One of the most common misconceptions about the term “organic” is the idea that organic is always good for you. We’ve found from testing poorly regulated supplements and food products that labels and packaging, no matter how well-designed, can be deceptively comforting. It’s why we’ve tested over 800 supplements at labdoor.com, including herbal supplements like green tea, ginseng, and vegan omega-3 for heavy metal contamination. For more on our quality testing results, head over to our rankings here: https://labdoor.com/rankings.
In this article, we’ll explain how heavy metals get into plant-based products using tea as an example, and we’ll look at research-backed data to compare how standard versus organic teas fare.
Chronic Heavy Metal Poisoning
In the most mundane ways, we’re exposed to small amounts of heavy metals everyday through food, water, air, and commercial products. Certain plastic toys, herbal medicines, and even tap water sources have all been found at some point to be tainted with heavy metals.
We know from a substantial body of research that absorbing heavy metals can be damaging. Health effects of chronic, low-level exposure run the gamut from feeling tired to immune system impairment to mental disorders to cancer. Heavy metals can also accumulate in our bodies over time, causing symptoms to appear slowly and leading to illness much later on in life, even possibly affecting our genes via “epigenetic changes” so that damage is transferrable to following generations.
The proven relationship between certain metal exposures and illness is why governing bodies have established limits for safe daily exposure levels:
Tea Plants Are Adapted to Soak Up Heavy Metals
Plants get their heavy metals from contaminated soil, and contaminated soil is a product of industrialization. Mining, automobile activity, gas-powered manufacturing, and the use of synthetic chemicals (e.g. pesticides, paints, batteries, industrial waste) all contribute to urban and agricultural soil contamination. Lead and aluminum, specifically, tend to sit out in the earth’s top most soil layers.
All plants that grow in contaminated environments will pick up some of the soil’s contaminants, and the tea plant, Camellia sinensis, is no exception. Because tea grows on acidic soil and aluminum and lead are made more soluble as acidity rises, C. sinensis has adapted a mechanism to thrive in spite of the high heavy metal levels. Research has found that C. sinensis is a special type of plant called a “hyperaccumulator”, a plant that has built-in molecular mechanisms to extract metals from the soil and then collect those metals in its leaves without harming its growth.
Tea plants soak up metals on their own, but the manufacturing process plays a significant role too. For example, teas with a higher percentage of old leaves can have higher metal loads because those older leaves by nature will have had more time to gather heavy metals. One study found that aluminum concentrations in old leaves can be 20 times higher than in young leaves. Another study also showed that the mere twisting and water-removal stages in normal tea production caused an increase in lead content of the tea product being studied.
The data below come from a study looking at lead and aluminum levels in teas from different processing methods (e.g. green vs. white vs. black vs. oolong) and different organic standards. It assumes an average tea consumption of 3 cups (or 500 mL) per day.
To be fair, this data has some limitations. Most importantly, we’re looking at one study and a very limited sample of teas, so the conclusions we draw may not be universal. Still, some glaring observations are apparent:
1) Teas can have dangerously high levels of metals.
In the study, 83% of the teas exceed safe lead limits during pregnancy. Black teas performed best in lead safety while oolong teas were worst. Green and white teas were somewhere in between. Aluminum levels can also be concerning in tea products. Research predicts that for many people, tea can be the most important single source of dietary aluminum. A daily diet of 3 cups of tea coupled with other daily sources of heavy metals like water, other beverages, and produce can easily exceed safe heavy metal limits for the average adult.
2) Steeping teas for longer than 3 minutes should be avoided.
The researchers estimate that metal load increased by 10–50% at 15–17 minutes compared to at 3 minutes alone.
3) Organic tea might be better, but only some of the time.
More or less, the tested organic teas had lower heavy metal levels than non-organic teas. Organic oolong teas, for example, had on average, 40% lower lead concentrations than standard oolong teas brewed for 3–4 minutes.
Interestingly though, green teas showed the opposite trend. Organic green teas in the study had more than 30% higher lead concentrations than regular green teas. With a 3–4 minute steeping time, the highest level of lead found in an organic green tea product was 1.54 ug/600mL. The highest lead level in a standard green tea product was only 1.13 ug/600mL.
Unfortunately, that’s where the story ends in the research. We have a surprising finding, but no documented mechanism yet to explain it. Various theories could account for it though, like organic plants developing more powerful plant mechanisms to sequester contaminants or simply a lack of oversight in organic tea quality control. For now, we can limit some of the risk factors for heavy metal poisoning by using distilled water instead of tap water for brewing, choosing safe containers for steeping, and monitoring steeping time.
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