These foods secretly contain caffeine and may keep you from sleeping well all night!

Have you ever had this experience: you didn’t drink coffee, but you still couldn’t fall asleep, tossing and turning, with all kinds of thoughts flashing through your mind?

In fact, there may be a "black hand" behind this - caffeine. Yes, you heard it right, in addition to coffee, many foods contain caffeine, the "sleep thief".

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These foods are secretly containing caffeine

"Dietary Caffeine Intake Levels and Risk Assessment of Chinese Residents" introduces that the main source of caffeine for Chinese residents is beverages.

Since my country has a habit of drinking tea, for adults, the biggest sources of caffeine are tea leaves, tea drinks, milk tea and coffee. Tea is the biggest source of caffeine, contributing 74.80% of caffeine intake, much more than any other food; while for minors, caffeine mainly comes from milk tea, tea drinks, tea leaves and chocolate.

However, the types of foods that contain caffeine are not just coffee and tea. If you keep reading, you may be surprised to find that these foods are also frequent visitors of caffeine.

1. Coffee

Coffee is a well-known beverage that contains caffeine. The caffeine content of each cup of coffee may vary depending on the type and concentration, but it is usually between 80 and 180 mg. The caffeine content of different brands varies greatly. For example, the caffeine content of several classic coffees (medium cup Grande) from Starbucks is as follows↓

Some people may see the word "decaffeinated coffee" on coffee and think that it really does not contain caffeine. In fact, this is because some special methods or special coffee beans are used to reduce the caffeine in the coffee.

This type of coffee contains less caffeine than regular coffee, but it still has some caffeine. For example, a 236mL cup of decaffeinated coffee usually contains 2 to 15 mg of caffeine. So if you are particularly sensitive to caffeine, it is best not to drink it at all.

2. Various tea-containing drinks or foods

Many health-conscious and middle-aged people like to drink tea, while young people prefer milk tea and fruit tea. No matter which kind, as long as it contains tea, there will be caffeine. The caffeine content is related to the type of tea and the amount of tea used.

Tea

Generally speaking, the caffeine content of a cup of tea may be between 20 and 100 mg. The stronger the tea, the higher the caffeine content. Black tea of ​​equal concentration has more caffeine than green tea, and brewed tea has more caffeine than bottled tea beverages.

Data source: Mayo Clinic

●Milk tea, fruit tea, etc.

The caffeine content of a cup of milk tea is between 50 and 150 mg, and some brands may be above 200 mg. So people often say, why do I suffer from insomnia after drinking a cup of milk tea? The reason is self-evident...

Image source: Shenzhen Guangming District Consumer Council Pearl Milk Tea Comparative Test

Compared with milk tea, the caffeine content of fruit tea is much lower. If you are sensitive to caffeine but want to drink a happy drink, fruit tea without the tea base is a good choice.

●Matcha and its products

In addition to the above tea drinks, matcha is also a tea product that is easily overlooked.

According to the data from the "Japanese Food Standard Composition Table" of the Ministry of Education, Culture, Sports, Science and Technology of Japan, each gram of matcha powder contains 32 mg of caffeine.

Image source: "Japanese Food Standard Composition Table"

In the ingredients for making matcha drinks on a certain recipe app, the amount of matcha powder used ranges from 2g to 10g, which means that a cup of matcha drink contributes 63 to 320mg of caffeine.

Image source: Xiachufang

In addition to making drinks, you also need to be careful when using matcha pudding, cakes, biscuits, bread, ice cream, etc.

3.Cola and functional drinks

Cola and energy drinks (such as Red Bull) also contain caffeine. Generally speaking, every 100mL of cola contains about 10mg of caffeine, for example, a common bottle of 500mL cola contains about 50mg of caffeine.

The caffeine content of functional drinks varies greatly between brands. According to the random inspection by the Shenzhen Consumer Council, the caffeine content of each can of functional drinks of different brands ranges from 10 to 100 mg, with most of them being around 50 mg, which is equivalent to the content of a bottle of cola.

Image source: Shenzhen Consumer Council randomly inspected 10 functional beverages

4. Chocolate and its products

Chocolate, whether dark or milk, contains caffeine because cocoa powder itself is a natural ingredient that contains caffeine. Generally speaking, the purer the chocolate, the higher the caffeine content.

According to the United States Department of Agriculture (USDA), the caffeine content of chocolate with different cocoa solids ratios is as follows:

Biscuits, cakes, candies, ice cream and other foods made with chocolate or cocoa powder also contain caffeine. So next time when you choose snacks for your children, pay attention to the ingredients of the food!

5. Supplements and medicines

Seeing this, you may be surprised, why is caffeine added to medicines and health products?

Yes, some cold medicines also add caffeine to relieve pain and reduce fatigue, and some foreign nutritional supplements also contain caffeine.

Image source: A certain brand of cold medicine

Not everyone can handle caffeine

These friends should pay attention

1. Different people have different safe daily caffeine intakes

Healthy adults

For healthy adults, the consensus reached by international authoritative organizations is that daily caffeine intake below 400 mg will not have adverse effects on health. If converted into coffee, it is equivalent to controlling the intake within 2 cups per day.

However, for people in special physiological stages, such as pregnant women, breastfeeding mothers, and children and adolescents in the growth and development stage, there are different standards for caffeine intake.

Pregnant women

Although the American College of Obstetricians and Gynecologists (ACOG) believes that no more than 200 mg of caffeine per day is safe during pregnancy and lactation, the Chinese Nutrition Society does not recommend pregnant women to drink caffeinated beverages such as coffee in the "Dietary Guidelines for Chinese Residents (2022 Edition)". If you drink, do not drink more than 1 cup.

Image source: "Dietary Guidelines for Chinese Residents (2022 Edition)"

●Breastfeeding women

For breastfeeding mothers, especially within 3 months after giving birth, it is not recommended to drink caffeinated beverages because babies within 3 months of birth cannot metabolize caffeine.

Although it can be gradually metabolized after 3 months, the caffeine in breast milk can cause irritability in babies and affect their sleep quality. Long-term intake can affect the development of the baby's nervous system. Therefore, if you want to drink after 3 months of giving birth, do not exceed 1 cup of coffee or milk tea.

Image source: "Dietary Guidelines for Chinese Residents (2022 Edition)"

Children and adolescents

Regarding children and adolescents in the growth and development stage, the international consensus is that it is not recommended to drink it. However, when it comes to specific ages, the recommendations of different organizations are not consistent.

The American Academy of Pediatrics: Avoid giving caffeinated foods to babies under 12 years old.

European Food Safety Authority: For children aged 3 to 10, the safe amount of caffeine per day is 0.2 to 2 mg/kg of body weight; for children aged 10 to 18, the safe amount per day is 0.4 to 1.4 mg/kg of body weight.

"Australian Healthy Eating Guidelines": Children under 15 years old are not recommended to drink coffee, and other caffeinated foods such as milk tea, dark chocolate, strong tea, etc. should not be provided.

"Dietary Caffeine Intake Levels and Risk Assessment of Chinese Residents": The safe caffeine intake for minors under the age of 18 is 2.5 mg/kg body weight.

In general, stay away from it if you are under 12 years old, and consume less after that.

2. These types of people are sensitive to caffeine, so be careful!

Symptoms of caffeine overdose may vary from person to person, but common manifestations include anxiety, irritability, insomnia, palpitations, stomach discomfort, nausea, vomiting, tremors, polyuria, etc. If one or more of these symptoms occur, it may indicate that the amount of caffeine you have consumed has exceeded the safe range.

Except for pregnant women, nursing mothers and minors, friends with heart disease, high blood pressure and sleep disorders should avoid drinking to avoid aggravating their condition.

Since caffeine increases calcium loss, older people should try to control their caffeine intake to avoid increasing the risk of osteoporosis.

Friends who are particularly sensitive to caffeine also need to pay special attention and try to reduce their daily caffeine intake to a minimum.

Healthy caffeine intake

Pay attention to these points

To understand this question, we need to first understand how caffeine helps us stay awake.

1. The principle of coffee refreshing

Image source: foodrepublic

Simply put, adenosine in the brain is a chemical that promotes sleep. When it binds to receptors, it makes people feel sleepy and tired. The metabolites of caffeine compete with adenosine and occupy these receptors, thereby preventing adenosine from binding to receptors and keeping people awake and alert.

2. The best time to drink coffee

●Before drowsiness: 0.5 to 1 hour

You can observe the time when you feel sleepy every day. For example, if you start to feel sleepy around 2 pm, you can drink coffee between 1 pm and 1:30 pm. This time period is most effective.

This is because it takes about 45 minutes for 99% of caffeine to enter the body and take effect. So it is very important to grasp the timing.

●After feeling sleepy: drink coffee and take a 20-minute nap

You may say, sometimes I forget to drink and feel sleepy, is there any remedy?

Although adenosine has already bound to the receptor when you feel sleepy, a short nap can remove the adenosine on the receptor. At this time, caffeine can take advantage of the opportunity to enter and take over the magpie's nest, giving the brain the illusion that "I am not sleepy anymore."

Summarize

Caffeine is widely found in beverages or foods such as tea, coffee, cola, functional drinks, cocoa, chocolate, etc. It may also be contained in some health products or medicines. For healthy adults, there is no need to worry if they drink less than 2 cups a day.

If you are sensitive to caffeine, it is best to drink less or not drink it. When buying medicines and health products, also pay attention to whether the ingredients contain caffeine.

References

[1] National Food Safety Risk Assessment Center. Dietary caffeine intake level and risk assessment of Chinese residents[R]. Beijing: National Food Safety Risk Assessment Center, 2021.

[2] Yang Yuexin, Ge Keyou. Chinese Nutrition Science Encyclopedia 2nd Edition (Volume 2)[M]. People's Medical Publishing House, 2019.

[3] Chinese Nutrition Society. Dietary Guidelines for Chinese Residents[M]. People's Medical Publishing House. 2022.

[4] Ministry of Education, Culture, Sports, Science and Technology of Japan. Standard Composition Table of Japanese Foods

[5] United States Department of Agriculture. Food Database

[6] Mayo Clinic. Caffeine content in coffee, tea, carbonated drinks, etc. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20049372

[7]Starbucks official website. https://www.starbucks.com/menu/drinks/hot-drinks

[8] Coca-Cola official website. https://www.coca-colacompany.com/about-us/faq/what-is-caffeine

[9]FDA.SpillingtheBeans:HowMuchCaffeineisTooMuch?[10]KoleJ,BarnhillA.CaffeineContentLabeling:AMissedOpportunityforPromotingPersonalandPublicHealth.JCaffeineRes.2013Sep;3(3):108-113.doi:10.1089/jcr.2013 .0017.PMID:24761278;PMCID:PMC3777296.[11]SamiG.Alsabri,WalidO.Mari,SaraYounes,MuradA.Elsadawi,andTerryL.Oroszi.KineticandDynamicDescriptionofCaffeine.JournalofCaffeineandAdenosineResearch.Mar2018,p3-9.

Planning and production

This article is a work of Science Popularization China-Starry Sky Project

Produced by: Science Popularization Department of China Association for Science and Technology

Producer｜China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.

Author: Li Chun, National Registered Nutritionist

Review | Zhong Kai, Researcher at the National Food Safety Risk Assessment Center