Is There Too Much Aluminum in Tea?

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The tea plant concentrates aluminum from the soil into tea leaves, but phytonutrients in tea bind to the metal and limit its absorption.

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Aluminum is the third most abundant element on Earth, and may not be good for our brain, something we learned studying foundry workers exposed to high levels. Though the role of aluminum in the development of brain diseases like Alzheimer’s is controversial, to be prudent, steps should probably be taken to lessen human exposure to this metal.

There are a number of aluminum-containing drugs on the market like antacids that have the highest levels, though aluminum compounds are also added to processed foods as anti-caking agents in like pancake mix, melting agents in American cheese, meat binders, gravy thickeners, rising agents in some baking powders, and dye-binders in candy. So it’s better to stick to unprocessed, natural foods. However if you cook those natural foods in an aluminum pot, a significant amount can leach into the food, compared to cooking in stainless steel.

If you do the same thing with tea, though, you get a few milligrams of aluminum regardless of what type of pot you use, suggesting the aluminum is in the tea itself. And indeed back in the 1950s, it was noticed that tea plants tend suck up aluminum from the soil, but like anything it’s the dose that makes the poison. According to the World Health Organization, the provisional tolerable weekly intake—our best guess at a safety limit for aluminum, is 2 mg per healthy kilogram of body weight per week, which is nearly a milligram per pound, so someone who’s around 150 pounds probably shouldn’t ingest more than 20 mg of aluminum per day, up to a fifth of intake may come from beverages so what we drink probably shouldn’t contribute more than about 4mg a day, which is the amount found in about 5 cups of green, black, or oolong tea. So should we not drink more than 5 cups of tea a day?

Well, it’s not what we eat or drink, it’s what we absorb. If you just measured how much aluminum was in tea, it would seem as though a couple cups could double aluminum intake for the day, but if you measure the level of aluminum in people’s bodies after they drink tea, it doesn’t go up. This suggests that the bioavailability of aluminum in tea is low, possibly because most of the extractable aluminum in brewed tea is strongly bound to large phytonutrients that are not easily absorbed from the gastrointestinal tract, so it just passes right through you without actually getting into your body. Probably more than 90% of the aluminum in tea is bound up.

But what about studies like this showing a large spike in aluminum excretion through the urine after drinking tea compared to water? The only way for something to get from our mouth to our bladder is to first be absorbed into our bloodstream, but they weren’t comparing the same quantity of tea to water. They had the study subject chug down about 8 and a half cups of tea, or just drink water at their leisure, so they peed a lot more with the tea, so the aluminum content was no different tea versus water, suggesting that gross aluminum absorption from tea is unlikely and that only little aluminum is potentially available for absorption.

So though as few as 4 cups of tea could provide 100% of one’s daily aluminum limit, the percentage available for absorption in the intestine may be less than 10%. Therefore, it is unlikely that moderate amounts of tea drinking can have any harmful effects on humans. However, that’s for people with normal aluminum excretion. For example, tea may not be a good beverage for children with kidney failure, since they can’t get rid of aluminum as efficiently. For most people, though, tea shouldn’t be a problem. Though if you drink tea out of a can, buy undented cans, as the aluminum in dented cans can leach into the liquid boosting aluminum levels by a factor of 8 sitting on store shelves for a year.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.

Please consider volunteering to help out on the site.

Images thanks to AGX via Flickr.

Aluminum is the third most abundant element on Earth, and may not be good for our brain, something we learned studying foundry workers exposed to high levels. Though the role of aluminum in the development of brain diseases like Alzheimer’s is controversial, to be prudent, steps should probably be taken to lessen human exposure to this metal.

There are a number of aluminum-containing drugs on the market like antacids that have the highest levels, though aluminum compounds are also added to processed foods as anti-caking agents in like pancake mix, melting agents in American cheese, meat binders, gravy thickeners, rising agents in some baking powders, and dye-binders in candy. So it’s better to stick to unprocessed, natural foods. However if you cook those natural foods in an aluminum pot, a significant amount can leach into the food, compared to cooking in stainless steel.

If you do the same thing with tea, though, you get a few milligrams of aluminum regardless of what type of pot you use, suggesting the aluminum is in the tea itself. And indeed back in the 1950s, it was noticed that tea plants tend suck up aluminum from the soil, but like anything it’s the dose that makes the poison. According to the World Health Organization, the provisional tolerable weekly intake—our best guess at a safety limit for aluminum, is 2 mg per healthy kilogram of body weight per week, which is nearly a milligram per pound, so someone who’s around 150 pounds probably shouldn’t ingest more than 20 mg of aluminum per day, up to a fifth of intake may come from beverages so what we drink probably shouldn’t contribute more than about 4mg a day, which is the amount found in about 5 cups of green, black, or oolong tea. So should we not drink more than 5 cups of tea a day?

Well, it’s not what we eat or drink, it’s what we absorb. If you just measured how much aluminum was in tea, it would seem as though a couple cups could double aluminum intake for the day, but if you measure the level of aluminum in people’s bodies after they drink tea, it doesn’t go up. This suggests that the bioavailability of aluminum in tea is low, possibly because most of the extractable aluminum in brewed tea is strongly bound to large phytonutrients that are not easily absorbed from the gastrointestinal tract, so it just passes right through you without actually getting into your body. Probably more than 90% of the aluminum in tea is bound up.

But what about studies like this showing a large spike in aluminum excretion through the urine after drinking tea compared to water? The only way for something to get from our mouth to our bladder is to first be absorbed into our bloodstream, but they weren’t comparing the same quantity of tea to water. They had the study subject chug down about 8 and a half cups of tea, or just drink water at their leisure, so they peed a lot more with the tea, so the aluminum content was no different tea versus water, suggesting that gross aluminum absorption from tea is unlikely and that only little aluminum is potentially available for absorption.

So though as few as 4 cups of tea could provide 100% of one’s daily aluminum limit, the percentage available for absorption in the intestine may be less than 10%. Therefore, it is unlikely that moderate amounts of tea drinking can have any harmful effects on humans. However, that’s for people with normal aluminum excretion. For example, tea may not be a good beverage for children with kidney failure, since they can’t get rid of aluminum as efficiently. For most people, though, tea shouldn’t be a problem. Though if you drink tea out of a can, buy undented cans, as the aluminum in dented cans can leach into the liquid boosting aluminum levels by a factor of 8 sitting on store shelves for a year.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.

Please consider volunteering to help out on the site.

Images thanks to AGX via Flickr.

Nota del Doctor

What about the levels and absorbability of the aluminum in my other favorite type of tea? Find out in my next video, How Much Hibiscus Tea is Too Much?

The tea plant also sucks up fluoride. So much so that heavy tea drinking can stain the teeth of children. See my video Childhood Tea Drinking May Increase Fluorosis Risk.

Why should we go out of our way to drink tea? See:

Is Caffeinated Tea Dehydrating? Find out by watching the video!

For more on metals in our food supply, see:

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