How Many Times Should Tea Be Brewed for Health? Drinking Tea Incorrectly Can Cause Cancer
Wang Xingguo, Director of the Nutrition Department at Dalian Central Hospital, answers: Tea drinkers can easily feel the effect of tea on the gastrointestinal tract: they get hungry faster. This is because tea contains complex components such as caffeine, theophylline, and theobromine, which significantly stimulate gastric acid secretion and promote gastrointestinal motility. Increased gastric acid secretion (and accelerated gastrointestinal peristalsis) aids in food digestion, creating a sensation of reducing greasiness or feeling hungry more quickly.
However, do not mistake "reducing greasiness" or "hunger" for weight loss, because drinking tea only alters the process and sensation of digestion, not the outcome. The energy you consume from three meals a day—whether carbohydrates, proteins, or fats—will not disappear because of drinking tea. Clearly, drinking tea does not change your food intake or the composition of your feces; it only changes the digestive process from food to feces. How could this lead to weight loss?
Pu-erh tea and black tea stimulate gastric acid secretion more strongly than green tea, so drinking Pu-erh tea makes you feel hungry more easily. I have seen people endure stomach pain (related to increased gastric acid secretion damaging the gastric mucosa) while drinking Pu-erh tea for weight loss. Others attempt to infer tea's weight-loss effects from caffeine's stimulant properties. Caffeine increases alertness and basal metabolic energy expenditure, thereby aiding weight loss. While caffeine does boost energy and enhance athletic performance, its impact on basal metabolism is minimal. Therefore, tea, coffee, and caffeinated beverages are insufficient for achieving weight loss.
Unfinished Tea Most Easily Forms Tea Scale
Scientific research indicates that drinking water contains minerals and trace amounts of harmful heavy metal ions, such as cadmium, mercury, and arsenic. When water is heated, the solubility of certain calcium and magnesium ions decreases as the temperature rises, and the concentration of insoluble salts continuously increases. When the water is concentrated to a certain extent, precipitates form. These precipitates can enter the teacup when brewing tea. Tea that is not finished or left exposed to the air for an extended period undergoes oxidation between the tea polyphenols in the tea leaves and the metal elements in the tea scale, producing brown tea stains, commonly known as tea scale, which adhere to the inner wall of the cup. Tea scale contains various harmful metals like cadmium, lead, mercury, and arsenic, making it the primary culprit endangering human health.
Li Hongzhu, associate professor at the Tianjin Institute of Pharmaceutical Research, once stated in an interview: "Tea scale contains toxic substances such as cadmium, lead, mercury, arsenic, and carcinogens like nitrites. These substances adhere to the smooth surface of teacups. As tea is consumed, they enter the body's digestive system and combine with proteins, fatty acids, vitamins, and other nutrients in food, forming insoluble precipitates. This not only hinders the absorption and digestion of these nutrients but also damages organs like the stomach and intestines. Additionally, teacups that are not regularly cleaned accumulate more scale, which also contains large amounts of heavy metals, posing significant health risks." At the same time, these oxides entering the body can cause lesions and functional disorders in the nervous, digestive, urinary, and hematopoietic systems, and even lead to premature aging. In particular, arsenic and cadmium can cause cancer and fetal malformations, endangering health.
The thicker the tea scale, the harder it is to clean. Therefore, daily cleaning and regular deep cleaning are equally important. Experts recommend thoroughly washing tea ware after each use, even if no obvious tea stains are visible, to prevent accumulation.
(1) For stubborn, long-deposited tea scale, soaking it overnight with heated rice vinegar or baking soda, then scrubbing with a toothbrush, can easily clean it. Note: If using a purple clay teapot, avoid this method. Purple clay teapots have pores that can absorb minerals from tea scale, which helps maintain the pot and prevents harmful substances from leaching into the tea and being absorbed by the body.
(2) Place a small spoon of orange powder or orange juice in the teacup or teapot, fill with water, and let it sit for 2-3 hours. This loosens the adhesion between the tea scale and the tea ware, making it easier to remove.
(3) Add water and potato peels to the teapot or cup, bring to a boil, let it cool, and then rinse. This method easily cleans the scale.
(4) When using a metal tea strainer, it may turn black due to tea scale. If medium-strength cleaners don't work, soaking it in vinegar or bleach can easily remove the scale.
(5) Apply edible salt to the inner surface, especially on areas with tea scale. Then scrub the cup vigorously with a toothbrush and rinse thoroughly with clean water.
Experts particularly warn against using rough cleaning tools like steel wool or scrub balls to remove tea scale, as they can damage the glaze on the inner wall of tea ware, making it thinner over time. This allows future tea scale to penetrate deeply into the tea ware, making it extremely difficult to remove completely. It is advisable to use soft-bristled brushes, toothbrushes, or gentle cleaning cloths for washing.