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Metal content in loose tea vs tea bags

Posted by CTH Blog 04/09/2021 01:24:38 Healthy Tea 0 Comments

Everyone may be talking about EGCG, caffeine and L-theanine, but there’s so much more to tea than caffeine, catechins and amino acids. Tea contains other compounds too, including vitamins and minerals – or trace metals. Yes, all those micronutrients that our body needs are present in tea too. What are metals in tea exactly and who has more – loose tea or tea bags?

What metals may be present in tea?

Tea contains different compounds. Studies showed that all of them may provide some benefits, such as antioxidant, anti-inflammatory or antibacterial activity. The list of compounds in tea is long, but on that long list, metals are often neglected. Metals present in tea are nickel, copper, iron, zinc, aluminum[1], manganese, potassium, phosphorus, magnesium and others. Some of them may be beneficial, some may show neither positive nor negative impact on health, and some may be dangerous. And some may be present in larger amounts than the others, which may be both good and bad.

The good metals

Our bodies need micronutrient to function properly and stay healthy. Except vitamins, minerals are important too. They are also called trace elements or trace metals. For example, calcium, iron and magnesium are the most commonly added minerals to different drinks and food. They are naturally present in tea too. One study showed that high quality Chinese green tea contains much more zinc, manganese, magnesium, potassium, calcium and aluminum than black tea and may enhance the mineral balance of our bodies[2]. Don’t expect outrageous amounts, though. Studies suggest that 4 cups of tea per day may provide only 5% of the daily magnesium needs and 4-5% of potassium needs[3]. A mineral that you may get in large quantities from daily tea drinking is manganese, which is likely to be abundant in black tea[4].

The heavy metals

Tea is a healthy drink, indeed, but sometimes good things may come at the high price. And by high price, we don’t mean the price tag, but the potential negative effects that a cup of tea may have on your health. One of them my come from a high heavy metal content in tea. Unlike minerals, heavy metals should be avoided. Just like nutrients, they may get into the plant from the environment – soil, water and air.

Over the years, heavy metals received a terrible reputation. And there’s a good reason for that. Heavy metals are metals that may be very toxic or even cancerogenic. However, here’s where things gets even more complicated. The list of heavy metals is long, and it includes silver, arsenic, cadmium, copper, chromium, mercury, nickel, lead and zinc[5]. However, some of them, such as copper, chromium and zinc, are actually beneficial for our health – usually in lower doses. But others, such as mercury, may cause serious health issues, such as brain damage[6].

How is tea grown?

Tea can be grown in different ways. Some teas are grown on cultivated tea plantations, other may grow freely in the nature. Some may come from smaller tea bushes, the others may be harvested from, sometimes centuries old, tea trees. Tea can be grown from different tea varieties and cultivars, each of them having slightly different chemical composition. To grow healthy, tea plants need a good soil, good weather and non-harmful fertilizers and pesticides. That’s where organic farming wins. For a tea to be organic, it needs to be grown under special conditions – on soil that wasn’t treated with any prohibited substances years before the first harvest[7].

Tea is available in loose leaf form and tea bags. Loose leaf can be whole and broken, while traditional tea bags usually contain tea dust and fannings.

metal content loose tea vs tea bags Image by Mirko Stödter

What are studies saying?

A recent Polish study compared different types of tea, white, green, black, dark and oolong, both in tea bags and as loose leaf tea, to determine the levels of both good and bad metals. Results suggested that black tea may have the highest levels of manganese and copper. All types of tea in the study, white, green, black and oolong had similar levels of zinc. The study included “bad” metals too. On of them, cadmium, may cause severe side effects[8]. Interestingly, out of all tea samples, the highest amounts were found in a green tea bag[9].

Another study compared mineral content of different types of Indian teas, both whole leaf teas and dust. It showed that whole leaf teas had more calcium, cooper, manganese, magnesium and iron than tea dust. Furthermore, Assam whole leaf showed the highest levels of minerals in total, while Nilgiri tea was especially rich in manganese[10].

All these minerals, including heavy metals, will need to be extracted into your cup. The leaf particle size, water temperature, stepping time and the amount of leaves you use will all have an influence on how much of both good and bad compounds will be extracted. One study explored how many heavy metals will be extracted into your cup at different steeping times. It showed that 3 minutes steep will extract less lead than 15 minutes steep. But most surprisingly, mercury, even if present in tea leaves, won’t be extracted in boiling water at all[11]. Therefore, steeping won’t increase your change of mercury intake from tea[12].

Should you be drinking tea?

Based on studies, tea may indeed be a very healthy drink. Just like with any other food or drink, even water, not all teas are made the same. Water, too, may contain both good and bad metals. And finally, always brew your tea with a freshly boiled spring water, rather than tap water, especially if it’s not suitable for drinking.

Buying organic when possible and making sure your tea comes from a reliable source is of the utmost importance if you want to enjoy it carefree. Loose leaf tea is often of a higher quality than tea bags, not only because of its flavor, scent and appearance, but nutritional value too.

Disclaimer: This article does not replace a professional medical advice.