The 6 most worrying questions for coffee fans! The benefits and disadvantages of coffee!

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With the annual growth of coffee consumption in China, drinking coffee has gradually become the beginning of a busy day for some modern people every morning. However, the per capita coffee consumption of Chinese mainland is only six cups a year, which is a far cry from that of Taiwan compatriots across the sea, not to mention South Korea, Japan and other countries. In the final analysis, apart from the fact that the food culture is difficult to reverse in a short period of time, lack of understanding and even misunderstandings about things like "coffee" is also one of the obstacles to the growth of coffee consumption.

Today, the editor answers the six questions that coffee fans are most worried about.

Q: why is drinking coffee refreshing?

Everyone knows that caffeine (Caffeine) in coffee can be refreshing and exhilarating, but have you ever wondered why a small cup of coffee can provide so much energy? It starts with why people want to sleep.

Adenosine (Adenosine) is a substance that inhibits nerve conduction and makes people want to sleep when it starts to release. The chemical structure of caffeine happens to be similar to that of adenosine. If we consume caffeine, the receiver in our body will receive refreshing caffeine instead of stimulating adenosine. In particular, when adenosine is blocked, it signals the adrenal gland to produce adrenaline; at the same time, stimulants such as dopamine become more active, and when these mechanisms work at the same time, the body is in a "party" state. So it's not caffeine that provides energy, it changes nerve conduction.

If you want to refresh yourself, you must drink coffee before you feel tired and let the caffeine go to the card early in order to play a brain-awakening effect. However, there are also people who fall asleep after drinking coffee, which may be due to genetic differences that make the receiver in the body insensitive to caffeine and adenosine will not be replaced, thus unable to perform the refreshing function.

Q: will drinking coffee lead to osteoporosis?

It is rumored that oxalic acid and caffeine in coffee can affect calcium absorption, but from a scientific point of view, the content of oxalic acid in coffee is very low, even lower than the usual Chinese cabbage, with only 0.9 milligrams of oxalic acid per 100 grams of coffee; no studies have confirmed that caffeine affects vitamin D, which absorbs calcium.

It is worth noting, however, that caffeine may release bone calcium into blood calcium. But the study also points out that if people get enough calcium, they can offset this situation, which means that the key to osteoporosis is the usual lack of calcium intake. Therefore, it is recommended that in addition to increasing calcium intake from the daily diet, you can also choose to add milk flavor when buying coffee, so that you can also supplement calcium while drinking coffee.

Q: what kind of teeth will turn yellow when drinking coffee?

When the tooth enamel is cracked, it is easy to let the coffee pigment adhere to the surface of the tooth. And drinking coffee reduces the secretion of saliva, which is an important substance to prevent tooth decay, so coffee itself may also make teeth lose their protective layer and become yellow more easily. However, because the coffee pigment belongs to exogenous staining, you can use straws when drinking, gargle with boiled water after drinking coffee, and brush your teeth to reduce the effect of pigment on teeth in a short time.

Q: how many cups of coffee can I drink a day?

According to the US Dietary guidelines for 2015-2020, caffeine intake is recommended to be less than 400mg. Take convenience store coffee as an example, the content of American caffeine in medium cup is between 100mg and 200mg, that is, the amount of caffeine that can be consumed in a day is within 2 to 4 cups. The amount of caffeine in each cup of coffee varies according to the way it is roasted and the time it takes to soak, so it is difficult to calculate the exact amount.

What needs to be particularly careful is that caffeinated drinks such as tea, cocoa, cola and energy drinks may also be consumed in daily life, which need to be counted.

Although studies have shown that coffee can help reduce the risk of cardiovascular and neurodegenerative diseases, it is not recommended for people with no drinking habits to start drinking coffee because of the divergent results of various studies and their applicability to each person. In addition, it should be noted that drinking coffee with cream or sugar may cause excess fat and sugar intake.

Q: coffee contains acrylamide. Do you need to worry about it?

In 1994, the World Health Organization's International Center for Research on Cancer (International Agency for Research on Cancer, referred to as IARC) classified acrylamide as a "carcinogen that may cause human cancer" (removed in 2016), and coffee is the food containing this substance, which has aroused public concern. In fact, apart from coffee, any starchy food containing asparagine and reducing sugar may produce acrylamide after baking or frying at more than 120 degrees Celsius. 7000 kinds of foods around the world, such as fried baked potato products, bread and even black sugar, are included.

At present, acrylamide has only been proved to be carcinogenic in animal experiments, but it has not been proved to be carcinogenic to humans, which can only be said to be "possible". According to the relevant "acrylamide index value in food" test shows that roasted coffee is 450 μ g / kg; instant coffee is 900 μ g / kg, while only California in the world has announced a daily intake limit of 140 μ g / kg bw, if the weight is 60 kg, it is possible to exceed the standard by eating 18.6kg roasted coffee or 9.3kg instant coffee, so we do not have to worry too much.

Q: can pregnant women drink coffee?

Studies have shown that excessive caffeine intake by pregnant women does increase the risk of miscarriage or sudden fetal death. And caffeine will enter the fetus through the placenta, which may make children prone to anxious symptoms, growth retardation, metabolic abnormalities, and affect the control of blood sugar and blood pressure in the future. However, it is rumored on the Internet that pregnant women drinking coffee can cause deformed children, which has not been confirmed by research.

According to the recommendations of the World Health Organization, pregnant women should not consume more than 300 milligrams of caffeine per day (about 1.5 cups of coffee in convenience stores). Although the strong taste of coffee can not stop, but the child's health is only once, it is recommended that mothers-to-be should avoid certain foods during pregnancy. As for the rumors that drinking coffee darkens the skin of the fetus, the color of the fetus is basically controlled by genes, and drinking coffee does not change the color of the skin.

An appropriate amount of coffee intake will do no harm to the human body, and all food is a gift from heaven. So the next time you taste a cup of coffee, in addition to allowing you to enjoy a leisurely and relaxed atmosphere to relieve stress, relax body and mind, and eliminate fatigue, this small cup of coffee is building a strong defense line for your health. Protect you carefully, just remember not to drink too much!

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