG is the only anticancer substance mentioned in the textbook “Chemistry of Tea.” From initial studies on antioxidant properties to recent discoveries of preventive effects against major diseases, L-EGCG is highly significant. [4] Catechins, a large family of compounds, are considered the most effective bioactive components in tea, with functions such as preventing vascular hardening, lowering cholesterol, anti-inflammatory, antibacterial, radiation protection, and anticancer effects. [5] Anthocyanins are water-soluble natural pigments with antioxidant, antiradiation, and ultraviolet resistance properties. They are now stably extracted and widely used in health supplements and cosmetics. [6]
In addition to these, there are nearly thirty types of amino acids, several dozen alkaloids, and beneficial substances like tea polysaccharides, γ-aminobutyric acid (GABA), theaflavins, and theanine in tea.
Pu'er tea is made from large-leafed varieties, with large leaves and thick spongy tissues containing up to one-third of tea polyphenolic compounds, the highest among all tea types. [7]
When drinking other types of tea, absorbing these phytonutrients presents a significant challenge: lipophilic phytonutrients are not water-soluble and are difficult to extract during regular brewing. However, Pu'er tea does not face this issue due to its processing technique, which involves kneading and sun-drying. This process converts many lipophilic substances into water-soluble forms, making the tea more durable and easier to absorb. Therefore, thanks to the combination of large-leafed varieties and unique processing techniques, Pu'er tea has the highest content of phytonutrients, which cannot be synthesized by the human body, improving our immunity and enhancing physical fitness.
Regarding specific categories, raw Pu'er tea contains the most phytonutrients, followed by ripe Pu'er tea, and least in aged Pu'er tea. However, in terms of another important substance—the secondary metabolites—aged Pu'er tea has the highest content.
Secondary Metabolites
In unfermented tea, most phytonutrients are primary metabolites. During Fermentation, these primary metabolites transform, degrade, and condense into characteristic secondary metabolites. [8] Secondary metabolites form a large family with over two thousand members, and there are still many undiscovered and unexplored varieties. These small molecules have very low molecular weights but strong activity, often attaching to larger polymers and providing numerous benefits to the human body. [9]
The currently discovered functions of secondary metabolites include activating the lymphatic system, enhancing the immune system, controlling cholesterol, regulating hematopoietic function, modulating the central nervous system and peripheral nerves, and reducing Hypertension. [10]
Pu'er tea, with its focus on post-aging, is rich in these secondary metabolites. The microbial fermentation of ripe Pu'er tea and the natural fermentation of raw Pu'er tea generate countless secondary metabolites. This is because Pu'er tea undergoes anaerobic fermentation, during which its color changes, and its phytonutrients transition from primary to secondary metabolites.
The transformation of tea polyphenols serves as a representative example. Research shows that the tea polyphenol content in fresh Pu'er tea is typically above 25%, while after fifty years of aging, the content drops below 5%. [11] These tea polyphenols do not disappear but transform into more valuable bioactive components, such as GABA with blood pressure-lowering effects and theaflavin groups with anticancer properties.
γ-Aminobutyric acid (γ-aminobutyric acid, abbreviated GABA) is an effective blood pressure-lowering component. It acts on the vas