There are many reasons why people drink matcha tea, but it seems that the health benefits of this beverage may come with some side effects.
Matcha is a finely ground powder that is made from green tea leaves. When you drink matcha, you’re consuming all of the nutrients that are found in those leaves (including caffeine) and a powerful antioxidant called epigallocatechin gallate, or EGCG for short.
Matcha drinkers say that they feel more energized and focused after drinking it, which makes sense as both caffeine and EGCG have been linked to improved mental performance and mood. However, there’s one catch: matcha may also come with some unpleasant temporary side effects.
In this article, we’ll explore 9 side effects of matcha tea that you should be aware of. Before we proceed, let’s take a closer look at matcha tea benefits.
What are the benefits of matcha tea?
Matcha tea, a powdered green tea, originated in Japan, but its tea seeds were initially cultivated in China. It is a specific type of green tea subject to stringent growth and production standards. Made from the buds and top layers of shade-grown Camellia sinensis (C. sinensis) plants, matcha is consumed in various forms, including capsules, food bars, and reconstituted drinks.
Active Substances in Matcha Tea:
- Catechins, particularly EGCG
Rich in these active substances, matcha offers potential benefits, which is one of the reasons that have fuelled its cultural acceptance in recent years. However, despite its growing popularity, understanding the uses of matcha tea, its side effects, and interactions is crucial for informed consumption. (13)
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The most prominent benefits of matcha tea include:
- Antioxidant Power
Matcha’s catechins act as potent antioxidants, stabilizing free radicals, and mitigating cell damage. As they are cultivated in shaded areas, matcha yields three times more catechins, potentially reducing chronic disease risks.
- Improves Liver Health
Studies have suggested that matcha may contribute to liver health.
- Boosts Brain Function
Matcha components enhance brain function, with research showing improved attention, reaction time, and memory.
- Promotes Heart Health
Matcha’s nutrient profile, akin to green tea, hints at potential heart health benefits and is linked to lower cardiovascular disease risk.
- Weight Loss Support
Recognized for helping with weight loss, a 2020 review even suggested that up to 500 mg daily for 12 weeks could potentially reduce body mass index (BMI). In addition, matcha shares compounds with green tea, which makes it useful in weight management strategies. (1)
Despite the health benefits, overindulgence with matcha tea could have potential side effects. Our guide takes you through the different aspects.
Side Effects of Matcha Tea
Can Make You Feel Nervous and Anxious
It’s also worth noting that some people are more sensitive to caffeine than others. If you don’t have much experience with caffeinated products, it may be best to start by drinking a little bit of matcha and build up your tolerance gradually.
If the jitters are too strong for you, then you should consider trying decaffeinated matcha, which contains about 3 to 10 milligrams of caffeine per serving compared to a typical cup of brewed green tea that has approximately 40 milligrams.
May Mess with Your Sleep
Drinking caffeine at night is bad for your sleep and it’s best to avoid matcha before you go to bed.
Caffeine can stay in the body for several hours, so if you have a cup of matcha late in the afternoon or early evening, it may affect your ability to fall asleep later that night (7).
Can Cause Stomach Discomfort
The caffeine and fiber content of matcha can have a laxative effect for many people, particularly those who don’t usually drink caffeinated beverages or tea regularly (6).
As matcha is consumed in such large quantities relative to other teas, it’s not surprising that the laxative effect may be stronger than your normal serving of brewed green or black tea.
If you drink too much matcha in a short period, you may end up with an upset stomach. This is because caffeine stimulates the central nervous system and can lead to feelings of jitteriness and anxiety.
It can also irritate parts of your digestive tract by changing their shape or promoting muscle contractions, so if you have sensitive stomach tissue, you may want to give your gut a break from drinking too much green tea in general. EGCG can cause inflammation when it is consumed in high doses over long periods, so if you drink lots of matcha every day, it may exacerbate any pre-existing inflammation in your digestive tract (17).
Can Make You Dehydrated
Caffeine is a diuretic, meaning that it increases your rate of urination (3). This can mean that you lose more fluid than usual, which can lead to dehydration that manifests itself by making you feel thirsty.
If you’re not drinking enough water, it can be even more pronounced. It’s particularly important to increase your intake of water if you drink matcha as it may otherwise cause you to become dehydrated rather than properly hydrated.
Can Lead to Anemia
High doses of caffeine and EGCG can both interfere with your body’s ability to absorb iron by binding to the proteins that transport it (2).
As matcha contains both substances, you may not be able to properly absorb the iron that is present in foods if you drink too much green tea. This means that drinking lots of green tea regularly can lead to anemia over time.
If you have difficulty absorbing iron or are at risk of becoming deficient, you should consider talking to your doctor about how much matcha is right for you. Although anemia is rare in most developed parts of the world, certain subpopulations may be more prone to it, such as pregnant women or people with conditions such as celiac disease or inflammatory bowel disease (12).
Contains Tannins That Can Stain Your Teeth
Tannins are plant polyphenols that are found in many different foods, including tea (16). Although tooth enamel is mostly made of calcium and other minerals, tannins can still stick to it if they’re present in high enough concentrations. This is why drinking dark-colored beverages such as black tea or red wine can lead to teeth staining over time (10).
If you drink matcha too often over a long period, the polyphenol content may accumulate on your enamel which can stain them after prolonged exposure. There are ways of preventing this, such as drinking citrus fruit juice (which contains citric acid) after consuming tea. In addition, make sure not to brush your teeth immediately afterward because this may actually make the staining worse.
May Expose You to Toxic Elements
Certain plants contain compounds that are harmful to humans if they’re present in sufficient concentrations. Some of these plants can also become contaminated with elements such as arsenic, lead, cadmium, and mercury over time (9). This is because these elements are naturally found in dirt and water, meaning that they may end up on the leaves of a plant after being exposed to them over some time.
Although it is relatively rare, matcha tea may contain toxic metals such as lead and mercury.
Exposure to high levels of lead can potentially cause damage to your brain, kidneys, lungs, nervous system, and red blood cells (11). The dangers are much lower if you simply drink small amounts regularly, but if you drink it every single day, there’s no way of knowing what sort of effects it could have in the long term.
Mercury is another metal that can accumulate in your body over time, which can be particularly problematic if you constantly drink matcha. Mercury poisoning may cause symptoms such as tremors, memory loss, vision problems, and even seizures (14).
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Drinking It with Milk May Negatively Impact Iron Absorption
Adding milk to your tea for flavor is a common practice as it helps reduce the bitterness of some varieties, including matcha. However, adding milk also decreases your body’s ability to absorb iron from your meals. This is particularly true for heme-iron, which is found in meat products (19).
Non-heme iron that is present in plants is not affected by the addition of milk, but it can still decrease if you drink too much tea or have a condition such as porphyria that causes issues with absorbing this type of iron (15).
Can Cause Acne Breakouts
Matcha contains more caffeine than regular green tea as the whole leaf is consumed when brewing it rather than only the infusion as with conventional steeped green tea. This means that drinking matcha could give you more caffeine than drinking several cups of regular green tea (5).
For some people, this may mean that they end up with more acne as a result. This is because caffeine has been proven to cause acne flare-ups in some people, particularly when it is consumed in large amounts on an empty stomach. If you’re prone to breakouts, it may be best to drink matcha later in the day and avoid drinking too much of it if you know it tends to trigger your pimples.
How Much Matcha Should You Drink to Avoid Unpleasant Side Effects?
There are no studies that say for definite how much matcha is too much. However, it’s likely that matcha green tea side effects vary depending on a person’s age, weight, health status, and amount of exposure to the elements.
Generally, you should try not to consume more than 500 mg of green tea extract or up to 400 mg of caffeine from any source per day unless you are recommended otherwise by your doctor (20). If possible, it’s best to spread out your consumption evenly throughout the day rather than drinking all of it at once as consuming too much can increase your risk of experiencing unpleasant side effects.
Some people may also want to stop or reduce their consumption if they’re pregnant, nursing, taking certain medications (particularly those that contain caffeine), and/or at risk of certain health conditions such as anemia or mercury poisoning that could be exacerbated by the consumption of too much matcha.
The Bottom Line
Matcha tea is a popular beverage that can provide you with a large dose of nutrients, but it’s important to stay within the recommended limits. If you don’t want to give up drinking matcha completely, try limiting your daily consumption to avoid negative side effects such as becoming too caffeinated or irritated in the gut.
Drinking more may be worthwhile if you’re trying to lose weight or increase your focus and energy, but only if you aren’t sensitive to caffeine and don’t have any pre-existing digestive problems.
This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!
- 7 Proven Ways Matcha Tea Improves Your Health (2023, healthline.com)
- Bioactive Dietary Polyphenols Inhibit Heme Iron Absorption in A Dose-Dependent Manner in Human Intestinal Caco-2 cells (2011, ncbi.nlm.nih.gov)
- Caffeine and diuresis during rest and exercise: A meta-analysis (2015, ncbi.nlm.nih.gov)
- Caffeine consumption and self-assessed stress, anxiety, and depression in secondary school children – Gareth Richards, Andrew Smith, 2015 (2015, journals.sagepub.com)
- Caffeine effects on cardiovascular and neuroendocrine responses to acute psychosocial stress and their relationship to level of habitual caffeine consumption (1990, pubmed.ncbi.nlm.nih.gov)
- Common Causes of Chronic Diarrhea (n.d., iffgd.org)
- Effects of caffeine on sleep quality and daytime functioning (2018, ncbi.nlm.nih.gov)
- Green tea for weight loss and weight maintenance in overweight or obese adults ( 2012, pubmed.ncbi.nlm.nih.gov)
- Heavy Metals in Contaminated Soils: A Review of Sources, Chemistry, Risks and Best Available Strategies for Remediation (2011, hindawi.com)
- Iron staining of the acquired enamel pellicle after exposure to tannic acid or chlorhexidine: preliminary report (1982, pubmed.ncbi.nlm.nih.gov)
- Lead toxicity: a review (2015, ncbi.nlm.nih.gov)
- Management of Iron Deficiency Anemia (2011, ncbi.nlm.nih.gov)
- Matcha: Everything You Need to Know (2023, verywellhealth.com)
- Mercury Toxicity and Treatment: A Review of the Literature (2012, hindawi.com)
- Nutrients and Porphyria: An Intriguing Crosstalk (2020, mdpi.com)
- Plant polyphenols as dietary antioxidants in human health and disease (2009, ncbi.nlm.nih.gov)
- Repeated dose studies with pure Epigallocatechin-3-gallate demonstrated dose and route dependant hepatotoxicity with associated dyslipidemia (2016, ncbi.nlm.nih.gov)
- Reasons you shouldn’t drink green tea on an empty stomach (2022, hindustantimes.com)
- Review on iron and its importance for human health (2014, ncbi.nlm.nih.gov)
- The Safety of Ingested Caffeine: A Comprehensive Review (2017, frontiersin.org)