The gastrointestinal tract is the primary organ for digestion and absorption in the human body. Gastrointestinal diseases often prove difficult to treat due to an inability to pinpoint the cause, and most patients with such conditions require medication. However, frequent use of drugs can lead to dependency, irritate the gastrointestinal tract, and cause many adverse reactions. Therefore, daily regulation and prevention of gastrointestinal diseases are particularly important. Tea is a naturally occurring beverage that is loved by consumers for its many benefits, and its health functions have been a research hotspot both domestically and internationally over the past two decades. Among the numerous Health benefits attributed to Anhua dark tea, its ability to regulate gastrointestinal function has attracted considerable attention from researchers and consumers alike, with an increasing number of studies focusing on this health attribute.
I. Anti-diarrheal Effect
Studies show that water extracts of Fu brick tea can prevent and treat secretory Diarrhea caused by senna leaves, non-infectious exudative diarrhea caused by castor oil, and osmotic diarrhea caused by magnesium sulfate. The anti-diarrheal effect of aged Fu brick tea is even better, and there is a dose-response relationship. Research also found that Fu brick tea not only treats diarrhea in mice but also has a preventive effect, significantly inhibiting the occurrence of loose stools.
Using senna leaves to establish a mouse model of diarrhea, the effects of water-soluble extracts of Fu brick tea on the counts of Escherichia coli, enterococci, bifidobacteria, and lactobacilli in the intestines, as well as the condition of the intestines, were measured. Results showed that high and medium doses of Fu brick tea promote the growth of beneficial microorganisms in the gut while inhibiting the proliferation of harmful microorganisms, effectively countering the disruption of intestinal microflora caused by senna leaves. The most significant effect was observed on lactobacillus proliferation, with all preventive groups promoting lactobacillus growth in a dose-dependent manner. High-dose treatment groups could also promote lactobacillus proliferation, even more so than the positive drug berberine. Medium and low doses reduced the numbers of enterococci. Fu brick tea can repair the intestinal structure of mice experiencing diarrhea caused by drugs, and the intestinal cavity condition of mice given the tea infusion is comparable to that of normal mice.
II. Laxative Effect
Through the small intestinal propulsion test in mice, it was discovered that water extracts of Fu brick tea have a certain promoting effect on the propulsion movement of the small intestine in normal mice. Different doses of Fu brick tea can counteract the inhibitory effect of atropine sulfate on small intestinal propulsion in mice, with the effect becoming more pronounced with higher doses. High doses of Fu brick tea can inhibit the hyperkinetic effect of methanesulfonamide neostigmine on small intestinal propulsion, indicating a bidirectional regulatory effect on small intestinal propulsion. The longer-stored Fu brick tea group had a higher propulsive rate in the normal mice's small intestinal charcoal propulsion test, showing a more significant promotion effect.
Water extracts and whole powder of golden Flower dark tea have the effect of enhancing small intestinal motility, shortening defecation time, and increasing defecation volume in mice with inhibited small intestinal motility caused by loperamide, with a dose-response relationship.
Different doses and types of tea preparations affect the small intestinal motility (ink propulsion rate) of mice:
Gavage with high doses of Qianliang tea, Fu brick tea, and other dark teas can effectively reduce the residual rate of stomach contents in mice, promote gastric emptying, and significantly enhance small intestinal motility, increasing small intestinal propulsion function. Both the high and medium dose groups of dark tea can change the number of intestinal flora in a direction beneficial to human health, although the effect of the low dose group is not significant.
III. Regulating Intestinal Microbiota and Promoting Health
1. Regulating Intestinal Immunity
After administering water extracts of Fu brick tea to mice with dysbiosis of intestinal flora, the intestinal flora of each group of mice was adjusted, and the levels of small intestinal mucosal sIgA, serum IL-2, serum albumin, and total protein increased, showing significant differences compared to the natural recovery group. The high-dose group was more effective than the low-dose group, clearly demonstrating that water extracts of Fu brick tea can repair damaged mucosa and have the function of regulating intestinal immunity.
2. Defending Against Non-alcoholic Fatty Liver Disease (NAFLD)
By studying the inhibitory effect of Fu brick tea on the infiltration of inflammatory cells in the jejunum and colon of rats with non-alcoholic fatty liver disease (NAFLD), it was found that Fu brick tea can reduce the shedding, breakage, sparseness, and disarray of villi in the jejunum, increase the villus height-to-crypt depth ratio in the jejunum, decrease the number of intraepithelial lymphocytes in the jejunum, and increase the number of goblet cells in the jejunum and colon. This indicates that Fu brick tea can effectively improve the intestinal mucosal barrier damaged by a high-fat diet, playing a role in preventing and treating NAFLD.
Histological sections of rat intestines (JE-jejunum, CO-colon; A-normal group, B-NAFLD group, C-low dose Fu brick tea group, D-high dose Fu brick tea group. Compared to the normal group, the NAFLD group shows a large number of broken villi in the jejunum, disordered arrangement, and obvious shedding from the intestinal mucosa. There is infiltration of inflammatory cells indicated by black arrows in the jejunum and colon. This suggests that a high-fat diet disrupts the integrity of the rat's intestinal morphology and increases inflammation. Compared to the NAFLD group, the villi in the jejunum of the Fu brick tea group are neatly arranged, compact, and highly intact, with no inflammation or pathological characteristics in the jejunum and colon. This suggests that Fu brick tea can protect the integrity of the intestinal morphology of NAFLD rats and alleviate intestinal inflammation.)
3. Repairing Intestinal Inflammation
The study evaluated the preventive and protective effects of water extracts of Fu brick tea, alcohol-soluble extracts enriched with Fu brick tea polyphenols, and alcohol-sediment extracts enriched with Fu brick tea polysaccharides on dextran sulfate sodium-induced inflammatory bowel disease in mice, as well as their effects on oxidative stress and inflammatory factors in mice with inflammatory bowel disease. It was found that all three extracts could reduce cytokine levels, effectively alleviating the systemic inflammation level in inflammatory bowel disease, and had a certain preventive and protective effect against dextran sulfate sodium-induced inflammatory bowel disease.
4. Improving Lipid Metabolism
Research shows that water extracts of Fu brick tea can regulate the structure and function of the intestinal microbiome, affecting the enterohepatic bile acid metabolism cycle, enhancing the body's Antioxidant activity, and increasing systemic lipid consumption, which has a clear protective effect on the structure and function of the liver and intestines, improving lipid and inflammatory responses, and inhibiting excessive weight gain in rats fed a high-fat diet.
Mechanism of Fu brick tea water extract in preventing obesity and hypercholesterolemia
5. Inhibiting Pathogenic Gut Bacteria
Dysbiosis of the gut microbiota is a critical factor in the development of alcoholic fatty liver disease (AFLD). Anhua dark tea can significantly prevent chronic alcohol exposure-induced hepatic steatosis in mice, reduce oxidative stress and inflammation, and regulate the gut microbiota. Dark tea can prevent AFLD caused by chronic alcohol exposure by regulating the gut microbiota. Fu brick tea significantly restores the elevated Firmicutes/Bacteroidetes ratio. It induces an increase in the abundance of beneficial bacteria such as Clostridi