Toxic Tea? Since the dawn of time tea has been a significant part of the human diet. According to the Tea Association, in 2014 Americans consumed 3.6 billion gallons of tea. All true teas are derived from the leaves of the Camellia sinensis tea plant, so they share similar biochemistry.
Some of tea’s phytochemicals are very health promoting, however we do find evidence of toxins in tea, particularly pesticides and heavy metals. Tea plants are “hyperaccumulators,” meaning they are extremely proficient at extracting agents from the soil and accumulating them in their leaves—and therein lies the concern. Factors such as where a tea is grown and how it’s processed and packaged must be considered, right down to the tea bag. Despite toxicity concerns, tea can still be a beneficial part of a healthy diet—you just have to know what to look for. In this article, you will learn how to tailor your tea consumption for maximal health benefits and minimal risk.
Thousands of tea cultivars are derived from the primary Camellia sinensis varieties, and they can all be categorized into five basic types of tea based on how they’re processed. The specific health benefits and potential concerns differ for each variety of tea, so it’s useful to have a basic understanding of the types, which are differentiated by withering method (leaf drying), oxidation and fermentation. The five basic types of tea are differentiated as follows:
- White Tea: Made from unopened buds and immature leaves that are steamed or fired to inactivate polyphenol oxidase, and then dried.
- Green Tea: Made from more mature leaves than white tea, the leaves are typically withered prior to steaming or firing, and then rolled and dried.
- Oolong (Wu long) Tea: Leaves are “bruised” in order to release some of their polyphenol oxidase which acts to partially oxidize the tea, then are heated and dried.
- Black Tea: Fully rolled or broken to maximize oxidation before drying.
- Pu-erh Tea (Pu’er Tea or Chinese Black Tea): A black tea from the Yunnan province of China that has undergone a complex process of fermentation and aging.
A Tour Through Tea’s Health-Promoting Benefits
Tea contains more than 2,000 components—a medley of polyphenols or flavonoids, catechins, pigments, alkaloids, amino acids, vitamins, minerals and trace elements—and many are bioactive. Two of the most valuable compounds in tea include epigallocatechin gallate (EGCG) and theanine, also known as L-theanine. EGCG has far-reaching health benefits including antioxidant, anti-inflammatory, anti-proliferative, anti-infective, and cardioprotective. Tea is the only plant that makes the amino acid theanine, known for calming and focusing the mind and reducing stress. (1)
Traditional Chinese Medicine and Ayurveda have used teas for centuries to improve digestion, accelerate wound healing, stabilize blood sugar, improve heart health and boost mental function. Science supports the following health benefits from tea: (2)
- Cardiovascular disease, lipids profile and hypertension (3, 4, 5)
- Type 2 diabetes, obesity, glucose metabolism and insulin (6, 7, 8)
- Cancers of the lung, gastrointestinal tract, breast, prostate, skin, brain, and blood (9, 10)
- Bone and dental health (11, 12)
- Kidney stones (13)
- Mood and cognition (14, 15, 16)
- Parkinson’s disease (17)
What About the Caffeine?
Caffeine is a universal component of the Camellia sinensis tea plant so it is present in all teas—be they green, red or white. The amount transferred into your cup varies by the specific tea variety, quantity used and how long the leaves are steeped. The more leaves you use and the longer you brew them, the higher the caffeine level.
Although many herbal teas are caffeine-free, you might be surprised to learn that not ALL of them are. When it comes to tea blends—for example chai—read your labels because they often include a combination of herbs and tea leaves.
Some herbal tea blends contain cocoa leaves or extracts that are naturally caffeinated. Yerba mate, guayusa and yaupon are plants used for “herbal tea” that contain substantial amounts of caffeine. Caffeine can also be present as a contaminant. The Journal of Food Science (18) found that when tested, many common herbal teas contain trace amounts of caffeine. This may be due to the fact that many are produced in the same factories as regular teas, resulting in cross contamination. These trace amounts will likely go unnoticed unless you are highly caffeine sensitive.
Getting back to the caffeine content in regular teas, green tea contains roughly one-quarter of the caffeine of coffee and one-half that of black tea. One eight-ounce cup of green tea steeped for three minutes contains about 25 milligrams of caffeine, as a general rule. For a comparison of caffeine and nutrient levels for various Japanese green teas, refer to this page.
Although tea is lower in caffeine than coffee, this may still be too much for some individuals. In general, the caffeine in tea seems to produce fewer problematic effects (jitters, anxiety, headaches, insomnia, diarrhea, irregular heartbeat, etc.), which may be related to its natural theanine content. When combined with caffeine, theanine tends to produce more of a “quiet alertness” as opposed to the more jolting and jittery high of coffee. (19)
Tea Plants Drink Up Pesticides and Heavy Metals Like a Sponge
China is the world’s largest tea producer with eight million tea growers, as well as the world’s largest pesticide user. Most tea is not washed before it’s packaged or bagged, so if the plants are doused in pesticides they will be infusing into your cup. Besides pesticides, teas may contain artificial coloring, flavoring and GMOs. In 2012, a comprehensive investigation by Greenpeace found all tea samples from China tested positive for at least three kinds of pesticides, with one-third containing up to 29 different pesticides—many of which are illegal. (20)
Tea plants naturally accumulate fluoride and other heavy metals (lead, aluminum, arsenic) and typically grow in acidic soils, which results in even higher uptake. (21) Fluoride toxicity can result in a variety of health problems such as joint pain, muscle weakness, osteoporosis, brittle teeth, kidney problems and even cancer. (22) There is growing evidence aluminum is problematic for your brain and may contribute to Alzheimer’s disease. (23)
Lower quality teas have more heavy metals because they consist of fallen, older leaves, while newer top leaves and buds that have absorbed less are reserved for higher grade tea products. One study found aluminum concentrations in old tea leaves 20 times higher than in young leaves. (24) Decaffeinated tea has more fluoride than caffeinated tea, and black tea has more fluoride than green or white tea. (25, 26) Instant tea also tests high in fluoride. (27)
Organic tea can be expected to have less pesticide contamination, but what about heavy metals and other toxic elements?
Organic tea might be cleaner but only some of the time. Given that younger tea leaves tend to be less contaminated than older ones, you would expect higher grade teas to be less toxic—but this is only a rule of thumb. Another consideration is that teas from China and India are generally more contaminated than those from Japan due to industrialization. So if you enjoy green tea, your best option is organically grown green tea from Japan.
Tea bags have their own set of problems. Most paper tea bags are treated with epichlorohydrin, a known carcinogen. Silky tea bags are made from plastics such as nylon or polypropylene, which are unstable in hot water. Consider bagging the bags altogether and opting instead for loose leaf.
Twelve Tips for the Tea Drinker
Is your head spinning yet? I’m not surprised—tea is a complex and multi-faceted topic. As you’ve probably already concluded, there is no precise “formula” for choosing the best tea. However, equipped with a basic understanding of the multiple factors contributing to its benefits and risks, you can make better choices. Doing what you can to reduce your “cumulative burden” of toxins is paramount.
I have put together a list of basic principles for you to keep in mind as you shop for tea, which will help you maximize your health benefits while minimizing your risk. If you want to see how some of your favorite teas rate, Food Babe and Clean Plates have comparisons you might find helpful.
- First and foremost, choose certified organic and non-GMO brands of tea.
- Read labels carefully. Avoid tea products with added flavors (even “natural” flavors), potential GMO ingredients such as soy lecithin and corn starch, corn syrup and other additives.
- Avoid tea supplements, concentrates, instant tea and other processed tea products.
- Avoid teas from China and India, opting instead for teas from Japan, ideally organic; cross Chinese black teas off your list entirely due to universally high contamination levels.
- Use loose leaf tea instead of bagged tea whenever possible. Choose stainless steel or glass tea strainers. Numi and Traditional Medicinals have publicly stated their bags are epichlorohydrin free, so those may be acceptable options.
- Use filtered water instead of tap water. Be aware that some fine china (especially older china) is made with heavy metals that can leach into your tea.
- Steeping for more than three minutes increases heavy metal infusion, particularly lead and aluminum.
- Restaurants ordinarily use some of the cheapest and most contaminated brands of tea, so consider bringing your own teabag and just ordering hot water.
- It’s optimal to drink your green tea at least two hours before or after meals in order to harness its full benefits. Catechins react with casein (present in milk and animal proteins), reducing antioxidant benefits. Green tea may inhibit digestion and absorption of calcium and thiamin. Be aware that tea can interact with a number of medications. (28)
- If you have a gastrointestinal disorder or liver problems, be extra careful about the teas you consume. Although studies show green tea can significantly protect your liver, (29) there are also cases of hepatotoxicity from tea, and the cause is poorly understood (30). Consuming large quantities of contaminated tea with a compromised liver is a recipe for disaster.
- Make sure to make detox protocols a regular part of your health regimen.
- If you don’t like tea or are very sensitive to caffeine, caffeine-free herbal teas offer great health benefits, such as rooibos from South Africa (avoid those from India) and tulsi tea (holy basil).