Eight rumors about tea and food incompatibility, are they really like this?

As the saying goes, "after meals", "firewood, rice, oil, salt, sauce, vinegar and tea", tea has always been indispensable in the lives of ordinary people. Tea can cultivate one's character and improve one's sentiments; tea can refresh one's mind and eliminate boredom; tea can also speed up the body's metabolism and help prevent obesity and stones. However, in the daily process of drinking tea, there are still some aspects that are often overlooked and deserve our attention.

Myth: The sweetness of tea comes from the bitterness of life.

Rumor: The “sweet aftertaste” when drinking tea is because the bitter substances numb our perception of bitterness, which in turn promotes our perception of the sweet aftertaste.

The truth: The reason tea has a sweet aftertaste is because it contains sugar or amino acids. However, the tongue is more sensitive to bitterness, so it tastes the bitter substance first and then the sweetness.

Argument: "After bitterness comes sweetness" is a household idiom, which seems to suggest that sweetness comes from bitterness, but this may not be the case.

Generally speaking, when we drink tea, the first thing we feel is bitterness. That's because of the presence of substances such as theanine and tea polyphenols. So, do these bitter substances numb our sense of bitterness and thus prompt us to feel sweetness? (This is our common understanding) Wait a minute! Try taking a bitter pill such as quinine, and you will find that there will always be only bitterness in your mouth.

In fact, tea soup itself contains sweet substances, namely sugar and amino acids. It’s just that our tongue is more sensitive to bitterness, so the first things we taste are theanine and tea polyphenols. Only then did I taste the sweetness. This is the real source of the sweet aftertaste.

In addition, drinking tea also has the effect of promoting salivation, which simply means increasing the flow rate of saliva.

In addition to bitterness, tea polyphenols also have a special astringent taste. A group of proline-rich proteins (PRPs) are found in human saliva. These proteins have moisturizing and lubricating effects, but tea polyphenols can change their properties and form complexes, which make the oral epidermis feel that the lubrication disappears, which is the astringent taste.

This astringent taste, like the sour taste, can promote the flow of saliva, thus making us feel "saliva production".

The truth: Taking medicine with tea water will neutralize the effect of the medicine

Rumor: Don’t take medicine with tea, as it will neutralize the medicine’s effectiveness and will not effectively treat the disease.

The truth: The polyphenols and tannins in tea may form precipitation with the ingredients in the medicine and reduce its efficacy. Medicines should be taken with warm water.

Argumentation: In most cases, it is not recommended to take medicine with tea, especially western medicines containing iron such as ferrous sulfate, ferrous carbonate, citric acid, ferric amine and aluminum such as aluminum hydroxide. The metal ions in these medicines will combine with tea polyphenols in the tea soup and precipitate, thereby reducing or losing their efficacy.

Some Chinese herbal medicines, such as ephedra, coptis chinensis, diaotenghoo, scutellaria baicalensis, ginseng and corresponding biological alkali preparations, as well as drugs such as atropine and aspirin, are generally not suitable for mixing with tea, otherwise the active ingredients of Chinese medicine such as ephedrine will be precipitated by the tannic acid in the tea and lose their efficacy.

It is not advisable to drink tea when taking enzyme preparations such as protease and amylase. The polyphenols in tea can combine with enzymes and reduce the activity of the enzymes. In addition, tea contains caffeine (also known as "caffeine"), which has a stimulant effect. Therefore, when taking sedatives, hypnotics, and antitussive drugs, it is not advisable to take them with tea to avoid drug conflicts and reduce the efficacy of the drugs.

Myth: Drinking overnight tea can cause cancer

Myth: Tea is a very healthy drink. But people often say: "Overnight tea is as poisonous as a snake", so many people choose to drink freshly brewed tea and pour out the tea brewed the day before. Recently, a netizen posted a message saying: "Tea will go bad if left for a long time, and it can also produce a large amount of nitrite, which is harmful to the human body, so overnight tea should not be drunk." Is overnight tea really harmful to the human body?

The truth: The main change in overnight tea is that tea polyphenols are oxidized to form more pigments, so the tea soup looks darker. At the same time, some flavor substances, such as amino acids, are oxidized and lose their umami taste. If there is no foreign microbial contamination, it is safe.

Argument: The CCTV program "Is It True?" investigated this statement and concluded that overnight tea is safe and drinkable.

First, verify the truth through experiments. CCTV reporters selected three types of tea that people commonly drink: Longjing, Pu'er and chrysanthemum tea. At 9 a.m. on the first day of the experiment, the reporter brewed the three types of tea and left the tea to stand. At 9 o'clock that evening, the reporter also brewed three cups of tea and set them aside. At 9 am the next day, the reporter brewed three new cups of tea. At this time, the tea brewed at 9 o'clock in the morning of the previous day has been brewed for 24 hours, and the tea brewed at 9 o'clock in the evening of the previous day has been brewed for more than 12 hours. After being left out for a long time, how different are these overnight teas from freshly brewed teas?

The truth team invited national senior tea taster Lou Guozhu to conduct a professional evaluation of the taste of these overnight teas. Mr. Lou compared the taste and flavor and determined that the overnight tea had not deteriorated whether it was left for 12 hours or 24 hours. "Although it has been brewed for a long time, it still has the taste that the tea should have. Pu'er tea is about presentation and mellowness, and overnight tea may be even better."

Lou Guozhu, a national senior tea taster, said: "If a cup of boiled water and a cup of tea are left overnight, the nitrite content in the tea is less than that in the boiled water. This is because tea contains a relatively high content of tea polyphenols, as well as some vitamin-like substances, which play a role in inhibiting the formation of nitrite and are a natural antioxidant."

Overnight tea: It has been proven that it is safe and drinkable. As for how to drink tea in a healthier way, experts suggest: "Drinking tea on an empty stomach can cause great irritation to the stomach. You should avoid drinking overnight herbal tea on an empty stomach. Adding a little warm water or warm tea to it is still good for the human body."

Truth: Drinking tea can reduce mortality

Rumor: Professor Nicolas Danchin from France announced a study involving 131,000 people at the European Society of Cardiology annual meeting on August 31. The study revealed that drinking tea can reduce non-cardiovascular mortality by 24%.

The truth: The survey results show that coffee drinkers are more likely to suffer from cardiovascular disease than tea drinkers, while tea drinkers are in relatively better physical condition. The main reason is that tea contains antioxidant ingredients such as flavonoids, which help prevent cardiovascular diseases.

Argument: Coffee and tea are both important parts of our lives. Their effects on cardiovascular (CV) health have been studied in the past, with sometimes conflicting results.

Professor Tang Shan's research subjects were 131,401 people aged 18 to 95, all of whom had undergone physical examinations at the Center for Preventive Medicine of the Free School of Philosophy and Psychology in Paris between January 2001 and December 2008. Over a median of 3.5 years, there were 95 cardiovascular deaths and 632 non-cardiovascular deaths. Coffee or tea consumption was categorized into three levels on a self-administered questionnaire: none, 1–4 cups per day, and more than 4 cups per day.

Researchers found that coffee drinkers have a higher risk of cardiovascular disease than non-drinkers, especially smokers. Among non-drinkers, 17% were current smokers, compared with 31% and 57% of those who drank 1-4 drinks per day and 4 or more drinks per day, respectively.

Non-coffee drinkers were more physically active, with 45% reporting high levels of physical activity compared to just 41% of heavy coffee drinkers. Professor Tang Shan said: "This is a significant gap in our huge sample population."

Heavy coffee drinkers were older than non-drinkers, with the former averaging 44 years old and the latter averaging 40 years old. The differences in blood pressure were smaller, with heavy coffee drinkers having slightly lower systolic blood pressure and slightly higher diastolic blood pressure after adjusting for age.

The risk factor for tea drinkers is exactly the opposite of that for coffee drinkers, with drinkers having a lower risk of cardiovascular disease than non-drinkers. One-third (34%) of non-drinkers are current smokers, compared with 24% and 29% of those who drink 1 to 4 drinks a day and 4 or more drinks a day, respectively. Physical activity also increased with the number of cups of tea consumed per day, from 43% among moderate drinkers to 46% among heavy drinkers.

Tea has a more significant effect on blood pressure than coffee. After adjustment for age, heavy tea drinkers have a 4-5 mmHg lower systolic blood pressure and a 3 mmHg lower diastolic blood pressure than non-drinkers.

Coffee tended to increase cardiovascular mortality in heavy drinkers compared with non-drinkers, but the effect was not significant. Coffee consumption significantly increased non-cardiovascular mortality, but this effect disappeared after adjustment for smoking behavior. Professor Tangshan said: "The tendency of coffee drinkers to have a higher mortality rate may be largely explained by the fact that there are more smokers among people who drink a lot of coffee."

Tea drinking tends to reduce cardiovascular mortality, but the effect is not significant after adjustment for age, gender, and smoking behavior. However, tea consumption significantly reduced the risk of non-cardiovascular death, with a risk ratio of 0.76 for tea drinkers compared with non-drinkers.

He concluded: "The antioxidants in tea may provide a survival benefit. Tea drinkers also have healthier lifestyles, so whether tea drinking reflects some personal trait or tea itself produces better results is, in my opinion, an open question. Leaving that question aside, I think you could quite sincerely recommend tea over coffee."

Tea and sugar

Rumor: Tea tastes bitter and cold in nature. People drink tea to stimulate the digestive glands with the help of the bitterness of tea, promote the secretion of digestive juices, and enhance digestive function. If sugar is added to tea, this function will be inhibited.

Detoxification: The effects of "enhancing digestion, clearing away heat and detoxifying" are effective precipitates in tea, such as theanine and tea polyphenols. Some of these precipitates will taste bitter, but it is not the taste that is effective but the substance that presents the taste. White sugar does not

It can chemically react with the precipitable substances in the tea leaves, causing them to become ineffective. At most, it can increase the heat of the tea and destroy the original flavor of the tea. Traditional Chinese medicine also uses honey to neutralize the bitterness of medicinal materials.

Tea and eggs

Rumor: The tannic acid in tea can turn the protein in food into a coagulated substance that is difficult to digest, affecting the body's absorption and utilization of protein.

Detoxification: There is actually no evidence that tea eggs are more difficult to digest than simply boiled eggs. The coagulation of egg protein is caused by heating and cooking. Adding tea leaves or not does not affect the coagulation of eggs. The human body has no problem absorbing denatured proteins, such as cooked meat, eggs, and tofu solidified from soy milk.

In fact, when cooking tea eggs, the antioxidants such as tea polyphenols in the tea can prevent the cholesterol in the eggs from being oxidized, and instead protect the nutrients in the tea. Foodies who like to eat tea eggs can rest assured.

Tea and Lamb

Rumor has it that when eating mutton and drinking tea, the rich protein in the mutton can "marry" with the tannic acid in the tea to produce a substance called tannic acid protein. This substance has a certain astringent effect on the intestines, which can weaken intestinal peristalsis, reduce the water content in the stool, and make constipation more likely to occur.

Detoxification: Nomadic people often drink tea while eating beef and mutton, and they do not suffer from constipation. In fact, drinking tea has the effect of promoting digestion and defecation, and "detoxifying cattle and sheep." The tea polyphenols in tea do not actually have the same strong protein coagulation ability as tannic acid, and calling it "tannic acid" itself is an unprofessional term.

Tea with milk

Rumor: The oxalic acid in tea will react with the calcium in milk to form calcium oxalate, which not only reduces the body's absorption of calcium but is also toxic to the body.

Detoxification: The oxalic acid content in tea is not high. The oxalic acid contained in 10g of tea will roughly cause the human body to absorb 5mg of calcium - this is equivalent to the calcium content in 5g of milk. We can still afford to lose such a small amount of calcium o(╯□╰)o The human body cannot absorb calcium oxalate, so it will isolate the harm of oxalic acid to the human body. Why not? For those who like to drink milk tea, go ahead and eat it ^_^